ORCID Profile
0000-0002-3853-0096
Current Organisation
University of South Australia
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Environmental Science and Management | Environmental Engineering Design | Water And Sanitary Engineering | Environmental Engineering Modelling | Environmental Engineering | Environmental Technologies | Veterinary Sciences | Civil Engineering | Plant Biology | Natural Resource Management | Parasitology | Medical Parasitology | Urban And Regional Planning | Plant Physiology | Ecosystem Function | Environmental Impact Assessment | Forestry Management and Environment | Environmental Management | Environmental Chemistry (Incl. Atmospheric Chemistry) | Microbial Ecology | Sociobiology And Behavioural Ecology |
ANZSRC Socio-Economic Objective (SEO)
Environmental Lifecycle Assessment | Ecosystem Assessment and Management of Forest and Woodlands Environments | Infectious diseases | Integrated (ecosystem) assessment and management | Biological sciences | Climate change | Physical and chemical conditions | Land and water management | Physical and chemical conditions | Environmental education and awareness | Prevention—biologicals (e.g. vaccines) | Electricity, gas and water services and utilities | Environmental Health | Sustainability Indicators
Related Links
Publications
Establishment and early succession of bacterial communities in monochloramine-treated drinking water biofilms
Publisher: Oxford University Press (OUP)
Date: 17-07-2013
Abstract: Monochloramine is an increasingly used drinking water disinfectant and has been shown to increase nitrifying bacteria and mycobacteria in drinking waters. The potential successions and development of these bacteria were examined by 16S rRNA gene clone libraries generated from various biofilms within a water distribution system simulator. Biofilms were obtained from in-line and off-line devices using borosilicate glass beads, along with polycarbonate coupons from annular reactors incubated for up to 8 months in monochloramine-treated drinking water. No significant difference in community structures was observed between biofilm devices and coupon material however, all biofilm communities that developed on different devices underwent similar successions over time. Early stages of biofilm formation were dominated by Serratia (29%), Cloacibacterium (23%), Diaphorobacter (16%), and Pseudomonas (7%), while Mycobacterium-like phylotypes were the most predominant populations (> 27%) in subsequent months. The development of members of the nontuberculous mycobacteria (NTM) after 3 months may impact in iduals with predisposing conditions, while nitrifiers (related to Nitrospira moscoviensis and Nitrosospira multiformis) could impact water quality. Overall, 90% of the ersity in all the clone library s les was associated with the phyla Proteobacteria, Actinobacteria, and Bacteroidetes. These results provide an ecological insight into biofilm bacterial successions in monochloramine-treated drinking water.
Risk-based treatment targets for onsite non-potable water systems using new pathogen data
Publisher: IWA Publishing
Date: 09-09-2022
DOI: 10.2166/WH.2022.135
Abstract: Using local sources (roof runoff, stormwater, graywater, and onsite wastewater) to meet non-potable water demands can minimize potable water use in buildings and increase supply reliability. In 2017, an Independent Advisory Panel developed a risk-based framework to identify pathogen log reduction targets (LRTs) for onsite non-potable water systems (ONWSs). Subsequently, California's legislature mandated the development and adoption of regulations—including risk-based LRTs—for use in multifamily residential, commercial, and mixed-use buildings. A California Expert Panel was convened in 2021 to (1) update the LRT requirements using new, quantitative pathogen data and (2) propose treatment trains capable of meeting the updated LRTs. This paper presents the updated risk-based LRTs for multiple pathogens (viruses, protozoa, and bacteria) and an expanded set of end-uses including toilet flushing, clothes washing, irrigation, dust and fire suppression, car washing, and decorative fountains. The updated 95th percentile LRTs required for each source water, pathogen, and end-use were typically within 1-log10 of the 2017 LRTs regardless of the approach used to estimate pathogen concentrations. LRT requirements decreased with influent pathogen concentrations from wastewater to graywater to stormwater to roof runoff. Cost and footprint estimates provide details on the capital, operations and maintenance, and siting requirements for ONWS implementation.
Microbial Contamination of Drinking Water and Human Health from Community Water Systems
Publisher: Springer Science and Business Media LLC
Date: 27-01-2015
Disruption of Two Defensive Signaling Pathways by a Viral RNA Silencing Suppressor
Publisher: Scientific Societies
Date: 07-2010
Abstract: The Cucumber mosaic virus (CMV) 2b counter-defense protein disrupts plant antiviral mechanisms mediated by RNA silencing and salicylic acid (SA). We used microarrays to investigate defensive gene expression in 2b-transgenic Arabidopsis thaliana plants. Surprisingly, 2b inhibited expression of few SA-regulated genes and, in some instances, enhanced the effect of SA on certain genes. Strikingly, the 2b protein inhibited changes in the expression of 90% of genes regulated by jasmonic acid (JA). Consistent with this, infection of plants with CMV, but not the 2b gene-deletion mutant CMVΔ2b, strongly inhibited JA-inducible gene expression. JA levels were unaffected by infection with either CMV or CMVΔ2b. Although the CMV–Arabidopsis interaction is a compatible one, SA accumulation, usually considered to be an indicator of plant resistance, was increased in CMV-infected plants but not in CMVΔ2b-infected plants. Thus, the 2b protein inhibits JA signaling at a step downstream of JA biosynthesis but it primes induction of SA biosynthesis by another CMV gene product or by the process of infection itself. Like many plant viruses, CMV is aphid transmitted. JA is important in plant defense against insects. This raises the possibility that disruption of JA-mediated gene expression by the 2b protein may influence CMV transmission by aphids.
Comparing the Life Cycle Energy Consumption, Global Warming and Eutrophication Potentials of Several Water and Waste Service Options
Publisher: MDPI AG
Date: 20-04-2016
DOI: 10.3390/W8040154
Improving the implementation of water and resource recovery in Canada
Publisher: IWA Publishing
Date: 03-03-2021
DOI: 10.2166/WRD.2021.087
Abstract: Globally there is a need to rethink water use and wastewater disposal. One view is to consider wastewater as a resource via treatment for fit-for-purpose water and resource recovery (WRR). To understand what has worked in Canada according to those directly involved in WRR, we used interviews with in iduals involved in various WRR projects. Seventeen semi-structured interviews were completed with participants from regions across Canada. Three main findings pertaining to the question ‘what is needed for WRR project implementation?’ emerged from the interviews: government and institutional support community engagement, education, and acceptance and comprehensive planning. Based on the interview findings, WRR projects require foundational guidance, something that is currently lacking in the Canadian context. To improve WRR implementation and success in Canada, guidance on community engagement, technology, costs, and impact assessments should be built into a policy for WRR.
Microbial diversities (16S and 18S rRNA gene pyrosequencing) and environmental pathogens within drinking water biofilms grown on the common premise plumbing materials unplasticized polyvinylchloride and copper
Publisher: Oxford University Press (OUP)
Date: 24-02-2014
Abstract: Drinking water (DW) biofilm communities influence the survival of opportunistic pathogens, yet knowledge about the microbial composition of DW biofilms developed on common in-premise plumbing material is limited. Utilizing 16S and 18S rRNA gene pyrosequencing, this study characterized the microbial community structure within DW biofilms established on unplasticized polyvinyl chloride (uPVC) and copper (Cu) surfaces and the impact of introducing Legionella pneumophila (Lp) and Acanthamoeba polyphaga. Mature (> 1 year old) biofilms were developed before inoculation with sterilized DW (control, Con), Lp, or Lp and A. polyphaga (LpAp). Comparison of uPVC and Cu biofilms indicated significant differences between bacterial (P = 0.001) and eukaryotic (P 0.05) but did affect eukaryotic members (uPVC, P < 0.01 Cu, P = 0.001). Thus, established DW biofilms host complex communities that may vary based on substratum matrix and maintain consistent bacterial communities despite introduction of Lp, an environmental pathogen.
SURVIVAL OF FECAL MICROORGANISMS IN MARINE AND FRESH-WATER SEDIMENTS
Publisher: American Society for Microbiology
Date: 05-1995
DOI: 10.1128/AEM.61.5.1888-1896.1995
Abstract: The survival of culturable fecal coliforms, fecal streptococci, and Clostridium perfringens spores in freshwater and marine sediments from sites near sewage outfalls was studied. In laboratory studies, the inhibition of protozoan predators with cycloheximide allowed the fecal coliforms to grow in the sediment whereas the presence of predators resulted in a net die-off. C. perfringens spores did not appear either to be affected by predators or to die off throughout the duration of the experiments (28 days). Studies using in situ membrane diffusion chambers showed that, with the exception of C. perfringens, die-off of the test organisms to 10% of their initial numbers occurred in both marine and freshwater sediments within 85 days. The usual exponential decay model could not be applied to the sediment survival data, with the exception of the data for fecal streptococci. It was concluded that application of the usual decay model to the fecal coliform data was confounded by the complex relationship between growth and predation. The survival of seeded Escherichia coli in marine sediment was studied by using an enumeration method which detected viable but nonculturable bacteria. Throughout the duration of the experiment (68 days), the same proportion of E. coli organisms remained culturable, suggesting that sediment provides a favorable, nonstarvation environment for the bacteria.
Evaluation of Kluyveromyces marxianus FII 510700 grown on a lactose-based medium as a source of a natural bioemulsifier
Publisher: Oxford University Press (OUP)
Date: 12-2003
DOI: 10.1007/S10295-003-0105-6
Abstract: Mannoprotein with emulsification properties was extracted from the cell walls of Kluyveromyces marxianus grown on a lactose-based medium by autoclaving cells in a citrate buffer at pH 7. The purified product was evaluated for chemical and physical stability to establish its potential use as a natural emulsifier in processed foods. The yield of purified bioemulsifier from this strain of K. marxianus was 4-7% of the original dry cell weight. The purified product, at a concentration of 12 g l(-1), formed emulsions that were stable for 3 months when subjected to a range of pH (3-11) and NaCl concentrations (2-50 g l(-1)). The composition of this mannoprotein was 90% carbohydrate (mannan) and 4-6% protein. These values are similar to mannoprotein extracted from cells of Saccharomyces cerevisiae, which is the traditional source. Consequently K. marxianus cultivated on a low-cost lactose-based medium such as whey, a lactose-rich clean waste of the dairy industry, could be developed as a source of bioemulsifier for use in the food industry.
Comparing probabilistic microbial risk assessments for drinking water against daily rather than annualised infection probability targets
Publisher: IWA Publishing
Date: 07-2009
DOI: 10.2166/WH.2009.101
Abstract: Some national drinking water guidelines provide guidance on how to define ‘safe’ drinking water. Regarding microbial water quality, a common position is that the chance of an in idual becoming infected by some reference waterborne pathogen (e.g. Cryptsporidium) present in the drinking water should & −4 in any year. However the instantaneous levels of risk to a water consumer vary over the course of a year, and waterborne disease outbreaks have been associated with shorter-duration periods of heightened risk. Performing probabilistic microbial risk assessments is becoming commonplace to capture the impacts of temporal variability on overall infection risk levels. A case is presented here for adoption of a shorter-duration reference period (i.e. daily) infection probability target over which to assess, report and benchmark such risks. A daily infection probability benchmark may provide added incentive and guidance for exercising control over short-term adverse risk fluctuation events and their causes. Management planning could involve outlining measures so that the daily target is met under a variety of pre-identified event scenarios. Other benefits of a daily target could include providing a platform for managers to design and assess management initiatives, as well as simplifying the technical components of the risk assessment process.
Characterization of water treatment-resistant and multidrug-resistant urinary pathogenic Escherichia coli in treated wastewater
Publisher: Elsevier BV
Date: 09-2020
Fluorescence resonance energy transfer (FRET)-based specific labeling of Cryptosporidium oocysts for detection in environmental samples
Publisher: Wiley
Date: 23-04-2004
DOI: 10.1002/CYTO.A.20020
Abstract: Accurate detection and quantification of Cryptosporidium oocysts in water are a challenge to the water industry. This article demonstrates a way to fluorescently label Cryptosporidium oocysts, based on fluorescence resonance energy transfer (FRET). Labeled oocysts can then be applied to environmental waters and their movement followed by flow cytometric detection and enumeration of the FRET-labeled oocysts, as demonstrated here with environmental water s les. Cryptosporidium oocysts were labeled with three fluorochromes, FITC, Texas red, and Cy7, that through FRET yielded a Stokes shift of approximately 272 nm with excitation from a standard argon laser emitting at 488 nm. Defined flow cytometric settings and gatings were used to select FITC/green (530-nm), Texas red/red (650-nm), and Cy7/infrared (780-nm) fluorescing particles with light scatter properties similar to oocysts. Water concentrates were seeded with 10 tri-labeled oocysts and were analyzed using flow cytometry. Unseeded water concentrates were also analyzed. Analysis of unseeded water concentrates detected no autofluorescent particle similar to the labeled oocysts. Labeled oocysts were detected successfully with up to 85% recovery in water concentrates spiked with 10 tri-labeled oocysts. Low numbers of FRET-labeled oocysts can be quantified and clearly distinguished from autofluorescing background in environmental water concentrates.
A theoretical approach to assess microbial risks due to failures in drinking water systems
Publisher: Informa UK Limited
Date: 06-2003
Reply to comments on “Derivation of numerical values for the World Health Organization guidelines for recreational waters”
Publisher: Elsevier BV
Date: 05-2006
DOI: 10.1016/J.WATRES.2006.02.009
Abstract: The contribution addressed reveals an optimistic design philosophy likely to systematically underestimate risk in epidemiologic studies into the health effects of bathing water exposures. The authors seem to recommend that data on the 'exposure' measure (i.e. water quality) in such studies should be acquired in a similar manner to that used for regulatory s ling. This approach may compromise the quality of the epidemiologic investigations undertaken. It may result in imprecise estimates of exposure because it ignores the fact that regulatory timescales and spatial resolution (even if artificially compressed to a bathing day) can mask large spatial and temporal variability in water quality. If this variability is ignored by taking some mean value and attributing that to all of those exposed in a period at a study location, many bathers may be misclassified and the studies may be biased to a 'no-effect' conclusion. A more appropriate approach is to maximise the precision of the epidemiologic investigations by measurement of in idual exposure (or water quality) at the place and time of the exposure, as has been done in randomised volunteer studies in the UK and Germany. The precise epidemiologic relationships linking 'exposure' with 'illness' can then be related to the probability of exposure to particular water quality by a 'normal bather' using the known probability distribution of the exposure variable (i.e. faecal indicator concentration) in the regulated bathing waters. We suggest that any research protocol where poor s ling design for water quality assessment is justified because regulatory monitoring is equally imprecise may be fundamentally flawed. The rationale for this assessment is that the epidemiology is the starting point and evidence-base for 'standards'. If precision is not maximised at this stage in the process it compromises the credibility of the standards design process. The negative effects of the approach advocated in this 'comment' are illustrated using published research findings used to derive the figures illustrated in Wymer et al. [2005. Comment on derivation of numerical values for the World Health Organization guidelines for recreational waters. Water Research 39, 2774-2777].
An improved culture method for selective isolation of Campylobacter jejuni from wastewater
Publisher: Frontiers Media SA
Date: 26-08-2016
Persistence of two model enteric viruses (B40-8 and MS-2 bacteriophages) in water distribution pipe biofilms
Publisher: IWA Publishing
Date: 06-2001
Abstract: The persistence of two model enteric virions (Bacteroides fragilis phage B40-8 and coliphage MS-2) within pipe biofilms was investigated in situ in an urban distribution system. Biofilms were allowed to develop on uPVC and stainless steel (SS) coupons in a modified Robbins' device for 70 d within a 150 mm uPVC reticulation main. Coupons were then placed in annular reactors and slug dosed with B40-8 and MS-2 phages (108 pfu/mL). Pipe water velocity, pH and free chlorine were recorded during the experimental period. Biofilms on uPVC were generally more abundant (based on total bacterial counts, HPCs, total protein and total carbohydrate). Both B40-8 and MS-2 were incorporated into biofilms formed on uPVC and SS coupons (& and & pfu/μg protein respectively) and persisted for & d and 6 d respectively, reflecting biofilm biomass on the two pipe surfaces. Virion loss/inactivation from biofilm followed an initial rapid phase, followed by a very slow phase representing approximately 0.01% of the original virion population. Virions, therefore, have the potential to accumulate within distribution biofilm and problems could arise when clusters of biofilm-associated enteric virions become detached from the substrata by hydrodynamic forces or sudden changes in disinfection regime.
Evaluating the importance of faecal sources in human-impacted waters
Publisher: Elsevier BV
Date: 04-2011
DOI: 10.1016/J.WATRES.2011.02.025
Abstract: Quantitative microbial risk assessment (QMRA) was used to evaluate the relative contribution of faecal indicators and pathogens when a mixture of human sources impacts a recreational waterbody. The waterbody was assumed to be impacted with a mixture of secondary-treated disinfected municipal wastewater and untreated (or poorly treated) sewage, using Norovirus as the reference pathogen and enterococci as the reference faecal indicator. The contribution made by each source to the total waterbody volume, indicator density, pathogen density, and illness risk was estimated for a number of scenarios that accounted for pathogen and indicator inactivation based on the age of the effluent (source-to-receptor), possible sedimentation of microorganisms, and the addition of a non-pathogenic source of faecal indicators (such as old sediments or an animal population with low occurrence of human-infectious pathogens). The waterbody indicator density was held constant at 35 CFU 100 mL(-1) enterococci to compare results across scenarios. For the combinations evaluated, either the untreated sewage or the non-pathogenic source of faecal indicators dominated the recreational waterbody enterococci density assuming a culture method. In contrast, indicator density assayed by qPCR, pathogen density, and bather gastrointestinal illness risks were largely dominated by secondary disinfected municipal wastewater, with untreated sewage being increasingly less important as the faecal indicator load increased from a non-pathogenic source. The results support the use of a calibrated qPCR total enterococci indicator, compared to a culture-based assay, to index infectious human enteric viruses released in treated human wastewater, and illustrate that the source contributing the majority of risk in a mixture may be overlooked when only assessing faecal indicators by a culture-based method.
Inactivation of indicators and pathogens in cattle feedlot manures and compost as determined by molecular and culture assays
Publisher: Oxford University Press (OUP)
Date: 15-04-2011
DOI: 10.1111/J.1574-6941.2011.01098.X
Abstract: Accurate and conservative information about pathogen inactivation rates is needed as the basis for safe manure management on beef cattle feedlots. The survival of indicators and pathogens in faecal pen manure, stockpiled manure and manure compost was measured with autochthonous indicator bacteria (Escherichia coli, Clostridium perfringens, enterococci, total coliforms) and pathogens (Listeria monocytogenes, C ylobacter jejuni) using culture and/or real-time quantitative PCR (qPCR) methods. Additionally, the manures were incubated at 20, 37, 50 and 60 °C in microcosms to quantify the persistence of autochthonous microorganisms and selected process performance surrogates (Clostridium sporogenes, green fluorescent protein-labelled E. coli and L. monocytogenes). Estimated qPCR cell counts indicated that up to four orders of magnitude more target cells were present compared with the culturable counts. Corresponding T(90) estimates were up to sixfold higher. This study demonstrates the benefits of nucleic acid-based quantification of pathogen inactivation in cattle manures and concludes that the concurrent analysis of microorganisms by molecular and culture methods provides complementary value.
Implementing sustainable water and sanitation projects in rural, developing communities
Publisher: Practical Action Publishing
Date: 2014
Overview of issues for water bacterial pathogens
Publisher: Michigan State University
Date: 2019
Genome sequence and analysis of the Irish potato famine pathogen Phytophthora infestans
Publisher: Springer Science and Business Media LLC
Date: 09-2009
DOI: 10.1038/NATURE08358
Abstract: Phytophthora infestans is the most destructive pathogen of potato and a model organism for the oomycetes, a distinct lineage of fungus-like eukaryotes that are related to organisms such as brown algae and diatoms. As the agent of the Irish potato famine in the mid-nineteenth century, P. infestans has had a tremendous effect on human history, resulting in famine and population displacement. To this day, it affects world agriculture by causing the most destructive disease of potato, the fourth largest food crop and a critical alternative to the major cereal crops for feeding the world's population. Current annual worldwide potato crop losses due to late blight are conservatively estimated at $6.7 billion. Management of this devastating pathogen is challenged by its remarkable speed of adaptation to control strategies such as genetically resistant cultivars. Here we report the sequence of the P. infestans genome, which at approximately 240 megabases (Mb) is by far the largest and most complex genome sequenced so far in the chromalveolates. Its expansion results from a proliferation of repetitive DNA accounting for approximately 74% of the genome. Comparison with two other Phytophthora genomes showed rapid turnover and extensive expansion of specific families of secreted disease effector proteins, including many genes that are induced during infection or are predicted to have activities that alter host physiology. These fast-evolving effector genes are localized to highly dynamic and expanded regions of the P. infestans genome. This probably plays a crucial part in the rapid adaptability of the pathogen to host plants and underpins its evolutionary potential.
Evaluation of Bacteroides fragilisGB-124 bacteriophages as novel human-associated faecal indicators in the United States
Publisher: Oxford University Press (OUP)
Date: 12-04-2014
DOI: 10.1111/LAM.12252
Abstract: Phages infecting human-associated Bacteroides fragilis (GB-124 phages) have been employed in the European Union (EU) to identify human faecal pollution, but their utility for the United States was unclear. Primary sewage s les were collected seasonally from seven wastewater treatment plants (WWTP) across the continental United States, and more time-intensive s ling was conducted at local WWTPs. All s les were assayed for plaque-forming units (PFU) of GB-124 phages, somatic and FRNA-specific coliphages, as well as adenoviruses (by quantitative PCR [qPCR]). Animal faecal s les (>250) from 14 different species were tested for the presence of the three phage groups. GB-124 phages were consistently detected in sewage (10-10(2) PFU ml(-1) ), but not in animal faeces. While density estimates of both coliphages in sewage were approximately one order of magnitude higher than GB-124 phages, they were both randomly detected in animal faecal s les (10(2) -10(5) g(-1) dry weight). Stability of all three phages was inversely proportional to temperature persistence was greatest at 5°C compared to 20 and 35°C, where no phages were detectable after a week. In summary, GB-124 phages appear to be a feasible alternative indicator organism and benefit from being sewage associated, while providing an inexpensive detection technique for infectious virions. Bacteroides fragilis GB-124 phages appear to be restricted to human sewage sources in the United States, being absent from 264 animal faecal s les from 14 different species and present in approx. 90% (34/38) of primary sewage effluent s les collected across the country. Although somatic and F-specific coliphages were present in sewage s les at higher densities, unlike GB-124 phages, both coliphage types were also detected in animal faecal s les. Hence, GB-124 phages may prove to be a useful novel indicator group for human faecal pollution in the continental United States.
Research findings: What utility managers need to know
Publisher: Wiley
Date: 2012
Differential bacterial predation by free-living amoebae may result in blooms of legionella in drinkingwater systems
Publisher: MDPI AG
Date: 15-01-2021
DOI: 10.3390/MICROORGANISMS9010174
Abstract: Intracellular growth of pathogenic Legionella in free-living amoebae (FLA) results in the critical concentrations that are problematic in engineered water systems (EWS). However, being amoeba-resistant bacteria (ARB), how Legionella spp. becomes internalized within FLA is still poorly understood. Using fluorescent microscopy, we investigated in real-time the preferential feeding behavior of three water-related FLA species, Willaertia magna, Acanthamoeba polyphaga, and Vermamoeba vermiformis regarding Legionella pneumophila and two Escherichia coli strains. Although all the studied FLA species supported intracellular growth of L. pneumophila, they avoided this bacterium to a certain degree in the presence of E. coli and mostly fed on it when the preferred bacterial food-sources were limited. Moreover, once L. pneumophila were intracellular, it inhibited digestion of co-occurring E. coli within the same trophozoites. Altogether, based on FLA–bacteria interactions and the shifts in microbial population dynamics, we propose that FLA’s feeding preference leads to an initial growth of FLA and depletion of prey bacteria, thus increases the relative abundance of Legionella and creates a “forced-feeding” condition facilitating the internalization of Legionella into FLA to initiate the cycles of intracellular multiplication. These findings imply that monitoring of FLA levels in EWS could be useful in predicting possible imminent high occurrence of Legionella.
Microbial risk implications of rainfall-induced runoff events entering a reservoir used as a drinking-water source
Publisher: IWA Publishing
Date: 12-2007
Environmental (Saprozoic) Pathogens of Engineered Water Systems: Understanding Their Ecology for Risk Assessment and Management
Publisher: MDPI AG
Date: 19-06-2015
Impact of drinking water conditions and copper materials on downstream biofilm microbial communities and Legionella pneumophila colonization
Publisher: Oxford University Press (OUP)
Date: 07-07-2014
DOI: 10.1111/JAM.12578
Abstract: This study examined the impact of pipe materials and introduced Legionella pneumophila on downstream Leg. pneumophila colonization and microbial community structures under conditions of low flow and low chlorine residual. CDC biofilm(™) reactors containing either unplasticized polyvinylchloride (uPVC) or copper (Cu) coupons were used to develop mature biofilms on Norprene(™) tubing effluent lines to simulate possible in-premise biofilm conditions. The microbial communities were characterized through 16S and 18S rRNA gene clone libraries and Leg. pneumophila colonization was determined via specific qPCR assays. The Cu significantly decreased downstream microbial ersity, approximately halved bacterial and eukaryotic abundance, with some groups only detected in uPVC-reactor tubing biofilms. However, some probable amoeba-resisting bacteria (ARB) like Mycobacterium spp. and Rhodobacteraceae were significantly more abundant in the Cu than uPVC-reactor tubing biofilms. In particular, Leg. pneumophila only persisted (postinoculation) within the Cu-reactor tubing biofilms, and the controlled low chlorine residue and water flow conditions led to a general high abundance of possible free-living protozoa in all tubing biofilms. The higher relative abundance of ARB-like sequences from Cu-coupons vs uPVC may have been promoted by amoebal selection and subsequent ARB protection from Cu inhibitory effects. Copper pipe and low flow conditions had significant impact on downstream biofilm microbial structures (on plastic pipe) and the ability for Leg. pneumophila colonization post an introduction event. This is the first report that compares the effects of copper and uPVC materials on downstream biofilm communities grown on a third (Norprene(™)) surface material. The downstream biofilms contained a high abundance of free-living amoebae and ARB, which may have been driven by a lack of residual disinfectant and periodic stagnant conditions. Given the prevalence of Cu-piping in buildings, there may be increased risk from drinking water exposures to ARB following growth on pipe/fixture biofilms within premise drinking water systems.
Extended persistence of general and cattle-associated fecal indicators in marine and freshwater environment
Publisher: Elsevier BV
Date: 02-2019
DOI: 10.1016/J.SCITOTENV.2018.09.108
Abstract: Fecal contamination of recreational waters with cattle manure can pose a risk to public health due to the potential presence of various zoonotic pathogens. Fecal indicator bacteria (FIB) have a long history of use in the assessment of recreational water quality, but FIB quantification provides no information about pollution sources. Microbial source tracking (MST) markers have been developed in response to a need to identify pollution sources, yet factors that influence their decay in ambient waters are often poorly understood. We investigated the influence of water type (freshwater versus marine) and select environmental parameters (indigenous microbiota, ambient sunlight) on the decay of FIB and MST markers originating from cattle manure. Experiments were conducted in situ using a submersible aquatic mesocosm containing dialysis bags filled with a mixture of cattle manure and ambient water. Culturable FIB (E. coli, enterococci) were enumerated by membrane filtration and general fecal indicator bacteria (GenBac3, Entero1a, EC23S857) and MST markers (Rum2Bac, CowM2, CowM3) were estimated by qPCR. Water type was the most significant factor influencing decay (three-way ANOVA, p: 0.006 to <0.001), although the magnitude of the effect differed among microbial targets and over time. The presence of indigenous microbiota and exposure to sunlight were significantly correlated (three-way ANOVA, p: 0.044 to <0.001) with decay of enterococci and CowM2, while E. coli, EC23S857, Rum2Bac, and CowM3 (three-way ANOVA, p: 0.044 < 0.001) were significantly impacted by sunlight or indigenous microbiota. Results indicate extended persistence of both cultivated FIB and genetic markers in marine and freshwater water types. Findings suggest that multiple environmental stressors are important determinants of FIB and MST marker persistence, but their magnitude can vary across indicators. Selective exclusion of natural aquatic microbiota and/or sunlight typically resulted in extended survival, but the effect was minor and limited to select microbial targets.
Modeling virus inactivation on salad crops using microbial count data
Publisher: Wiley
Date: 12-2001
Abstract: Microbial counts of the persistent Bacteroides fragilis bacteriophage B40-8 from a virus decay experiment conducted under glasshouse conditions were used to model the decay of viruses on wastewater-irrigated lettuce and carrot crops. The modeling approach applied gave specific consideration to the discrete nature of microbial count data. The experimental counts were best fit by a negative binomial distribution indicating highly dispersed distribution of viruses on lettuce and carrot crops following irrigation with wastewater. In addition, there was evidence for biphasic inactivation of viruses, signifying the presence of a persistent subpopulation of viruses that decayed slowly, resulting in virus accumulation on the crop surface over subsequent irrigations. Maximum likelihood estimates of initial and persistent subpopulation inactivation rates were 2.48 day(-1) and 0.51 day(-1) for lettuces and 0.84 day(-1) and 0.046 day(-1) for carrots. Maximum likelihood estimates of the persistent virus subpopulation size were 0.12% and 2% for lettuce and carrots, respectively.
Aeromonas
Publisher: Michigan State University
Date: 2019
GOBLET: The Global Organisation for Bioinformatics Learning, Education and Training
Publisher: Public Library of Science (PLoS)
Date: 09-04-2015
Dose–response algorithms for water-bornePseudomonas aeruginosafolliculitis
Publisher: Cambridge University Press (CUP)
Date: 02-10-2014
DOI: 10.1017/S0950268814002532
Abstract: We developed two dose–response algorithms for P. aeruginosa pool folliculitis using bacterial and lesion density estimates, associated with undetectable, significant, and almost certain folliculitis. Literature data were fitted to Furumoto & Mickey's equations, developed for plant epidermis-invading pathogens: N l = A ln(1 + BC ) (log-linear model) P inf = 1−e (− r c C ) (exponential model), where A and B are 2.51644 × 10 7 lesions/m 2 and 2.28011 × 10 −11 c.f.u./ml P. aeruginosa , respectively C = pathogen density (c.f.u./ml), N l = folliculitis lesions/m 2 , P inf = probability of infection, and r C = 4·3 × 10 −7 c.f.u./ml P. aeruginosa . Outbreak data indicates these algorithms apply to exposure durations of 41 ± 25 min. Typical water quality benchmarks (≈10 −2 c.f.u./ml) appear conservative but still useful as the literature indicated repeated detection likely implies unstable control barriers and bacterial bloom potential. In future, culture-based outbreak testing should be supplemented with quantitative polymerase chain reaction and organic carbon assays, and quantification of folliculitis aetiology to better understand P. aeruginosa risks.
Prioritisation of catchment management in the Sydney catchment - construction of a pathogen budget
Publisher: IWA Publishing
Date: 04-2004
DOI: 10.2166/WS.2004.0025
Abstract: A methodology has been developed to apply the materials budget concept, used in sediment and nutrient studies, to construct a pathogen budget for drinking water catchments, taking into consideration pathogen origin, deposition, inactivation and movement within a catchment. These processes can be described in terms of stocks (pathogens) and flows (movement of stocks). In south-eastern Australia, the majority of pathogen loading to major tributaries was predicted to occur during and after high intensity rainfall events where in-stream resuspension was not of great relative importance. In contrast, during dry weather the transit time within the studied catchment was sufficiently long that in-stream processes became relatively important. Total pathogen unit (TPU) budgets were constructed for the parasitic protozoa Cryptosporidium and Giardia. This approach enables water utility managers to identify those catchment segments and processes that are contributing or removing the greatest load of pathogens, and thus where management options will be most effective. With improved knowledge of pathogen ecology this approach can be further refined to provide budgets of infectious pathogen units (IPU), more directed to public health risk endpoints.
NMR confirmation of an alkali-insoluble glucan from Kluyveromyces marxianus cultivated on a lactose-based medium
Publisher: Springer Science and Business Media LLC
Date: 2003
Pathogen monitoring offers questionable protection against drinking-water risks: a QMRA (Quantitative Microbial Risk Analysis) approach to assess management strategies (vol 54, pg 261, 2005)
Publisher: IWA Publishing
Date: 12-2006
Eukaryotic diversity in premise drinking water using 18S rDNA sequencing: implications for health risks (vol 20, pg 6351, 2013)
Publisher: Springer Science and Business Media LLC
Date: 02-03-2014
Interactions of Pseudomonas aeruginosa with Acanthamoeba polyphaga Observed by Imaging Flow Cytometry
Publisher: Wiley
Date: 15-04-2019
DOI: 10.1002/CYTO.A.23768
Abstract: Pseudomonas aeruginosa is a Gram-negative bacterium that is abundant in the environment and water systems, with strains that cause serious infections, especially in patients with compromised immune systems. In times of stress or as part of its natural life cycle, P. aeruginosa can adopt a viable but not culturable (VBNC) state, which renders it undetectable by current conventional food and water testing methods and makes it highly resistant to antibiotic treatment. Specific conditions can resuscitate these coccoid VBNC P. aeruginosa cells, which returns them to their active, virulent rod-shaped form. Underreporting the VBNC cells of P. aeruginosa by standard culture-based methods in water distribution systems may therefore pose serious risks to public health. As such, being able to accurately detect and quantify the presence of VBNC P. aeruginosa, especially in a hospital setting, is of critical importance. Herein, we describe a method to analyze VBNC P. aeruginosa using imaging flow cytometry. With this technique, we can accurately distinguish between active and VBNC forms. We also show here that association of VBNC P. aeruginosa with Acanthamoeba polyphaga results in resuscitation of P. aeruginosa to an active form within 2 h. Our approach could provide an alternative, reliable detection method of VBNC P. aeruginosa when coupled with species-specific staining. Most importantly, our experiments demonstrate that the coculture with amoebae can lead to a resuscitation of P. aeruginosa of culturable morphology after only 2 h, indicating that VBNC P. aeruginosa could potentially resuscitate in piped water (healthcare) environments colonized with amoebae. © 2019 International Society for Advancement of Cytometry.
Improving nitrogen removal in an IFAS nitritation–anammox reactor treating lagoon supernatant by manipulating biocarrier filling ratio and hydraulic retention time
Publisher: Elsevier BV
Date: 12-2019
Editorial: Important news about this journal
Publisher: IWA Publishing
Date: 03-2021
DOI: 10.2166/WST.2021.000
Vertical response of microbial community and degrading genes to petroleum hydrocarbon contamination in saline alkaline soil
Publisher: Elsevier BV
Date: 07-2019
DOI: 10.1016/J.JES.2019.02.001
Abstract: A column microcosm was conducted by amending crude oil into Dagang Oilfield soil to simulate the bioremediation process. The dynamic change of microbial communities and metabolic genes in vertical depth soil from 0 to 80 cm were characterized to evaluate the petroleum degradation potential of indigenous microorganism. The influence of environmental variables on the microbial responds to petroleum contamination were analyzed. Degradation extent of 42.45% of n-alkanes (C8-C40) and 34.61% of 16ΣPAH were reached after 22 weeks. Relative abundance of alkB, nah, and phe gene showed about 10-fold increment in different depth of soil layers. Result of HTS profiles demonstrated that Pseudomonas, Marinobacter and Lactococcus were the major petroleum-degrading bacteria in 0-30 and 30-60 cm depth of soils. Fusarium and Aspergillus were the dominant oil-degrading fungi in the 0-60 cm depth of soils. In 60-80 cm deep soil, anaerobic bacteria such as Bacteroidetes, Lactococcus, and Alcanivorax played important roles in petroleum degradation. Redundancy analysis (RDA) and correlation analysis demonstrated that petroleum hydrocarbons (PHs) as well as soil salinity, clay content, and anaerobic conditions were the dominant effect factors on microbial community compositions in 0-30, 30-60, and 60-80 cm depth of soils, respectively.
Antimicrobial Resistance
Publisher: Michigan State University
Date: 2019
An Environmental Science and Engineering Framework for Combating Antimicrobial Resistance
Publisher: Mary Ann Liebert Inc
Date: 10-2018
Differential Decay of Enterococci and Escherichia coli Originating from Two Fecal Pollution Sources
Publisher: American Society for Microbiology
Date: 04-2013
DOI: 10.1128/AEM.03781-12
Abstract: Using in situ subtropical aquatic mesocosms, fecal source (cattle manure versus sewage) was shown to be the most important contributor to differential loss in viability of fecal indicator bacteria (FIB), specifically enterococci in freshwater and Escherichia coli in marine habitats. In this study, sunlight exposure and indigenous aquatic microbiota were also important contributors, whose effects on FIB also differed between water types.
From the lab to full-scale SBR operation: treating high strength and variable industrial wastewaters
Publisher: IWA Publishing
Date: 02-2001
Abstract: This paper describes the path taken from client objectives through laboratory studies and detailed design to full-scale SBR operation and current research. Conventional municipal design principles have often been used to develop treatment processes for industrial wastewaters. The use of scientific trials to test design criteria offers the client a “tailor made” design fit for their particular wastewater character. In this project, a waste management company wished to upgrade their physical-chemical treatment plant to incorporate a biological reactor for treating a range of industrial wastewaters. Laboratory-scale trials were undertaken to determine appropriate design criteria for a full-scale biological process. These laboratory studies indicated that conventional design criteria were not appropriate and that a SBR configuration was optimal compared with an IDAR configuration. It was also found that a novel fungal:bacterial mixed liquor consortium developed, resulting in good effluent quality and settling properties. The treatment plant was able to be constructed and operational within a tight timeframe and budget, allowing the client to take advantage of a commercial opportunity. The plant has been operating since 1997 and meets its discharge conditions. By combining scientific studies with engineering principles, the end-user obtained a complete treatment plant to meet their specific needs. A further benefit of the laboratory trials is current research into the development of a fungal:bacterial SBR to treat industrial wastewaters. This offers ongoing knowledge to the operational full-scale SBR.
Importance of controlling phosphate concentration in nitritation–anammox reactor operation
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9EW00203K
Abstract: The effect of phosphate on anaerobic ammonium oxidation (anammox) was investigated in an integrated fixed film activated sludge-sequencing batch reactor (IFAS-SBR) treating raw digester sludge thickening lagoon supernatants before and after Ostara® treatment (for phosphorus recovery).
Persistence of infectious Enterovirus within free-living amoebae – A novel waterborne risk pathway?
Publisher: Elsevier BV
Date: 11-2018
DOI: 10.1016/J.WATRES.2018.07.023
Abstract: Free-living amoebae (FLA) are phagocytic protozoa found in natural and engineered water systems. They can form disinfectant-resistant cysts, which can harbor various human pathogenic bacteria, therefore providing them with a means of environmental persistence and dispersion through water distribution and other engineered water systems. The association of FLA with human viruses has been raised, but the limited data on the persistence of infectious virions within amoebae leaves this aspect unresolved. Enteroviruses can cause a wide range of illness and replicate in human respiratory and gastrointestinal tracts, both of which could be exposed through contact with contaminated waters if virus detection and removal are compromised by virion internalization in free-living protozoa. This is especially problematic for high-risk contaminants, such as coxsackieviruses, representative members of the Enterovirus genus that are likely infectious at low doses and cause a variety of symptoms to a vulnerable portion of the population (particularly infants). To investigate Enterovirus persistence within free-living amoebae we co-cultured an infectious clinical coxsackievirus B5 (CVB5) isolate, with the commonly reported tap water amoeba Vermamoeba vermiformis, after which we tracked virus localization and persistence in co-culture over time through a combination of advanced imaging, molecular and cell culture assays. Our results clearly demonstrate that infectious CVB5 can persist in all life stages of the amoebae without causing any visible injury to them. We also demonstrated that the amoeba generated vesicles containing virions that were expelled into the bulk liquid surroundings, a finding previously described for FLA-bacteria interactions, but not for FLA and human pathogenic viruses. Therefore, our findings suggest that the ability of CVB5 to persist in V. vermiformis could be a novel waterborne risk pathway for the persistence and dispersion of infectious human enteric viruses through water systems.
Recovery and Enumeration of Cryptosporidium parvum from Animal Fecal Matrices
Publisher: American Society for Microbiology
Date: 05-2003
DOI: 10.1128/AEM.69.5.2842-2847.2003
Abstract: Accurate quantification of Cryptosporidium parvum oocysts in animal fecal deposits on land is an essential starting point for estimating watershed C. parvum loads. Due to the general poor performance and variable recovery efficiency of existing enumeration methods, protocols were devised based on initial dispersion of oocysts from feces by vortexing in 2 mM tetrasodium pyrophosphate, followed by immunomagnetic separation. The protocols were validated by using an internal control seed preparation to determine the levels of oocyst recovery for a range of fecal types. The levels of recovery of 10 2 oocysts from cattle feces (0.5 g of processed feces) ranged from 31 to 46%, and the levels of recovery from sheep feces (0.25 g of processed feces) ranged from 21% to 35%. The within-s le coefficients of variation for the percentages of recovery from five replicates ranged from 10 to 50%. The ranges for levels of recovery of oocysts from cattle, kangaroo, pig, and sheep feces (juveniles and adults) collected in a subsequent watershed animal fecal survey were far wider than the ranges predicted by the validation data. Based on the use of an internal control added to each fecal s le, the levels of recovery ranged from 0 to 83% for cattle, from 4 to 62% for sheep, from 1 to 42% for pigs, and from 40 to 73% for kangaroos. Given the variation in the levels of recovery of oocysts from different fecal matrices, it is recommended that an internal control be added to at least one replicate of every fecal s le analyzed to determine the percentage of recovery. Depending on the animal type and based on the lowest approximate percentages of recovery, between 10 and 100 oocysts g of feces −1 must be present to be detected.
Towards risk assessment for antibiotic resistant pathogens in recycled water: a systematic review and summary of research needs
Publisher: Wiley
Date: 22-10-2021
Abstract: Risk assessment is critical for identifying target concentrations of antibiotic resistant pathogens necessary for mitigating potential harmful exposures associated with water reuse. However, there is currently limited available data characterizing the concentrations of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) in recycled water to support robust efforts at risk assessment. The objective of this systematic review was to identify and synthesize the existing literature documenting the presence and abundance of ARB and ARGs in recycled water. In addition, this review identifies best practices and explores monitoring targets for studying ARB and ARGs in recycled water to guide future work and identifies key research needs aimed at better supporting quantitative microbial risk assessment focused on recycled water and antibiotic resistance. Future efforts to collect data about ARB and ARG prevalence in recycled water should report concentration data per unit volume. S le metadata should also be provided, including a description of treatment approach, a description of planned water uses (e.g., potable, irrigation), methods for conveyance to the point of use, and available physicochemical water quality data. Additional research is needed aimed at identifying recommended ARB and ARG monitoring targets and for developing approaches to incorporate metagenomic data into risk assessment.
Tenets of a holistic approach to drinking water-associated pathogen research, management, and communication
Publisher: Elsevier BV
Date: 03-2022
Quantitative Bayesian predictions of source water concentration for QMRA from presence/absence data for E. coli O157:H7
Publisher: IWA Publishing
Date: 06-2009
DOI: 10.2166/WST.2009.264
Abstract: A hierarchical Bayesian framework was applied for describing variability in pathogen concentration (with associated uncertainty) from presence/absence observations for E. coli O157:H7. Laboratory spiking experiments (method performance) and environmental s le assays were undertaken for a surface drinking water source in France. The concentration estimates were strongly dependent upon the assumed statistical model used (gamma, log-gamma or log-gamma constrained), highlighting the need for a solid theoretical basis for model choice. Bayesian methods facilitate the incorporation of additional data into the statistical analysis this was illustrated using faecal indicator results of E. coli (Colilert®) to reduce the posterior parameter uncertainty and improve model stability. While conceptually simple, application of these methods is still specialised, hence there is a need for the development of data analysis tools to make Bayesian simulation techniques more accessible for QMRA practitioners.
Response of microbial community and catabolic genes to simulated petroleum hydrocarbon spills in soils/sediments from different geographic locations
Publisher: Oxford University Press (OUP)
Date: 11-09-2017
DOI: 10.1111/JAM.13549
Abstract: Study the response of microbial communities and selected petroleum hydrocarbon (PH)-degrading genes on simulated PH spills in soils/sediments from different geographic locations. A microcosm experiment was conducted by spiking mixtures of petroleum hydrocarbons (PHs) to soils/sediments collected from four different regions of China, including the Dagang Oilfield (DG), Sand of Bohai Sea (SS), Northeast China (NE) and Xiamen (XM). Changes in bacterial community and the abundance of PH-degrading genes (alkB, nah and phe) were analysed by denaturing gradient electrophoresis (DGGE) and qPCR, respectively. Degradation of alkanes and PAHs in SS and NE materials were greater (P < 0·05) than those in DG and XM. Clay content was negatively correlated with the degradation of total alkanes by 112 days and PAHs by 56 days, while total organic carbon content was negatively correlated with initial degradation of total alkanes as well as PAHs. Abundances of alkB, nah and phe genes increased 10- to 100-fold and varied by soil type over the incubation period. DGGE fingerprints identified the dominance of α-, β- and γ-Proteobacteria (Gram -ve) and Actinobacteria (Gram +ve) bacteria associated with degradation of PHs in the materials studied. The geographic ergence resulting from the heterogeneity of physicochemical properties of soils/sediments appeared to influence the abundance of metabolic genes and community structure of microbes capable of degrading PHs. When developing practical in-situ bioremediation approaches for PHs contamination of soils/sediment, appropriate microbial community structures and the abundance of PH-degrading genes appear to be influenced by geographic location.
THE HEALTH OF SYDNEY SURFERS - AN EPIDEMIOLOGIC-STUDY
Publisher: IWA Publishing
Date: 02-1993
Abstract: This study forms part of a three year prospective cohort research project which began with a pilot trial in the summer of 1989/1990. The study proper will span the summers of 1990/91, 1991/92 and 1992/93. In response to environmental concerns about sewage ocean outfalls, the Water Board commissioned this study of recreational use of six popular surfing beaches located north and south of Sydney Harbour. A survey s le of 2003 recruits was enrolled on which 43,175 swimming events were recorded. Of these, 5879 (14%) had possibly attributable illness. A rise in relative risks was noted for total illness and respiratory illness but not for gastrointestinal illness. The relative risks for total illness in males rose from 1.79 in high frequency beach swimmers to 2.26 when high frequency beach swimming was combined with swimming at non-ocean sites. Females showed an increase in reported illness when beach swimming was combined with non-ocean swimming. This study lends no support to the concept of correlating health risk in swimmers with threshold levels of currently used bacterial indicator organisms. The value of further exploring the role of Clostridium perfringens as an indicator organism is supported.
Enteric virions and microbial biofilms - a secondary source of public health concern?
Publisher: IWA Publishing
Date: 08-2003
Abstract: Through their many sorption sites, microbial biofilms can accumulate both organic and inorganic particulate and colloidal material from bulk water environments. An application of such first principles to the ecology of “biocolloidal” enteric virions would suggest that they too may be concentrated by biofilms in a similar way. Though previous studies have isolated human gastrointestinal (enteric) virions from microbial biofilms, the exact human health significance of this has been neither fully investigated nor completely understood. Through an assessment of the location, accumulation and persistence of model enteric virions (φX174, MS2 and B40-8 bacteriophages as well as 20 nm fluorescent latex microspheres) within biofilms, the aim of the current study was to investigate whether the interaction of enteric virions with distribution pipe biofilms could provide a secondary source of public health concern to consumers. Model enteric virions were found to be incorporated into biofilms at concentrations representing 1% of those present in the adjacent bulk water environment. A sub-population (0.01%) of these persisted throughout an experimental period of 30 days, inferring their potential to accumulate over time. Furthermore, model enteric virions were partitioned into bacterial microcolonies, environments where biofilm bacteria can persist and re-grow, even in the presence of “acceptable” levels of disinfection. A risk model for enteric virion accumulation and release from distribution pipe biofilms suggested that associated risks may exceed USEPA benchmark values. These findings could have wide-reaching implications in water treatment and distribution strategies, and necessitate a re-appraisal of current water guideline values.
Review of multi-criteria decision aid for integrated sustainability assessment of urban water systems
Publisher: Informa UK Limited
Date: 12-2008
Conceptual model to inform Legionella–amoebae control, including the roles of extracellular vesicles in engineered water system infections
Publisher: Frontiers Media SA
Date: 18-05-2023
DOI: 10.3389/FCIMB.2023.1200478
Abstract: Extracellular vesicles (EVs or exosomes) are well described for bacterial pathogens associated with our gastrointestinal system, and more recently as a novel mechanism for environmental persistence, dissemination and infection for human enteric viruses. However, the roles played by EVs in the ancient arms race that continues between amoebae and one of their prey, Legionella pneumophila , is poorly understood. At best we know of intracellular vesicles of amoebae containing a mix of bacterial prey species, which also provides an enhanced niche for bacteriophage infection/spread. Free-living amoeba-associated pathogens have recently been recognized to have enhanced resistance to disinfection and environmental stressors, adding to previously understood (but for relatively few species of) bacteria sequestered within amoebal cysts. However, the focus of the current work is to review the likely impacts of large numbers of respiratory-sized EVs containing numerous L. pneumophila cells studied in pure and biofilm systems with mixed prey species. These encapsulated pathogens are orders of magnitude more resistant to disinfection than free cells, and our engineered systems with residual disinfectants could promote evolution of resistance (including AMR), enhanced virulence and EV release. All these are key features for evolution within a dead-end human pathogen post lung infection. Traditional single-hit pathogen infection models used to estimate the probability of infection/disease and critical environmental concentrations via quantitative microbial risk assessments may also need to change. In short, recognizing that EV-packaged cells are highly virulent units for transmission of legionellae, which may also modulate/avoid human host immune responses. Key data gaps are raised and a previous conceptual model expanded upon to clarify where biofilm EVs could play a role promoting risk as well as inform a more wholistic management program to proactively control legionellosis.
Total staphylococci as performance surrogate for greywater treatment
Publisher: Springer Science and Business Media LLC
Date: 05-2018
Viral risks associated with wastewater reuse: modeling virus persistence on wastewater irrigated salad crops
Publisher: IWA Publishing
Date: 06-2001
Abstract: A model for virus decay on lettuce and carrot crops has been derived as part of a comprehensive wastewater irrigation microbial risk assessment model under development. Results from the decay modeling indicated the presence of a very persistent sub-population of viruses evidenced by an initial rapid phase of decay followed by a very slow phase. In addition, virus counts fitted a negative binomial rather than Poisson distribution indicating over-dispersion. Hence the data indicated that viruses were not uniformly distributed over the surfaces of both crops. The aim of this paper was to investigate the implications of over-dispersion and the presence of a very persistent sub-population of viruses for assessing viral illness from the consumption of lettuces and carrots irrigated with secondary treated effluent. When over-dispersion or clumping of viruses was accounted for, a significant increase in the heterogeneity in the risk estimates arose. In addition, predicted infection rates were significantly underestimated if the presence of a persistent sub-population of viruses was not considered in the decay kinetics of the risk model. Hence, both viral clumping and persistence sub-populations should be accounted for in future risk assessments of enteric viruses associated with wastewater reuse.
Decreased efficacy of UV inactivation of Staphylococcus aureus after multiple exposure and growth cycles
Publisher: Elsevier BV
Date: 2019
DOI: 10.1016/J.IJHEH.2018.08.007
Abstract: UV disinfection is a relatively simple and cost-efficient disinfection method, especially for in-home greywater treatment. In this study, a bench scale experiment was performed using a LED collimated UV-C beam with a peak wavelength of 256 nm to determine if potentially pathogenic bacteria such as Staphylococcus aureus may become enriched in a semi-recirculating greywater system with UV as the sole disinfection step. A statistically significant (P < 0.001) decreasing trend in UV-C efficacy was observed between the 1st and 6th UV exposure-growth cycles of S. aureus (ATCC 25923), resulting in a 1.5 decrease in log
A comparison of methods and models for the analysis of water distribution pipe biofilms
Publisher: IWA Publishing
Date: 09-2002
DOI: 10.2166/WS.2002.0123
Abstract: The suitability of three experimental devices: biofilm reactors™ (BR), biofilm exos lers™ (BE), and modified robbins devices (MRD), for the analysis of water distribution pipe biofilms was examined in situ within an urban water distribution system (Rouse Hill Development Area, New South Wales). Stainless steel (ss) and unplasticized polyvinyl chloride (uPVC) coupons were conditioned with biofilm in each device for a period of 70 days. Biofilm removal techniques (sonication and stomaching) were evaluated and optimized for this study. A multiparametric quantification of biofilm biomass using total protein (NanoOrange™ protein determination) and carbohydrate (phenol-sulfuric assay) content, total number of bacterial cells (BacLight™ Live/Dead® Bacterial Viability Kit) and total number of heterotrophic bacteria (R2A plate counts) is proposed. The presence of biofilm-associated faecal indicator organisms (Enterococci, E. coli, somatic, F-RNA and B40-8 bacteriophages) was assayed for each biofilm homogenate. Variability both within and between biofilm devices was observed. Notwithstanding the shortcomings of the inherent heterogeneity observed with biofilm quantification, the relatively inexpensive biofilm devices were shown to yield reliable and comparable information on biofilm growth within an urban water distribution system. Furthermore, the multiparametric measurement of biofilm biomass was shown to provide a reliable and holistic quantification of distribution pipe biofilms.
Life cycle assessment of decentralized greywater treatment systems with reuse at different scales in cold regions
Publisher: Elsevier BV
Date: 2020
DOI: 10.1016/J.ENVINT.2019.105215
Abstract: Decentralized source-separated wastewater treatment systems offer an attractive alternative to conventional centralized wastewater treatment systems in various regions, yet few system analyses specifically address decentralized greywater treatment over different scales. Here we present a comparative life cycle assessment (LCA) and focus on global warming potential (GWP), eutrophication potential (EUP) and human health - carcinogenic potential (HHCP) of decentralized greywater management systems at different scales for a hypothetical community in a cold (winter) region. To provide a comparison between nature-based and engineered greywater treatment solutions, constructed wetlands (CW) and membrane bioreactors (MBR), respectively, were investigated at three different scales community (3500 person equivalent [PE]), neighborhood (350 PE) and household (a single household [up to 5 PE]). Conventional centralized wastewater treatment was also included as a business-as-usual (BAU) scenario. In the MBR scenarios, greywater reuse was also considered for multiple non-potable applications due to its high-quality effluent and subsurface garden irrigation was considered for reuse in the CW scenarios. For scenarios with the same treatment technology, larger scales reduced GWP, EUP and HHCP up to 57 kg CO
Fate and Transport of Surface Water Pathogens in Watersheds
Publisher: Informa UK Limited
Date: 07-2003
Flood and Infectious Disease Risk Assessment
Publisher: Springer Singapore
Date: 28-11-2019
Functional microbial diversity explains groundwater chemistry in a pristine aquifer
Publisher: Springer Science and Business Media LLC
Date: 24-06-2013
Abstract: The erse microbial populations that inhabit pristine aquifers are known to catalyze critical in situ biogeochemical reactions, yet little is known about how the structure and ersity of this subsurface community correlates with and impacts upon groundwater chemistry. Herein we examine 8,786 bacterial and 8,166 archaeal 16S rRNA gene sequences from an array of monitoring wells in the Mahomet aquifer of east-central Illinois. Using multivariate statistical analyses we provide a comparative analysis of the relationship between groundwater chemistry and the microbial communities attached to aquifer sediment along with those suspended in groundwater. Statistical analyses of 16S rRNA gene sequences showed a clear distinction between attached and suspended communities with iron-reducing bacteria far more abundant in attached s les than suspended, while archaeal clones related to groups associated with anaerobic methane oxidation and deep subsurface gold mines (ANME-2D and SAGMEG-1, respectively) distinguished the suspended community from the attached. Within the attached bacterial community, cloned sequences most closely related to the sulfate-reducing Desulfobacter and Desulfobulbus genera represented 20% of the bacterial community in wells where the concentration of sulfate in groundwater was high ( 0.2 mM), compared to only 3% in wells with less sulfate. Sequences related to the genus Geobacter , a genus containing ferric-iron reducers, were of nearly equal abundance (15%) to the sulfate reducers under high sulfate conditions, however their relative abundance increased to 34% when sulfate concentrations were 0.03 mM. Also, in areas where sulfate concentrations were .03 mM, archaeal 16S rRNA gene sequences similar to those found in methanogens such as Methanosarcina and Methanosaeta comprised 73–80% of the community, and dissolved CH 4 ranged between 220 and 1240 μM in these groundwaters. In contrast, methanogens (and their product, CH 4 ) were nearly absent in s les collected from groundwater s les with 0.2 mM sulfate. In the suspended fraction of wells where the concentration of sulfate was between 0.03 and 0.2 mM, the archaeal community was dominated by sequences most closely related to the ANME-2D, a group of archaea known for anaerobically oxidizing methane. Based on available energy (∆G A ) estimations, results varied little for both sulfate reduction and methanogenesis throughout all wells studied, but could favor anaerobic oxidation of methane (AOM) in wells containing minimal sulfate and dihydrogen, suggesting AOM coupled with H 2 -oxidizing organisms such as sulfate or iron reducers could be an important pathway occurring in the Mahomet aquifer. Overall, the results show several distinct factors control the composition of microbial communities in the Mahomet aquifer. Bacteria that respire insoluble substrates such as iron oxides, i.e. Geobacter , comprise a greater abundance of the attached community than the suspended regardless of groundwater chemistry. Differences in community structure driven by the concentration of sulfate point to a clear link between the availability of substrate and the abundance of certain functional groups, particularly iron reducers, sulfate reducers, methanogens, and methanotrophs. Integrating both geochemical and microbiological observations suggest that the relationships between these functional groups could be driven in part by mutualism, especially between ferric-iron and sulfate reducers.
DIGITAL MAPPING OF METAL-BEARING AMEBOCYTES IN TISSUE-SECTIONS OF THE PACIFIC OYSTER BY SCANNING MICROPHOTOMETRY
Publisher: Wiley
Date: 04-1985
The active bacterial community in a pristine confined aquifer
Publisher: American Geophysical Union (AGU)
Date: 09-2012
DOI: 10.1029/2011WR011568
Abstract: This study of the active bacteria residing in a pristine confined aquifer provides unexpected insights into the ecology of iron‐reducing and sulfate‐reducing bacteria in the subsurface. At 18 wells, we trapped the microbes that attached to aquifer sediment and used molecular techniques to examine the bacterial populations. We used multivariate statistics to compare the composition of bacterial communities among the wells with respect to the chemistry of the groundwater. We found groundwater at each well was considerably richer in ferrous iron than sulfide, indicating iron‐reducing bacteria should, by established criteria, dominate the sulfate reducers. Our results show, however, that areas where groundwater contains more than a negligible amount of sulfate ( .03 mM), populations related to sulfate reducers of the genera Desulfobacter and Desulfobulbus were of nearly equal abundance with putative iron reducers related to Geobacter , Geothrix , and Desulfuromonas. Whereas sulfate is a key discriminant of bacterial community structure, we observed no statistical relationship between the distribution of bacterial populations in this aquifer and the concentration of either ferrous iron or dissolved sulfide. These results call into question the validity of using the relative concentration of these two ions to predict the nature of bacterial activity in an aquifer. Sulfate reducers and iron reducers do not appear to be segregated into discrete zones in the aquifer, as would be predicted by the theory of competitive exclusion. Instead, we find the two groups coexist in the subsurface in what we suggest is a mutualistic relationship.
The importance of integrated fixed film activated sludge reactor and intermittent aeration in nitritation-anammox systems: Understanding reactor optimization for lagoon supernatant treatment
Publisher: Elsevier BV
Date: 04-2020
The role of biofilms and protozoa in legionella pathogenesis: Implications for drinking water
Publisher: Oxford University Press (OUP)
Date: 08-2009
DOI: 10.1111/J.1365-2672.2009.04208.X
Abstract: Current models to study Legionella pathogenesis include the use of primary macrophages and monocyte cell lines, various free-living protozoan species and murine models of pneumonia. However, there are very few studies of Legionella spp. pathogenesis aimed at associating the role of biofilm colonization and parasitization of biofilm microbiota and release of virulent bacterial cell/vacuoles in drinking water distribution systems. Moreover, the implications of these environmental niches for drinking water exposure to pathogenic legionellae are poorly understood. This review summarizes the known mechanisms of Legionella spp. proliferation within Acanthamoeba and mammalian cells and advocates the use of the amoeba model to study Legionella pathogenicity because of their close association with Legionella spp. in the aquatic environment. The putative role of biofilms and amoebae in the proliferation, development and dissemination of potentially pathogenic Legionella spp. is also discussed. Elucidating the mechanisms of Legionella pathogenicity development in our drinking water systems will aid in elimination strategies and procedural designs for drinking water systems and in controlling exposure to Legionella spp. and similar pathogens.
Eukaryotic diversity in premise drinking water using 18S rDNA sequencing: implications for health risks
Publisher: Springer Science and Business Media LLC
Date: 16-04-2013
DOI: 10.1007/S11356-013-1646-5
Abstract: The goal of this study was to characterize microbial eukaryotes over a 12-month period to provide insight into the occurrence of potential bacterial predators and hosts in premise plumbing. Nearly 6,300 partial 18S rRNA gene sequences from 24 hot (36.9-39.0 °C) and cold (6.8-29.1 °C) drinking water s les were analyzed and classified into major eukaryotic groups. Each major group, consisting of free-living amoebae (FLA) rotozoa, algae, copepods, dinoflagellates, fungi, nematodes, and unique uncultured eukaryotic sequences, showed limited ersity dominated by a few distinct populations, which may be characteristic of oligotrophic environments. Changes in the relative abundance of predators such as nematodes, copepods, and FLA appear to be related to temperature and seasonal changes in water quality. Sequences nearly identical to FLA such as Hartmannella vermiformis, Echinamoeba thermarmum, Pseudoparamoeba pagei, Protacanthamoeba bohemica, Platyamoeba sp., and Vannella sp. were obtained. In addition to FLA, various copepods, rotifers, and nematodes have been reported to internalize viral and bacterial pathogens within drinking water systems thus potentially serving as transport hosts implications of which are discussed further. Increasing the knowledge of eukaryotic occurrence and their relationship with potential pathogens should aid in assessing microbial risk associated with various eukaryotic organisms in drinking water.
Risk and governance in water recycling public acceptance revisited
Publisher: SAGE Publications
Date: 03-2006
Abstract: Public acceptance is often seen as a key reason why water-recycling technology is (accepted or) rejected. A common assumption is that projects fail because the general public is unable to comprehend specialist information about risk and the belief that if the public were better informed, they would accept change more readily. This article suggests that rhetoric about acceptance is counterproductive in progressing sustainability as it does not address issues relating to institutional arrangements and reinforces a dichotomy between expert and lay groups. Instead, it is argued that institutional change is needed to build opportunities for constructive public engagement. The failure to implement sustainable water use through recycling can be understood as the result of several factors including present cost structures for water, institutional conservatism, administrative fragmentation, and inadequate involvement of communities in planning. Achieving sustainable water use through recycling may require better coordination between agencies and integrated government policies.
Understanding anaerobic decolourisation of textile dye wastewater: mechanism and kinetics
Publisher: IWA Publishing
Date: 07-2000
Abstract: Worldwide, some 280,000 tons of textile dyes are discharged per annum. Degradation of the predominant highly soluble reactive dyes is poor within activated sludge plants, and instead requires anaerobic pretreatment for reductive cleavage of the chromogenic azo bond to precede aerobic degradation. The mechanism for the anaerobic reductive cleavage, which results in decolourisation, is not well understood. Further, thermophilic anaerobic pre-treatment has not been reported, although the wastewater is produced at high temperature (50–80°C). This project therefore aimed to compare decolourisation kinetics under mesophilic (35°C) and thermophilic (55°C) conditions and elucidate biotic and abiotic factors in the decolourisation of the dye, Reactive Red 235. Preliminary experiments indicated that acclimation of the up-flow anaerobic sludge blanket (UASB) biomass was unnecessary and there was no dye toxicity at expected wastewater concentrations (0.05–0.1g/L). Decolourisation of Reactive Red 235 was studied under batch conditions with intact and autoclaved biomass, and also using the pre-reduced supernatant from a spent culture (0.2 μm filtered). Based on HPLC identification of the dye and reaction products, first-order kinetics was observed and rate constants of –0.0096/min (thermophilic) and –0.0034/min (mesophilic) were estimated for intact, viable biomass. Abiotic decolourisation was 60–80% lower for the autoclaved s les, and under 12–35% lower for the filtered supernatant. Hence it may be concluded that active anaerobic cells give the most efficient and complete decolourisation, especially under thermophilic conditions. Nonetheless, abiotic reduction does occur and has implications for the design of a novel uncoupled reactor system.
Dispersion and Transport of Cryptosporidium Oocysts from Fecal Pats under Simulated Rainfall Events
Publisher: American Society for Microbiology
Date: 02-2004
DOI: 10.1128/AEM.70.2.1151-1159.2004
Abstract: The dispersion and initial transport of Cryptosporidium oocysts from fecal pats were investigated during artificial rainfall events on intact soil blocks (1,500 by 900 by 300 mm). Rainfall events of 55 mm h −1 for 30 min and 25 mm h −1 for 180 min were applied to soil plots with artificial fecal pats seeded with approximately 10 7 oocysts. The soil plots were ided in two, with one side devoid of vegetation and the other left with natural vegetation cover. Each combination of event intensity and duration, vegetation status, and degree of slope (5° and 10°) was evaluated twice. Generally, a fivefold increase ( P 0.05) in runoff volume was generated on bare soil compared to vegetated soil, and significantly more infiltration, although highly variable, occurred through the vegetated soil blocks ( P 0.05). Runoff volume, event conditions (intensity and duration), vegetation status, degree of slope, and their interactions significantly affected the load of oocysts in the runoff. Surface runoff transported from 10 0.2 oocysts from vegetated loam soil (25-mm h −1 , 180-min event on 10° slope) to up to 10 4.5 oocysts from unvegetated soil (55-mm h −1 , 30-min event on 10° slope) over a 1-m distance. Surface soil s les downhill of the fecal pat contained significantly higher concentrations of oocysts on devegetated blocks than on vegetated blocks. Based on these results, there is a need to account for surface soil vegetation coverage as well as slope and rainfall runoff in future assessments of Cryptosporidium transport and when managing pathogen loads from stock grazing near streams within drinking water watersheds.
Legionella pneumophila Transcriptional Response following Exposure to CuO Nanoparticles
Publisher: American Society for Microbiology
Date: 15-04-2013
DOI: 10.1128/AEM.03462-12
Abstract: Copper ions are an effective antimicrobial agent used to control Legionnaires' disease and Pontiac fever arising from institutional drinking water systems. Here, we present data on an alternative bactericidal agent, copper oxide nanoparticles (CuO-NPs), and its efficacy on Legionella pneumophila . In broth cultures, the CuO-NPs caused growth inhibition, which appeared to be concentration and exposure time dependent. The transcriptomic response of L. pneumophila to CuO-NP exposure was investigated by using a whole-genome microarray. The expression of genes involved in metabolism, transcription, translation, DNA replication and repair, and unknown/hypothetical proteins was significantly affected by exposure to CuO-NPs. In addition, expression of 21 virulence genes was also affected by exposure to CuO-NP and further evaluated by quantitative reverse transcription-PCR (qRT-PCR). Some virulence gene responses occurred immediately and transiently after addition of CuO-NPs to the cells and faded rapidly ( icmV , icmW , lepA ), while expression of other genes increased within 6 h ( ceg29 , legLC8 , legP , lem19 , lem24 , lpg1689 , and rtxA ), 12 h ( cegC1 , dotA , enhC , htpX , icmE , pvcA , and sidF ), and 24 h ( legP , lem19 , and ceg19 ), but for most of the genes tested, expression was reduced after 24 h of exposure. Genes like ceg29 and rtxA appeared to be the most responsive to CuO-NP exposures and along with other genes identified in this study may prove useful to monitor and manage the impact of drinking water disinfection on L. pneumophila .
A simple method for evaluating Cryptosporidium-specific antibodies used in monitoring environmental water samples
Publisher: Oxford University Press (OUP)
Date: 11-1997
DOI: 10.1046/J.1472-765X.1997.00237.X
Abstract: A simple method is described for the evaluation and quality control of Cryptosporidium-specific antibodies used in monitoring environmental water s les. Purified oocysts were fluorescently labelled with a test antibody at the appropriate concentration. Labelled oocysts were analysed using flow cytometry and a region was defined on a bivariate dotplot of fluorescence versus light scatter that enclosed all oocysts. Concentrates of environmental water s les that did not contain oocysts were then incubated with the test antibody and analysed using flow cytometry. The number of particles that appeared in the region defined for oocysts was recorded and was a measure of non-specific binding. The technique provides a simple, rapid and quantitative tool for both evaluating the binding specificity of test antibodies and optimizing s le staining conditions.
Effect of Disinfectant Exposure on Legionella pneumophila Associated with Simulated Drinking Water Biofilms: Release, Inactivation, and Infectivity
Publisher: American Chemical Society (ACS)
Date: 02-02-2017
Abstract: Legionella pneumophila, the most commonly identified causative agent in drinking water associated with disease outbreaks, can be harbored by and released from drinking water biofilms. In this study, the release of biofilm-associated L. pneumophila under simulated drinking water flow containing a disinfectant residual was examined. Meanwhile, the inactivation and infectivity (to amoebae) of the released L. pneumophila were studied. To simulate drinking water system conditions, biofilms were prepared under either disinfectant exposure (predisinfected biofilms) or disinfectant-free (untreated biofilms) conditions, respectively. For experiments with water flow containing a disinfectant to release the biofilm-associated L. pneumophila from these two types of biofilms, the L. pneumophila release kinetics values from predisinfected and untreated biofilms under flow condition were not statistically different (one-way ANOVA, p > 0.05). However, inactivation of the L. pneumophila released from predisinfected biofilms was 1-2 times higher and amoeba infectivity was 2-29 times lower than that from untreated biofilms. The higher disinfectant resistance of L. pneumophila released from untreated biofilms was presumably influenced by the detachment of a larger amount of biofilm material (determined by 16S rRNA qPCR) surrounding the released L. pneumophila. This study highlights the interaction among disinfectant residual, biofilms, and L. pneumophila, which provides guidelines to assess and control pathogen risk.
The use of a thermopilic anaerobic system for pretreatment of textile dye wastewater
Publisher: IWA Publishing
Date: 09-2000
Abstract: A thermophilic up-flow anaerobic sludge blanket (UASB) reactor was investigated for the decolouration of a synthetic textile wastewater. Textile wastewater is produced at high temperature and dyes are amenable to decolourisation under anaerobic conditions, however this is the first report of the use of such a thermophilic system to aid in the treatment of this wastewater. The decolouration efficiency and robustness of the thermophilic system were compared with a corresponding mesophilic anaerobic system to study the reduction of a selection of reactive dyes, the toxic effect of increasing influent dye concentration (up to 0.64 g.L-1), and the response during acclimation to high salinity conditions (up to 20 g.L-1 as sodium chloride) in three separate stages of experimentation. It was shown that compared with the mesophilic system, the thermophilic UASB treatment gave considerably higher dye decolouration with all the dyes tested, and under all operating conditions investigated. No loss in decolourisation potential was observed during an increase in influent dye concentration. However, toxicity effects were evident, noted by a decrease in COD removal and methane gas production. Acclimation to high salt concentrations also showed an adverse effect upon COD removal and gas production, however dye removal again remained virtually 100 % efficient.
Evidence for the evolution, clonal expansion and global dissemination of water treatment-resistant naturalized strains of Escherichia coli in wastewater
Publisher: Elsevier BV
Date: 06-2019
DOI: 10.1016/J.WATRES.2019.03.024
Abstract: We previously demonstrated the existence of naturalized strains of E. coli in wastewater and herein perform an in-depth comparative whole genome analysis of these strains (n = 17). Fourteen of the Canadian E. coli strains, isolated from geographically separated wastewater treatment plants, were virtually identical at the core genome and were ≥96% similar at the whole genome level, suggesting clonal-relatedness among these isolates. Remarkably, these strains were shown to be extremely similar to the genome of an E. coli isolated from wastewater in Switzerland, suggesting a global distribution of these strains. The genomes of three other Canadian wastewater strains were more erse but very similar to the genomes of E. coli isolates collected from U.S. wastewater s les. Based on maximum likelihood phylogenetic analysis, wastewater strains from Canada, the U.S. and Switzerland formed a clade separate from other known enteric phylogroups (i.e., A, B1, B2, D, E) and the cryptic clades. All Canadian, Swiss and U.S. wastewater strains possessed a common SNP biomarker pattern across their genomes, and a sub-population (i.e., 14 Canadian and 1 Swiss strain) also possessed a previously identified wastewater-specific marker known as uspC-IS30-flhDC element. Biochemical heat mapping of 518 categories of genes recapitulated phylogeny, with wastewater strains phenotypically clustering separately from enteric and cryptic clades. Wastewater strains were enriched for stress-response genes (i.e., nutrient acquisition/deprivation, DNA repair, oxidative stress, and UV resistance) - elements reflective of their environmental survival challenges. Wastewater strains were shown to carry a plethora of known antibiotic resistance (AR) genes, the patterns of which were remarkably similar among all Canadian, U.S. and Swiss wastewater strains. Virulence gene composition was also similar among all the wastewater strains, with an abundant representation of virulence genes commonly associated with urinary pathogenic E. coli (UPEC) as well as enterohemorrhagic (EHEC) E. coli. The remarkable degree of similarity between all wastewater strains from Canada, Switzerland and the U.S. suggests the evolution and global-dissemination of water treatment-resistant clone of E. coli. These finding, along with others, raise some important concerns about the potential for emergence of E. coli pathotypes resistant to water-treatment.
Editorial: Important news about this journal
Publisher: IWA Publishing
Date: 03-2021
Editorial: Important news about this journal
Publisher: IWA Publishing
Date: 03-2021
SCADA data and the quantification of hazardous events for QMRA
Publisher: IWA Publishing
Date: 09-2007
DOI: 10.2166/WH.2007.138
Abstract: The objective of this study was to assess the use of on-line monitoring to support the QMRA at water treatment plants studied in the EU MicroRisk project. SCADA data were obtained from three Catchment-to-Tap Systems (CTS) along with system descriptions, diary records, grab s le data and deviation reports. Particular attention was paid to estimating hazardous event frequency, duration and magnitude. Using Shewart and CUSUM we identified ‘change-points’ corresponding to events of between 10 min and & 1 month duration in timeseries data. Our analysis confirmed it is possible to quantify hazardous event durations from turbidity, chlorine residual and pH records and distinguish them from non-hazardous variability in the timeseries dataset. The durations of most ‘events’ were short-term (0.5–2.3 h). These data were combined with QMRA to estimate pathogen infection risk arising from such events as chlorination failure. While analysis of SCADA data alone could identify events provisionally, its interpretation was severely constrained in the absence of diary records and other system information. SCADA data analysis should only complement traditional water s ling, rather than replace it. More work on on-line data management, quality control and interpretation is needed before it can be used routinely for event characterization.
Pathogenic Escherichia coli in rural household container waters
Publisher: IWA Publishing
Date: 03-2013
DOI: 10.2166/WST.2013.677
Abstract: Plastic containers in the range of 5–20 L are widely used – especially in rural African settings – to collect, transport and store water for domestic use, including drinking, bathing and hygiene. The pathogen content of the waters in these containers has not been adequately characterized as yet. This paper presents the primary findings of a synoptic survey of drinking water quality s les from these containers and involved collection of bacterial indicator and pathogenicity gene data. In total, 571 s les of a variety of waters were taken in rural communities in South Africa and the Escherichia coli numbers measured. Of the E. coli positive s les, 46% (n = 148) were screened for the presence of E. coli pathogen gene markers. Though synoptic, the survey provided many insights into the issues that drove the study. Container use markedly degraded water quality as judged by indicator counts, even where improved water supply services were in place. Household container use also appeared to promote regrowth or contamination of containers with pathogenic E. coli strains. Polymerase chain reaction (PCR) analysis also showed that the ersity of potential pathogenic E. coli carrying virulence genes was great. All seven genes screened for (Ial, Stx1, Stx2, EaeA, Eagg, ST, LT) were found in the waters, alone or as mixtures (number of different combinations = 31) including those characteristic of the more dangerous invasive and haemorrhagic E. coli strains. Given the central role of containers in the management of water supply to rural communities, it is clear the microbiology of these waters requires much further characterization.
Of: microbial risks from wastewater irrigation of salad crops: a screening-level risk assessment
Publisher: Wiley
Date: 07-2002
ACETIC-ACID BACTERIAL BIOTA OF THE PINK SUGAR-CANE MEALYBUG, SACCHAROCOCCUS-SACCHARI, AND ITS ENVIRONS
Publisher: American Society for Microbiology
Date: 03-1990
DOI: 10.1128/AEM.56.3.707-712.1990
Abstract: Saccharococcus sacchari is the primary colonizer of the developing “sterile” tissue between the leaf sheath and stem of sugar cane. The honeydew secreted by the mealybugs is acidic (about pH 3) and supports an atypical epiphytic microbiota dominated by acetobacter-like bacteria and acidophilic yeast species. However, Erwinia and Leuconostoc species predominate within the leaf sheath pocket region when the mealybugs die out. The unidentified acetobacters were readily isolated from S. sacchari throughout its life cycle and from other genera of mealybugs on sugar cane and various other plants, both above and below ground. No other insect present on sugar cane was a significant vector of acetic acid bacteria. The major factors restricting microbial ersity within the environs of mealybugs were considered to be yeast activity along with bacterial production of acetic acid, ketogluconic acids, and gamma-pyrones, in association with their lowering of pH. The microbial products may aid in suppressing the attack by the parasitic mold Aspergillus parasiticus on mealybugs but could act as attractants for the predatory fruit fly Cacoxenus perspicax.
A systematic literature review on the socio-economic roles of waqf: evidence from organization of the Islamic cooperation (OIC) countries
Publisher: Emerald
Date: 15-10-2021
DOI: 10.1108/JIABR-01-2021-0028
Abstract: This paper aims to analyze the role of waqf in the socio-economic development of the organization of the Islamic Cooperation (OIC) countries. Various projects currently use waqf as an instrument for socio-economic development, as reported in the scholarly literature. This study will investigate this literature to explore trends in waqf studies and the role of this Islamic form of endowment in the socio-economic development of OIC countries. This systematic literature review focuses on peer-reviewed journals and data obtained from the Mendeley database using specific criteria to analyze the socio-economic developmental role of waqf in OIC countries from 2011‐2020. The socio-economic developmental role of waqf in OIC countries has been widely studied. In total, 68 academic articles were found that are relevant to themes of poverty alleviation, social welfare, entrepreneurship, education, health services and religious facilities. They reveal that the role of waqf in social welfare was the most discussed topic in the research. In addition, the majority of studies used an interview method to study waqf institutions in nine OIC countries. Furthermore, the number of publications on the theme has increased significantly every year, although the largest proportion occurred in unindexed journals. This study provides an overview of research trends in the socio-economic developmental role of waqf . Its results can provide practical input for waqf institutions as they encourage its practice in OIC countries, and for policymakers in formulating their management strategies to promote the role of waqf in the social and economic aspects of society. This paper reviews the current development of the socio-economic role of waqf in OIC countries. It will help researchers improve their understanding of this role. It will also provide waqf managers in OIC countries with adequate information on waqf projects which they can implement to achieve socio-economic development in their countries.
Development of a process-based model to predict pathogen budgets for the Sydney drinking water catchment
Publisher: IWA Publishing
Date: 11-2007
DOI: 10.2166/WH.2007.013
Abstract: Over 1.1 billion people in the world lack access to improved drinking water. Diarrheal and other waterborne diseases cause an estimated 2.2 million deaths per year. The Safe Water System (SWS) is a proven household water treatment intervention that reduces diarrheal disease incidence in users in developing countries. Because the SWS recommends the addition of sodium hypochlorite to unfiltered water sources, concerns have been raised about the potential long-term health effects of disinfection by-products to SWS users. This study investigated the production of trihalomethanes (THMs) in water treated with sodium hypochlorite from six sources used for drinking water in western Kenya. The turbidity values of these sources ranged from 4.23 NTU to 305 NTU. THM concentrations were analysed at 1, 8, and 24 hours after addition of sodium hypochlorite. No s le exceeded the World Health Organization (WHO) guideline values for any of the four THMs: chloroform, bromodichloromethane, dibromochloromethane, or bromoform. In addition, no s le exceeded the WHO additive total THM guideline value. These results clearly show that point-of-use chlorination of a variety of realistic source waters used for drinking did not lead to THM concentrations that pose a significant health risk to SWS users.
The Efficacy of Heat and Chlorine Treatment against Thermotolerant Acanthamoebae and Legionellae
Publisher: Informa UK Limited
Date: 09-2004
Toward a Universal Unit for Quantification of Antibiotic Resistance Genes in Environmental Samples
Publisher: American Chemical Society (ACS)
Date: 13-06-2023
Biofilms, thermophilic amoebae and Legionella pneumophila - A quantitative risk assessment for distributed water
Publisher: IWA Publishing
Date: 07-2004
Abstract: A simplistic quantitative microbial risk assessment (QMRA) based on the maximum risk curve (r = 1) was developed for Legionella within a water distribution system. Both biofilms and a thermophilic isolate of acanthamoebae were shown to increase the resistance of Legionella to conventional thermal disinfection by between one and two logs respectively. The level of risk presented to consumers was shown to exceed the USEPA 10-4 benchmark in many cases tested. This was caused, in part, by the sensitivity of the risk model but also through a lack of reliable dose-response data for Legionella. Notwithstanding this, the current study provided comparative information on the efficacy of conventional disinfection against Legionella. Combined chlorine was shown to reduce the risk of infection by as much as 1-log when compared to free chlorine, although thermal disinfection provided the most effective means of risk reduction. Biofilm detachment and the interaction of Legionella with acanthamoebae were two important ecological factors that significantly increased the risk of legionellosis, and thus should be further considered in the refinement of QMRA models.
A bench-scale system to study the composting of organic wastes
Publisher: Wiley
Date: 07-1982
Diversity and abundance of zoonotic pathogens and indicators in manures of feedlot cattle in Australia
Publisher: American Society for Microbiology
Date: 15-10-2010
DOI: 10.1128/AEM.01095-10
Abstract: The occurrence of 10 pathogens and three fecal indicators was assessed by quantitative PCR in manures of Australian feedlot cattle. Most s les tested positive for one or more pathogens. For the dominant pathogens C ylobacter jejuni , Listeria monocytogenes , Giardia spp., Cryptosporidium spp., and eaeA -positive Escherichia coli , 10 2 to 10 7 genome copies g −1 (dry weight) manure were recovered.
Municipal gravity sewers: An unrecognised source of nitrous oxide
Publisher: Elsevier BV
Date: 2014
DOI: 10.1016/J.SCITOTENV.2013.08.051
Abstract: Nitrous oxide (N2O) is a primary ozone-depleting substance and powerful greenhouse gas. N2O emissions from secondary-level wastewater treatment processes are relatively well understood as a result of intensive international research effort in recent times, yet little information exists to date on the role of sewers in wastewater management chain N2O dynamics. Here we provide the first detailed assessment of N2O levels in the untreated influent (i.e. sewer network effluent) of three large Australian metropolitan wastewater treatment plants. Contrary to current international (IPCC) guidance, results show gravity sewers to be a likely source of N2O. Results from the monitoring program revealed hydraulic flow rate as a strong driver for N2O generation in gravity sewers, with microbial processes (nitrification and possibly denitrification) implicated as the main processes responsible for its production. Results were also used to develop a presumptive emission factor for N2O in the context of municipal gravity sewers. Considering the discrepancy with current IPCC Guidelines, further work is warranted to assess the scale and dynamics of N2O production in sewers elsewhere.
Adaptation of anaerobic ammonium-oxidising consortium to synthetic coke-ovens wastewater
Publisher: Springer Science and Business Media LLC
Date: 07-2002
DOI: 10.1007/S00253-002-1007-7
Abstract: A consortium with autotrophic anaerobic ammonium oxidising (AAAO) activity was developed from municipal sludge, and its ability to remove high ammonium concentrations in a toxic wastewater such as coke ovens wastewater is presented here. The enriched AAAO consortium was acclimatised to a synthetic coke ovens wastewater to establish anaerobic ammonium oxidation (AAO) activity. Phenol was the main carbon component of the synthetic wastewater whereby it was added stepwise from 50+/-10 to 550+/-10 mg l(-1) into an anammox enrichment medium. Ammonium-N removal was initially impaired however, it gradually recovered. After 15 months of further selection and enrichment, the ammonium removal rate reached 62+/-2 mg NH(4)(+)-N l(-1) day(-1), i.e. 1.5 times the rate in the original AAAO reactor. The new consortium demonstrated higher ammonium and nitrite removal rates, even under phenol perturbation (up to 330+/-10 mg l(-1)). It is therefore concluded that the AAO activity in the consortium was resistant to high phenol and has potential for treating coke-ovens wastewater.
Science-based pathogen treatment requirements for direct potable reuse
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D3EW00362K
Marine nitrous oxide emissions: An unknown liability for the international water sector
Publisher: Elsevier BV
Date: 11-2013
Microbiology of ornithogenic soils from the windmill islands, budd coast, continental Antarctica: Microbial biomass distribution
Publisher: Elsevier BV
Date: 02-1993
Incorporating method recovery uncertainties in stochastic estimates of raw water protozoan concentrations for QMRA
Publisher: IWA Publishing
Date: 09-2007
DOI: 10.2166/WH.2007.142
Abstract: The impact of incorporating recovery data on protozoan concentration estimates was investigated for Cryptosporidium and Giardia using a large dataset (n=99) of [oo]cyst assay results with paired recovery estimates. Stochastic [oo]cyst concentration was estimated using three approaches: I – no availability/consideration of recovery, II – limited recovery data, where s le recovery was considered as an independent random variable, and III – every [oo]cyst assay result was adjusted for a concurrently derived recovery estimate. Critically, Approach I underestimated [oo]cyst concentrations by about 100% compared to Approaches II and III, which were similar. The impact of dataset size on statistical uncertainty about the concentration estimate for Approach II was investigated little improvement in parameter uncertainty was achieved beyond n=20. It is suggested that recovery data be incorporated into source water concentration estimates, especially when used to infer health risks to consumers, so as not to underestimate the risk. Where none is available, conservatively low recoveries should be assumed. When designing monitoring programmes, recovery data should be collected as a pair with [oo]cyst count data for an initial period at least, so that site-specific relationships between those parameters may be ascertained and incorporated into source water concentration estimates.
Comparative human health risk analysis of coastal community water and waste service options
Publisher: American Chemical Society (ACS)
Date: 23-07-2014
DOI: 10.1021/ES501262P
Abstract: As a pilot approach to describe adverse human health effects from alternative decentralized community water systems compared to conventional centralized services (business-as-usual [BAU]), selected chemical and microbial hazards were assessed using disability adjusted life years (DALYs) as the common metric. The alternatives included: (1) composting toilets with septic system, (2) urine- erting toilets with septic system, (3) low flush toilets with blackwater pressure sewer and on-site greywater collection and treatment for nonpotable reuse, and (4) alternative 3 with on-site rainwater treatment and use. Various pathogens (viral, bacterial, and protozoan) and chemicals (disinfection byproducts [DBPs]) were used as reference hazards. The exposure pathways for BAU included accidental ingestion of contaminated recreational water, ingestion of cross-connected sewage to drinking water, and shower exposures to DBPs. The alternative systems included ingestion of treated greywater from garden irrigation, toilet flushing, and crop consumption and ingestion of treated rainwater while showering. The pathways with the highest health impact included the ingestion of cross-connected drinking water and ingestion of recreational water contaminated by septic seepage. These were also among the most uncertain when characterizing input parameters, particularly the scale of the cross-connection event, and the removal of pathogens during groundwater transport of septic seepage. A comparison of the health burdens indicated potential health benefits by switching from BAU to decentralized water and wastewater systems.
Cost-effectiveness of nitrogen mitigation by alternative household wastewater management technologies
Publisher: Elsevier BV
Date: 03-2015
DOI: 10.1016/J.JENVMAN.2014.10.002
Abstract: Household wastewater, especially from conventional septic systems, is a major contributor to nitrogen pollution. Alternative household wastewater management technologies provide similar sewerage management services but their life cycle costs and nitrogen flow implications remain uncertain. This paper addresses two key questions: (1) what are the total costs, nitrogen mitigation potential, and cost-effectiveness of a range of conventional and alternative municipal wastewater treatment technologies, and (2) what uncertainties influence these outcomes and how can we improve our understanding of these technologies? We estimate a household nitrogen mass balance for various household wastewater treatment systems and combine this mass balance with life cycle cost assessment to calculate the cost-effectiveness of nitrogen mitigation, which we define as nitrogen removed from the local watershed. We apply our methods to Falmouth, MA, where failing septic systems have caused heightened eutrophication in local receiving water bodies. We find that flushing and dry (composting) urine- ersion toilets paired with conventional septic systems for greywater management demonstrate the lowest life cycle cost and highest cost-effectiveness (dollars per kilogram of nitrogen removed from the watershed). Composting toilets are also attractive options in some cases, particularly best-case nitrogen mitigation. Innovative/advanced septic systems designed for high-level nitrogen removal are cost-competitive options for newly constructed homes, except at their most expensive. A centralized wastewater treatment plant is the most expensive and least cost-effective option in all cases. Using a greywater recycling system with any treatment technology increases the cost without adding any nitrogen removal benefits. Sensitivity analysis shows that these results are robust considering a range of cases and uncertainties.
The Sixth International Water and Health Seminar, Cannes 2014
Publisher: Elsevier BV
Date: 11-2015
Water safety management during the initial phase of the Covid-19 pandemic: challenges, responses and guidance
Publisher: Informa UK Limited
Date: 21-01-2022
Genome sequencing reveals the environmental origin of enterococci and potential biomarkers for water quality monitoring
Publisher: American Chemical Society (ACS)
Date: 12-03-2014
DOI: 10.1021/ES4054835
Abstract: Enterococci are common members of the gut microbiome and their ease of culturing has facilitated worldwide use as indicators of fecal pollution of waters. However, enterococci were recently shown to persist in environmental habitats, often in the absence of fecal input, potentially confounding water quality assays. Toward resolving this issue and providing a more complete picture of natural enterococci ersity, 11 isolates of Enterococcus faecalis recovered from freshwater watersheds (environmental) were sequenced and compared to 59 available enteric genomes. Phenotypically and phylogenetically the environmental E. faecalis were indistinguishable from their enteric counterparts. However, distinct environmental- and enteric-associated gene signatures, encoding mostly accessory nutrient utilization pathways, were detected among the variable genes. Specifically, a nickel uptake operon was over-represented in environmental genomes, while genes for utilization of sugars thought to be abundant in the gut such as xylose were over-represented in enteric genomes. The distribution and phylogeny of these identified signatures suggest that ancestors of E. faecalis resided in extra-enteric habitats, challenging the prevailing commensal view of enterococci ecology. Thus, habitat-associated gene content changes faster than core genome phylogeny and may include biomarkers for reliably detecting fecal contaminants for improved microbial water quality monitoring.
Outer Limits of Flow Cytometry to Quantify Viruses in Water
Publisher: American Chemical Society (ACS)
Date: 08-03-2021
Assessing burden of disease as disability adjusted life years in life cycle assessment
Publisher: Elsevier BV
Date: 10-2015
DOI: 10.1016/J.SCITOTENV.2015.05.017
Abstract: Disability adjusted life years (DALYs) have been used to quantify endpoint indicators of the human burden of disease in life cycle assessment (LCA). The purpose of this paper was to examine the current use of DALYs in LCA, and also to consider whether DALYs as used in LCA have the potential to be compatible with DALYs as used in quantitative risk assessment (QRA) to facilitate direct comparison of the results of the two approaches. A literature review of current usage of DALYs in LCA was undertaken. Two prominent methods were identified: ReCiPe 2008 and LIME2. The methods and assumptions used in their calculations were then critically reviewed. The assumptions used for the derivation of characterization factors in DALYs were found to be considerably different between LCA methods. In many cases, transparency of these calculations and assumptions is lacking. Furthermore, global average DALY values are often used in these calculations, but may not be applicable for impact categories where the local factors play a significant role. The concept of DALYs seems beneficial since it enables direct comparison and aggregation of different health impacts. However, given the different assumptions used in each LCA method, it is important that LCA practitioners are aware of the differences and select the appropriate method for the focus of their study. When applying DALYs as a common metric between LCA and QRA, understanding the background information on how DALYs were derived is crucial to ensure the consistency of DALYs used in LCA and QRA for resulting DALYs to be comparable and to minimize any double counting of effects.
Molecular detection of Campylobacter spp. in California gull (Larus californicus) excreta
Publisher: American Society for Microbiology
Date: 15-07-2011
DOI: 10.1128/AEM.00018-11
Abstract: We examined the prevalence, quantity, and ersity of C ylobacter species in the excreta of 159 California gull ( Larus californicus ) s les using culture-, PCR-, and quantitative PCR (qPCR)-based detection assays. C ylobacter prevalence and abundance were relatively high in the gull excreta examined however, C. jejuni and C. lari were detected in fewer than 2% of the isolates and DNA extracts from the fecal s les that tested positive. Moreover, molecular and sequencing data indicated that most L. californicus c ylobacters were novel ( % 16S rRNA gene sequence identity to known C ylobacter species) and not closely related to species commonly associated with human illness. C ylobacter estimates were positively related with those of fecal indicators, including a gull fecal marker based on the Catellicoccus marimammalium 16S rRNA gene.
Editorial: Important news about this journal
Publisher: IWA Publishing
Date: 03-2021
DOI: 10.2166/WCC.2021.000
Enterobius vermicularis as a Novel Surrogate for the Presence of Helminth Ova in Tertiary Wastewater Treatment Plants
Publisher: American Society for Microbiology
Date: 06-2017
DOI: 10.1128/AEM.00547-17
Abstract: Significant effort has gone into assessing the fate and removal of viruses, bacteria, and protozoan parasites during wastewater treatment to provide data addressing potential health risks associated with reuse options. Comparatively less is known about the fate of parasitic worm species ova in these complex systems. It is largely assumed that these helminths settle, are removed with the sludge, and consequently represent a relatively low risk for wastewater reuse applications. However, helminths are a highly erse group of organisms that display a wide range of physical properties that complicate the application of a single treatment for helminth reduction during wastewater treatment. Moreover, their erse biological and physical properties make some ova highly resistant to both disinfection (i.e., with chlorine or UV treatment) and physical removal (settling) through the wastewater treatment train, indicating that there may be reason to broaden the scope of our investigations into whether parasitic worm eggs can be identified in treated wastewater. The ubiquitous human parasitic nematode Enterobius vermicularis (pinworm) produces small, buoyant ova. Utilizing a novel diagnostic quantitative PCR (qPCR), this study monitored E. vermicularis presence at two full-scale wastewater treatment plants over the course of 8 months and demonstrated incomplete physical removal of E. vermicularis ova through tertiary treatment, with removal efficiencies approximating only 0.5 and 1.6 log 10 at the two wastewater treatment plants based on qPCR. These findings demonstrate the need for more- erse surrogates of helminthic ova to fully assess treatment performance with respect to reclaimed wastewaters. IMPORTANCE Helminths, despite being a erse and environmentally resistant class of pathogens, are often underestimated and ignored when treatment performance at modern wastewater treatment plants is considered. A one-size-fits-all surrogate for removal of helminth ova may be inappropriate to adequately assess risk and ensure public safety when treated and partially treated wastewaters are encountered. This study argues for the use of human pinworm as a conservative indicator of the presence of helminth ova due to its small size, buoyancy, prevalence in humans, and environmental resistance.
Detection of Specific Microorganisms in Environmental Samples Using Flow Cytometry
Publisher: Elsevier
Date: 1994
Public health and water quality management in low-exposure stormwater schemes: A critical review of regulatory frameworks and path forward
Publisher: Elsevier BV
Date: 2017
Extracellular amoebal-vesicles: potential transmission vehicles for respiratory viruses
Publisher: Springer Science and Business Media LLC
Date: 17-03-2021
DOI: 10.1038/S41522-021-00201-Y
Abstract: Human respiratory syncytial virus (RSV) is a major cause of acute respiratory tract infections in children and immunocompromised adults worldwide. Here we report that amoebae-release respirable-sized vesicles containing high concentrations of infectious RSV that persisted for the duration of the experiment. Given the ubiquity of amoebae in moist environments, our results suggest that extracellular amoebal-vesicles could contribute to the environmental persistence of respiratory viruses, including potential resistance to disinfection processes and thereby offering novel pathways for viral dissemination and transmission.
Bacteriophages as indicators of faecal pollution and enteric virus removal
Publisher: Oxford University Press (OUP)
Date: 05-06-2017
DOI: 10.1111/LAM.12736
Building the case for water and resource recovery in Canada: practitioners' perspectives
Publisher: IWA Publishing
Date: 12-01-2021
DOI: 10.2166/WP.2021.206
Abstract: Water and resource recovery (WRR) involves the collection and treatment of rainwater, stormwater, and/or municipal wastewater to a fit-for-purpose standard. There is no national policy for WRR in Canada, and there are minimal WRR-specific provincial regulations given this lack of regulation, current projects are highly specific to the local context and approved in idually. We engaged people who work with water and wastewater services in the province of Alberta, Canada to discuss what WRR could look like in their context. During 3-h workshops, information on WRR was shared and participants engaged in discussions using a World Café process. Participants discussed the need for supportive regulations and government leadership, financial support, collaboration and knowledge sharing, education and communication, and accounting for risk and liability. Given that the participants are in iduals who would be impacted by the development of regulations for WRR, we discuss concepts to provide the guidance needed for the successful implementation of WRR. This research connected experts in water and wastewater and gave space for developing ideas that make sense to those most closely involved in delivering WRR systems.
Centralised versus decentralised sewage systems: a comparison of pathogen and nutrient loads released into Sydney's drinking water catchments
Publisher: IWA Publishing
Date: 12-2004
Abstract: Data collected from centralised and decentralised sewage treatment plants throughout Sydney's drinking water catchments was used to calculate the relative catchment loads of Cryptosporidium, enteric viruses, nitrogen and phosphorus for an initial screening assessment. Loads were assessed at median and 90 percentile values for expected and worst-cases scenarios. The expected scenario in the Sydney drinking water catchments is that decentralised systems (servicing 32,800 people) provide similar total loads to centralised systems (serving 70% of the catchment population) for total phosphorus (37,090 kg.y-1), Cryptosporidium (1011 oocysts.y-1) and enteric viruses (9.1 × 1013 y-1), but higher loads of total nitrogen (237,610 vs. 136,740 kg.y-1). Decentralised systems, however, were predicted to have higher loads in the worst-case scenario with 620,620 kg.y-1 TN, 82,040 kg.y-1 TP, 7.3 × 1013Cryptosporidium oocysts.y-1 and 9 × 1015 enteric viruses per year. Greater load variability was experienced with decentralised systems, which presumably reflects less reliability in their current operation and maintenance. Overall, catchment water quality is therefore not only affected by sewage disposal methods, but also failure issues. Decentralised system disposal to land may afford a degree of mitigation that can be enhanced, if the degree of failure is reduced.
Development of a process-based model to predict pathogen budgets for the Sydney drinking water catchment
Publisher: IWA Publishing
Date: 06-2007
DOI: 10.2166/WH.2007.013B
Abstract: In drinking water catchments, reduction of pathogen loads delivered to reservoirs is an important priority for the management of raw source water quality. To assist with the evaluation of management options, a process-based mathematical model (pathogen catchment budgets - PCB) is developed to predict Cryptosporidium, Giardia and E. coli loads generated within and exported from drinking water catchments. The model quantifies the key processes affecting the generation and transport of microorganisms from humans and animals using land use and flow data, and catchment specific information including point sources such as sewage treatment plants and on-site systems. The resultant pathogen catchment budgets (PCB) can be used to prioritize the implementation of control measures for the reduction of pathogen risks to drinking water. The model is applied in the Wingecarribee catchment and used to rank those sub-catchments that would contribute the highest pathogen loads in dry weather, and in intermediate and large wet weather events. A sensitivity analysis of the model identifies that pathogen excretion rates from animals and humans, and manure mobilization rates are significant factors determining the output of the model and thus warrant further investigation.
Rapid identification of Aeromonas species using 16S rDNA targeted oligonucleotide primers: a molecular approach based on screening of environmental isolates
Publisher: Wiley
Date: 12-1994
DOI: 10.1111/J.1365-2672.1994.TB02825.X
Abstract: Published 16S rDNA sequencing data for Aeromonas species were analysed and the validity of signature sequences derived from our investigations of these sequences was examined by sequencing the corresponding 16S rDNA regions of 67 environmental isolates from sewage effluents and receiving waters around Sydney and one clinical isolate, all previously classified as Aeromonas species. Species-specific probes for Aer. hydrophila and Aer. veronii were designed and tested in PCR assays and clearly discriminated these species from the other Aeromonas isolates as identified by 16S rDNA sequences.
Biotic Interactions and Sunlight Affect Persistence of Fecal Indicator Bacteria and Microbial Source Tracking Genetic Markers in the Upper Mississippi River
Publisher: American Society for Microbiology
Date: 07-2014
DOI: 10.1128/AEM.00388-14
Abstract: The sanitary quality of recreational waters that may be impacted by sewage is assessed by enumerating fecal indicator bacteria (FIB) ( Escherichia coli and enterococci) these organisms are found in the gastrointestinal tracts of humans and many other animals, and hence their presence provides no information about the pollution source. Microbial source tracking (MST) methods can discriminate between different pollution sources, providing critical information to water quality managers, but relatively little is known about factors influencing the decay of FIB and MST genetic markers following release into aquatic environments. An in situ mesocosm was deployed at a temperate recreational beach in the Mississippi River to evaluate the effects of ambient sunlight and biotic interactions (predation, competition, and viral lysis) on the decay of culture-based FIB, as well as molecularly based FIB (Entero1a and GenBac3) and human-associated MST genetic markers (HF183 and HumM2) measured by quantitative real-time PCR (qPCR). In general, culturable FIB decayed the fastest, while molecularly based FIB and human-associated genetic markers decayed more slowly. There was a strong correlation between the decay of molecularly based FIB and that of human-associated genetic markers ( r 2 , 0.96 to 0.98 P 0.0001) but not between culturable FIB and any qPCR measurement. Overall, exposure to ambient sunlight may be an important factor in the early-stage decay dynamics but generally was not after continued exposure (i.e., after 120 h), when biotic interactions tended to be the only/major influential determinant of persistence.
Spiked Virus Level Needed To Correctly Assess Enteric Virus Recovery in Water Matrices
Publisher: American Society for Microbiology
Date: 15-06-2019
DOI: 10.1128/AEM.00111-19
Abstract: The performance of procedures for pathogen log reduction is at the heart of new risk-based guidance/regulation globally, yet the methods for undertaking assessments of pathogen recovery are not standardized despite their fundamental impacts on assessing log reductions. Here we describe the level of spiking agent(s) that is necessary to correctly assess spiked pathogen/surrogate recovery with whatever method is deployed. The significance of our research lies in identifying the importance of the amount of spiking agents for reducing uncertainty in recovery estimates, which will allow the development of a recommendation for spiking experiments, proactively applying this understanding.
First evidence of free-living Naegleria species in recreational lakes of Alberta, Canada
Publisher: IWA Publishing
Date: 17-02-2023
DOI: 10.2166/WH.2023.325
Abstract: Rising temperatures are increasing environmental habitats for thermotolerant pathogens, such as the so-called ‘brain-eating amoeba’, Naegleria fowleri. To the best of our knowledge, however, Naegleria species have not been reported in environmental water sources in Canada. We surveyed popular recreational lakes in Alberta, Canada during the summer bathing period to determine the presence or absence of Naegleria species. While N. fowleri was not isolated in this study, we identified other thermotolerant species, including Naegleria pagei, Naegleria gruberi, Naegleria jejuensis and Naegleria fultoni using culture-based methods, hence indicating the potential conditions to support N. fowleri. Ongoing monitoring and examination of water for pathogenic amoebae is recommended in order to assist in the public health management of water sources.
Colloid chemistry pitfall for flow cytometric enumeration of viruses in water
Publisher: Elsevier BV
Date: 02-2019
Risk analysis of drinking water microbial contamination versus disinfection by-products (DBPs)
Publisher: Elsevier BV
Date: 05-2004
Fate and transport of pathogens in lakes and reservoirs
Publisher: Elsevier BV
Date: 07-2004
Artifical groundwater treatment: biofilm activity and organic carbon removal performance
Publisher: Elsevier BV
Date: 02-2004
Response of Simulated Drinking Water Biofilm Mechanical and Structural Properties to Long-Term Disinfectant Exposure
Publisher: American Chemical Society (ACS)
Date: 26-01-2016
Microbial contamination of drinking water and disease outcomes in developing regions
Publisher: Elsevier BV
Date: 05-2004
Arctic antibiotic resistance gene contamination, a result of anthropogenic activities and natural origin
Publisher: Elsevier BV
Date: 04-2018
DOI: 10.1016/J.SCITOTENV.2017.10.110
Abstract: The increasing global prevalence of antibiotic resistance genes (ARGs) in the environment is attributed to anthropogenic activities, particularly the misuse of antimicrobial drugs in human care and animal production. In the present study, we first examined Arctic/sub-Arctic (polar) sediments for the abundance and ersity of 30 ARGs against sulfonamide, tetracycline, aminoglycoside, quinolone, macrolide, and β-lactam antibiotics. Polar sediment ARGs were detected by qPCR at relatively low levels (10
Microbiology of ornithogenic soils from the windmill islands, budd coast, continental Antarctica: Some observations on methods for measuring soil biomass in ornithogenic soils
Publisher: Elsevier BV
Date: 02-1993
Pseudomonas aeruginosadose response and bathing water infection
Publisher: Cambridge University Press (CUP)
Date: 08-11-2013
DOI: 10.1017/S0950268813002690
Abstract: Pseudomonas aeruginosa is the opportunistic pathogen mostly implicated in folliculitis and acute otitis externa in pools and hot tubs. Nevertheless, infection risks remain poorly quantified. This paper reviews disease aetiologies and bacterial skin colonization science to advance dose-response theory development. Three model forms are identified for predicting disease likelihood from pathogen density. Two are based on Furumoto & Mickey's exponential ‘single-hit’ model and predict infection likelihood and severity (lesions/m 2 ), respectively. ‘Third-generation’, mechanistic, dose-response algorithm development is additionally scoped. The proposed formulation integrates dispersion, epidermal interaction, and follicle invasion. The review also details uncertainties needing consideration which pertain to water quality, outbreaks, exposure time, infection sites, biofilms, cerumen, environmental factors (e.g. skin saturation, hydrodynamics), and whether P. aeruginosa is endogenous or exogenous. The review's findings are used to propose a conceptual infection model and identify research priorities including pool dose-response modelling, epidermis ecology and infection likelihood-based hygiene management.
Adequacy of in situ glass slides and direct sand extractions to assess the microbiota within sand columns used for drinking water treatment
Publisher: Canadian Science Publishing
Date: 07-2001
DOI: 10.1139/W01-052
Abstract: Historically, Cholodny-Rossi buried glass slide techniques have been used to study the microbiota of subsurface environments, yet the bias of such a technique has not been compared against direct sand extraction using modern in situ probing. Over a period of 34 wk, four separate 4-m-deep sand columns receiving raw lake water were examined to compare direct extraction of sand filter biofilm material against in situ glass slide biofilms. Significantly different DAPI direct counts and fluorescent in situ hybridization signals for major phylogenetic groups were observed. Not only were lower proportions (P 0.001) of EUB338-probed DAPI cells observed on in situ glass slides, but also fewer γ-Proteobacteria (12%21%) and more α-Proteobacteria (16%33%) when compared to direct sand extracts. Hence, investigators of the microbial ecology of even simple sand biofilms must consider the inherent biases from "accepted" methods and seek further independent methods to identify those which may be most accurate.Key words: sand filter, biofilms, in situ hybridization, groundwater recharge.
Whole-genome sequencing of four Campylobacter strains isolated from gull excreta collected from Hobie Beach (Oxnard, CA, USA)
Publisher: American Society for Microbiology
Date: 08-08-2019
DOI: 10.1128/MRA.00560-19
Abstract: C ylobacter spp. are commensal organisms in avian species and are one of the leading causes of bacterial foodborne human diarrheal disease worldwide. We report the draft genome sequences of C ylobacter volucris , C. lari , and C. jejuni strains isolated from California gull ( Larus californicus ) excreta collected from a California beach.
Viral persistence in source-separated human urine
Publisher: Elsevier BV
Date: 09-2002
Quantifying the impact of runoff events on microbiological contaminant concentrations entering surface drinking source waters
Publisher: IWA Publishing
Date: 12-2005
DOI: 10.2166/WH.2005.052
Abstract: Concentrations of microbiological contaminants in streams increase during rainfall-induced higher flow ‘event’ periods as compared to ‘baseflow’ conditions. If the stream feeds a drinking water reservoir, such periods of heightened pathogen loads may pose a challenge to the water treatment plant and subsequently a health concern to water consumers downstream. In order to manage this risk, it is desirable to first quantify the differences in surface water quality between baseflow and event conditions. The Event Mean Concentration (EMC) is a flow-weighted average concentration of a contaminant over the duration of a single event, proposed here as a standard parameter for quantifying the net effect of events on microbial water quality. Application of the EMC concept was assessed using flow and quality data for several events from an urbanised catchment. Expected mean EMCs were significantly larger than expected mean baseflow concentrations (p-value≤0.012) for three microbial agents - Escherichia coli (13,000 [n = 7] v. 610 [n = 16] mpn/100 ml), Cryptosporidium (234 [n = 6] v. 51 [n = 16] oocysts/10 litres) and C ylobacter (48 [n = 5] v. 2.1 [n = 16] mpn/100 ml). These parameter estimates were complemented by estimating data variability and uncertainty in the form of second-order random variables. As such the results are in a format appropriate for potential use as components in probabilistic risk assessments evaluating the effect runoff events have on drinking water quality.
Anammox reactor optimization for the treatment of ammonium rich digestate lagoon supernatant - Step feeding mitigates nitrite inhibition
Publisher: Elsevier BV
Date: 09-2019
Effluent quality from 200 on-site sewage systems: design values for guidelines
Publisher: IWA Publishing
Date: 05-2005
Abstract: The quality of effluent from an on-site sewage treatment system is a critical factor in designing the disposal area and, hence, ensuring the sustained performance of the system. Contaminant concentrations in effluent are typically specified in regulatory guidelines or standards however, the accuracy of these guideline values are brought into question due to the poor performance of septic tanks and the high failure rates of disposal systems reported here and elsewhere. Results from studies of septic tank effluent quality indicated that the effluent is of poorer quality than currently suggested by guidelines. Aerated wastewater treatment systems were found to perform to accreditation guidelines however, insufficient nutrient data is presently available to assess nutrient loads. It is proposed that the 80th percentile of system performance be adopted as the design value for sizing effluent disposal areas to minimise failure associated with overloading. For septic tanks this equates to 660 mg L−1 SS, 330 mg L−1 BOD, 250 mg L−1 TN and 36 mg L−1 TP.
The fate of Helicobacter pylori phagocytized by Acanthamoeba polyphaga demonstrated by fluorescent in situ hybridization and quantitative polymerization chain reaction tests
Publisher: Springer Science and Business Media LLC
Date: 23-09-2012
DOI: 10.1007/S00284-012-0232-2
Abstract: Helicobacter pylori able to express green fluorescent protein, as well as an ATCC strain, and a clinical isolate of this pathogen were evaluated for their ability to survive predation by Acanthamoeba polyphaga. Ingestion was evaluated by microscopic observation of the GFP-H. pylori and BacLight™-stained cells. Following phagocytosis, the fate of cells was assessed by fluorescent in situ hybridization with an oligonucleotide targeting H. pylori 16S rRNA and by quantitative-polymerase chain reaction (qPCR) tests with primers to 16S rDNA. Fluorescent in situ hybridization tests were inconclusive with only a small percentage of amoebae apparently containing active intracellular H. pylori. Furthermore, no increase in bacterial cells was detected by qPCR. Additional research is required to elucidate the mechanisms by which amoebae phagocytize this important bacterial pathogen.
Differential growth of Legionella pneumophila strains within a range of amoebae at various temperatures associated with in-premise plumbing
Publisher: Oxford University Press (OUP)
Date: 15-06-2011
Free-Living Amoebae Supporting Intracellular Growth May Produce Vesicle-Bound Respirable Doses of Legionella Within Drinking Water Systems
Publisher: Springer Science and Business Media LLC
Date: 25-09-2018
QMRA (quantitative microbial risk assessment) and HACCP (hazard analysis and critical points) for management of pathogens in wastewater and sewage sludge treatment and reuse
Publisher: IWA Publishing
Date: 07-2004
Abstract: Hazard Analysis and Critical Control Points (HACCP) was applied for identifying and controlling exposure to pathogenic microorganisms encountered during normal sludge and wastewater handling at a 12,500 m3/d treatment plant utilising tertiary wastewater treatment and mesophilic sludge digestion. The hazardous scenarios considered were human exposure during treatment, handling, soil application and crop consumption, and exposure via water at the wetland-area and recreational swimming. A quantitative microbial risk assessment (QMRA), including rotavirus, adenovirus, haemorrhagic E. coli, Salmonella, Giardia and Cryptosporidium, was performed in order to prioritise pathogen hazards for control purposes. Human exposures were treated as in idual risks but also related to the endemic situation in the general population. The highest in idual health risk from a single exposure was via aerosols for workers at the belt press for sludge dewatering (virus infection risk = 1). The largest impact on the community would arise if children ingested sludge at the unprotected storage site, although in the worst-case situation the largest number of infections would arise through vegetables fertilised with sludge and eaten raw (not allowed in Sweden). Acceptable risk for various hazardous scenarios, treatment and/or reuse strategies could be tested in the model.
Twenty five years of beach monitoring in Hong Kong: A re-examination of the beach water quality classification scheme from a comparative and global perspective
Publisher: Elsevier BV
Date: 06-2018
DOI: 10.1016/J.MARPOLBUL.2018.05.002
Abstract: Hong Kong's beach water quality classification scheme, used effectively for >25 years in protecting public health, was first established in local epidemiology studies during the late 1980s where Escherichia coli (E. coli) was identified as the most suitable faecal indicator bacteria. To review and further substantiate the scheme's robustness, a performance check was carried out to classify water quality of 37 major local beaches in Hong Kong during four bathing seasons (March-October) from 2010 to 2013. Given the enterococci and E. coli data collected, beach classification by the local scheme was found to be in line with the prominent international benchmarks recommended by the World Health Organization and the European Union. Local bacteriological studies over the last 15 years further confirmed that E. coli is the more suitable faecal indicator bacteria than enterococci in the local context.
Legionellae in engineered systems and use of quantitative microbial risk assessment to predict exposure
Publisher: Elsevier BV
Date: 03-2012
DOI: 10.1016/J.WATRES.2011.12.022
Abstract: While it is well-established that Legionella are able to colonize engineered water systems, the number of interacting factors contributing to their occurrence, proliferation, and persistence are unclear. This review summarizes current methods used to detect and quantify legionellae as well as the current knowledge of engineered water system characteristics that both favour and promote legionellae growth. Furthermore, the use of quantitative microbial risk assessment (QMRA) models to predict potentially critical human exposures to legionellae are also discussed. Understanding the conditions favouring Legionella occurrence in engineered systems and their overall ecology (growth in these systems/biofilms, biotic interactions and release) will aid in developing new treatment technologies and/or systems that minimize or eliminate human exposure to potentially pathogenic legionellae.
A new approach to aid urban water management decision making using trade-off sacrifice modelled byfuzzy logic
Publisher: IWA Publishing
Date: 10-2007
DOI: 10.2166/WST.2007.597
Abstract: An approach to aid decision making for urban water management is presented that is based on the concept of trade-off sacrifice level in pairwise comparisons between criteria, modelled using fuzzy logic. This approach is illustrated by a case study – selection of alternative water supplies for a Sydney household. Four key decision making criteria covering health, economic, environment and technical aspects are selected: annual probability of infection, life cycle energy use, life cycle cost and reliability. The decision making problem is to select between cases with different volume and application of recycled greywater and rainwater in light of the four criteria. Decision maker's preference is expressed by five levels of trade-off sacrifice between pairs of criteria. The decision makers can assign their preferences for sacrifice level by linguistic assessment and the output trade-off weight (TOW). Measures of decision makers' perceived trade-off level are modelled by a rule-based fuzzy logic control system. The final analysis shows the performance for each sacrifice class for each case, to aid overall decision making with stakeholders.
Development and Evaluation of a Quantitative PCR Assay Targeting Sandhill Crane (Grus canadensis) Fecal Pollution
Publisher: American Society for Microbiology
Date: 15-06-2012
DOI: 10.1128/AEM.07923-11
Abstract: While the microbial water quality in the Platte River is seasonally impacted by excreta from migrating cranes, there are no methods available to study crane fecal contamination. Here we characterized microbial populations in crane feces using phylogenetic analysis of 16S rRNA gene fecal clone libraries. Using these sequences, a novel crane quantitative PCR (Crane1) assay was developed, and its applicability as a microbial source tracking (MST) assay was evaluated by determining its host specificity and detection ability in environmental waters. Bacteria from crane excreta were dominated by bacilli and proteobacteria, with a notable paucity of sequences homologous to Bacteroidetes and Clostridia . The Crane1 marker targeted a dominant clade of unclassified Lactobacillales sequences closely related to Catellicoccus marimammalium . The host distribution of the Crane1 marker was relatively high, being positive for 69% (66/96) of the crane excreta s les tested. The assay also showed high host specificity, with 95% of the nontarget fecal s les (i.e., n = 553 20 different free-range hosts) being negative. Of the presumed crane-impacted water s les ( n = 16), 88% were positive for the Crane1 assay, whereas none of the water s les not impacted by cranes were positive ( n = 165). Bayesian statistical models of the Crane1 MST marker demonstrated high confidence in detecting true-positive signals and a low probability of false-negative signals from environmental water s les. Altogether, these data suggest that the newly developed marker could be used in environmental monitoring studies to study crane fecal pollution dynamics.
An in-premise model for Legionella exposure during showering events
Publisher: Elsevier BV
Date: 11-2011
DOI: 10.1016/J.WATRES.2011.08.031
Abstract: An exposure model was constructed to predict the critical Legionella densities in an engineered water system that result in infection from inhalation of aerosols containing the pathogen while showering. The model predicted the Legionella densities in the shower air, water and in-premise plumbing biofilm that might result in a deposited dose of Legionella in the alveolar region of the lungs associated with infection for a routine showering event. Processes modeled included the detachment of biofilm-associated Legionella from the in-premise plumbing biofilm during a showering event, the partitioning of the pathogen from the shower water to the air, and the inhalation and deposition of particles in the lungs. The range of predicted critical Legionella densities in the air and water was compared to the available literature. The predictions were generally within the limited set of observations for air and water, with the exception of Legionella density within in-premise plumbing biofilms, for which there remains a lack of observations for comparison. Sensitivity analysis of the predicted results to possible changes in the uncertain input parameters identified the target deposited dose associated with infections, the pathogen air-water partitioning coefficient, and the quantity of detached biofilm from in-premise pluming surfaces as important parameters for additional data collection. In addition, the critical density of free-living protozoan hosts in the biofilm required to propagate the infectious Legionella was estimated. Together, this evidence can help to identify critical conditions that might lead to infection derived from pathogens within the biofilms of any plumbing system from which humans may be exposed to aerosols.
Soil inactivation of DNA viruses in septic seepage
Publisher: Oxford University Press (OUP)
Date: 02-2006
DOI: 10.1111/J.1365-2672.2005.02777.X
Abstract: To generate field-relevant inactivation data for incorporation into models to predict the likelihood of viral contamination of surface waters by septic seepage. Inactivation rates were determined for PRD1 bacteriophage and Adenovirus 2 in two catchment soils under a range of temperature, moisture and biotic status regimes. Inactivation rates presented for both viruses were significantly different at different temperatures and in different soil types (alpha = 0.05). Soil moisture generally did not significantly affect virus inactivation rate. Biotic status significantly affected inactivation rates of PRD1 in the loam soil but not the clay-loam soil. Adenovirus 2 was inactivated more rapidly in the loam soil than PRD1 bacteriophage. Virus inactivation rates incorporated into models should be appropriate for the climate/catchment in question with particular regard to soil type and temperature. Given that PRD1 is similar in size to adenoviruses, yet more conservative with regard to inactivation in soil, it may be a useful surrogate in studies of Adenovirus fate and transport. A better understanding of the factors that govern virus fate and transport in catchments would facilitate the design of barrier measures to prevent viral contamination of surface waters by septic seepage.
Role of Biofilm Roughness and Hydrodynamic Conditions in Legionella pneumophila Adhesion to and Detachment from Simulated Drinking Water Biofilms
Publisher: American Chemical Society (ACS)
Date: 11-03-2015
DOI: 10.1021/ES505842V
Enteric pathogen reduction targets for onsite non-potable water systems: A critical evaluation
Publisher: Elsevier BV
Date: 04-2023
A risk model for enteric virus accumulation and release from recycled water distribution pipe biofilms
Publisher: IWA Publishing
Date: 06-2003
DOI: 10.2166/WS.2003.0013
Abstract: Screening-level quantitative microbial risk assessments (QMRA) undertaken to assess health risks associated with the reticulation of recycled water have identified distribution pipe biofilms and their ability to accumulate enteric and opportunistic pathogens as potential sources of public health concern. A simplistic model to assess human health risks associated with enteric virions (extracellular viruses) present in recycled water for domestic use was therefore developed. Recycled water biofilms formed on glass and stainless steel coupons in a laboratory-scale distribution system were challenged with model enteric virions (B40-8, MS-2 and FX174 bacteriophages). Approximately 1% of bacteriophages present in the adjacent bulk water was incorporated into 3 month-old biofilms and a persistent sub-population (0.01%) of the model enteric virions remained infectious in biofilms throughout an experimental period of 30 days. Significant potential for virions to accumulate within biofilms was therefore demonstrated, and indeed biofilm uptake could mask treatment failures assessed through analysis of the bulk water (infectious virions would not be detected after 1.5 km even if 10.L-1 virions present in treated effluent). Subsequent sloughing of biofilm into the bulk water phase could therefore release infective virions within mobilized aggregates of biofilm and infect susceptible consumers. During normal operating conditions (one virion in 100 L of water) sufficient virions may accumulate within distribution pipe biofilms that a 50% sloughing event could present a Pi (annual) of 1.9 × 10-4 for the consumption of 1 mL of water, exceeding the US-EPA benchmark of 10-4.
Including pathogen risk in life cycle assessment: the effect of modelling choices in the context of sewage sludge management
Publisher: Springer Science and Business Media LLC
Date: 09-11-2015
Human Mitochondrial DNA and Endogenous Bacterial Surrogates for Risk Assessment of Graywater Reuse
Publisher: American Chemical Society (ACS)
Date: 07-2014
DOI: 10.1021/ES501659R
Abstract: Previous graywater risk assessment studies have focused on fecal contamination, yet the low density of fecal indicators may not provide the most useful approach to assess pathogen removal during graywater treatment. In this study, we employed high throughput bacterial sequencing and qPCR to elucidate potential microbial surrogates in wastewater sourced from an industrial laundry. In addition, we explored human mitochondrial DNA (HmtDNA) as a new, potentially more reliable molecular marker, because it can be unambiguously sourced, has a high copy number per cell, and is persistent when released from cells with no self-replication in graywater. Pyrosequencing and qPCR revealed that laundry water microbiota was dominated by the skin-associated bacteria Staphylococcus, Corynebacterium, and Propionibacterium (6.5, 5.7, 5.4 log10 copies/100 mL, respectively). While HmtDNA was less abundant (2.8 log10 copies/100 mL), it showed a strong positive correlation with the opportunistic pathogen Staphylococcus aureus (r=0.54, P=3.2×10(-4)) and closely followed a first-order exponential decay model (R2=0.98), remaining detectable in stored laundry graywater for up to 6 days at 20 °C. Based on abundance and persistence, we propose HmtDNA and total Staphylococcus as future laundry graywater treatment surrogates to potentially assess a wide dynamic range of pathogen removal.
Assessment of human virus removal during municipal wastewater treatment in Edmonton, Canada
Publisher: Oxford University Press (OUP)
Date: 22-11-2015
DOI: 10.1111/JAM.12971
Abstract: To assess the removal of viruses through the multiple steps of wastewater treatment in a full-scale municipal wastewater treatment plant in Alberta, Canada. S les were collected after each of the five treatment steps for a period of 16 months. The amount of viruses and their infectivity were analysed using real-time quantitative PCR (qPCR) and integrated viral cell culture (ICC), respectively. Bacterial indicator Escherichia coli was also tested using membrane filtration. Seven viruses including Norovirus (NoV), Rotavirus (RV), Sapovirus (SaV), Astrovirus (AsV), Adenovirus (AdV), Enterovirus (EV) and JC virus (JCV) were detected in 16 primary effluents in which infectious viruses were present. Different treatment steps showed various efficiencies in virus removal, with membrane ultrafiltration as the most effective at 4·6-7·0 log reduction. We observed high prevalence of viruses in raw wastewater and different viral reduction after various treatment steps. The discharge of treated wastewater with infectious viruses represents potential risks to human, animal and environmental health. This study provides a comprehensive assessment of the removal of NoV, RV, SaV, AsV, AdV, EV, JCV and Reovirus from wastewater by current procedures of municipal wastewater treatment and discusses the applicability of various viruses as viral indicators for water quality.
Assessing Pathogen Risk to Swimmers at Non-Sewage Impacted Recreational Beaches
Publisher: American Chemical Society (ACS)
Date: 04-03-2010
DOI: 10.1021/ES903523Q
Abstract: The risk of gastrointestinal illness to swimmers from fresh sewage and non-sewage fecal sources at recreational beaches was predicted using quantitative microbial risk assessment (QMRA). The QMRA estimated the probability of illness for accidental ingestion of recreational water with a specific concentration of fecal indicator bacteria, here the geometric mean enterococci limit of 35 cfu 100 mL(-1), from either a mixture of sources or an in idual source. Using seagulls as an ex le non-sewage fecal source, the predicted median probability of illness was less than the illness benchmark of 0.01. When the fecal source was changed to poorly treated sewage, a relativity small difference between the median probability of illness and the illness benchmark was predicted. For waters impacted by a mixture of seagull and sewage waste, the dominant source of fecal indicator was not always the predicted dominant source of risk.
Do Free-Living Amoebae in Treated Drinking Water Systems Present an Emerging Health Risk?
Publisher: American Chemical Society (ACS)
Date: 31-12-2011
DOI: 10.1021/ES102876Y
Abstract: There is an expanding body of evidence that free-living amoebae (FLA) increase both the numbers and virulence of water-based, human-pathogenic, amoeba-resisting microorganisms (ARM). Legionella spp., Mycobacterium spp., and other opportunistic human pathogens are known to be both ARM and also the etiologic agents of potentially fatal human lung infections. However, comparatively little is known about the FLA that may facilitate ARM growth in drinking water. This review examines the available literature on FLA in treated drinking water systems in total 26 studies from 18 different countries. FLA were reported to breakthrough the water treatment barrier and enter distribution systems, in addition to the expected post-treatment system ingress. Once in the distribution system there is evidence of FLA colonization and regrowth especially in reservoirs and in-premise plumbing storage tanks. At the point of use the average FLA detection rate was 45% but highly variable (n = 16, σ = 31) due to both differences in both assay methods and the type of water systems examined. This review reveals that FLA are consistently detected in treated drinking water systems around the world and present a yet unquantified emerging health risk. However, more research is urgently required before accurate risks assessments can be undertaken to assess the impacts on human health, in households and institutions, due to exposure to FLA facilitated pathogenic ARM.
Evaluation of various Campylobacter-specific quantitative PCR (qPCR) assays for detection and enumeration of Campylobacteraceae in irrigation water and wastewater via a miniaturized most-probable-number-qPCR assay
Publisher: American Society for Microbiology
Date: 08-2016
DOI: 10.1128/AEM.00077-16
Abstract: C ylobacter spp. are the leading cause of bacterial gastroenteritis worldwide, and water is increasingly seen as a risk factor in transmission. Here we describe a most-probable-number (MPN)–quantitative PCR (qPCR) assay in which water s les are centrifuged and aliquoted into microtiter plates and the bacteria are enumerated by qPCR. We observed that commonly used C ylobacter molecular assays produced vastly different detection rates. In irrigation water s les, detection rates varied depending upon the PCR assay and culture method used, as follows: 0% by the de Boer Lv1-16S qPCR assay, 2.5% by the Van Dyke 16S and Jensen glyA qPCR assays, and 75% by the Linton 16S endpoint PCR when cultured at 37°C. Primer robe specificity was the major confounder, with Arcobacter spp. routinely yielding false-positive results. The primers and PCR conditions described by Van Dyke et al. (M. I. Van Dyke, V. K. Morton, N. L. McLellan, and P. M. Huck, J Appl Microbiol 109:1053–1066, 2010, 0.1111/j.1365-2672.2010.04730.x ) proved to be the most sensitive and specific for C ylobacter detection in water. C ylobacter occurrence in irrigation water was found to be very low ( MPN/300 ml) when this C ylobacter -specific qPCR was used, with the most commonly detected species being C. jejuni , C. coli , and C. lari . C ylobacters in raw sewage were present at ∼10 2 /100 ml, with incubation at 42°C required for reducing microbial growth competition from arcobacters. Overall, when C ylobacter prevalence and/or concentration in water is reported using molecular methods, considerable validation is recommended when adapting methods largely developed for clinical applications. Furthermore, combining MPN methods with molecular biology-based detection algorithms allows for the detection and quantification of C ylobacter spp. in environmental s les and is potentially suited to quantitative microbial risk assessment for improved public health disease prevention related to food and water exposures. IMPORTANCE The results of this study demonstrate the importance of assay validation upon data interpretation of environmental monitoring for C ylobacter when using molecular biology-based assays. Previous studies describing C ylobacter prevalence in Canada utilized primers that we have determined to be nonspecific due to their cross- lification of Arcobacter spp. As such, C ylobacter prevalence may have been vastly overestimated in other studies. Additionally, the development of a quantitative assay described in this study will allow accurate determination of C ylobacter concentrations in environmental water s les, allowing more informed decisions to be made about water usage based on quantitative microbial risk assessment.
PhosPhAt: the Arabidopsis thaliana phosphorylation site database. An update
Publisher: Oxford University Press (OUP)
Date: 30-10-2009
DOI: 10.1093/NAR/GKP810
Derivation of numerical values for the World Health Organization guidelines for recreational waters
Publisher: Elsevier BV
Date: 03-2004
Simulation of enteric pathogen concentrations in locally-collected greywater and wastewater for microbial risk assessments
Publisher: Elsevier BV
Date: 04-2017
SARS-CoV-2 surrogate (Phi6) environmental persistence within free-living amoebae
Publisher: IWA Publishing
Date: 24-09-2022
DOI: 10.2166/WH.2021.167
Abstract: The reported persistence of SARS-CoV-2 virions in aquatic environments highlights the need to better understand potential mechanisms that may prolong its dissemination. We evaluated the possibility that amoebae might serve as transport hosts by studying the interaction of the enveloped bacteriophage Phi6, as a potential surrogated along with one of the most common amoebae in engineered aquatic environments, Vermamoeba vermiformis. Using microscopy, imaging flow cytometry and bacteriophage cell culture, our results imply that the SARS-CoV-2 surrogate triggers amoebic mitochondria and induced apoptosis to promote viral persistence in trophozoites. Furthermore, virus-infected amoebae were still infectious after 2 months within FLA cysts. These results suggest that amoebae could contribute to the environmental persistence of SARS-CoV-2, including disinfection processes. In addition, amoebae could be a successful model system for understanding respiratory virus-eukaryotic biology at the cellular and molecular levels.
New perspectives on microbial community distortion after whole-genome amplification.
Publisher: Public Library of Science (PLoS)
Date: 26-05-2015
Life Cycle Assessment of Community-Based Sewer Mining: Integrated Heat Recovery and Fit-For-Purpose Water Reuse
Publisher: MDPI AG
Date: 14-05-2020
DOI: 10.3390/ENVIRONMENTS7050036
Abstract: Municipal sewage contains significant embedded resources in the form of chemical and thermal energy. Recent developments in sustainable technology have pushed for the integration of resource recovery from household wastewater to achieve net zero energy consumption and carbon-neutral communities. Sewage heat recovery and fit-for-purpose water reuse are options to optimize the resource recovery potential of municipal wastewater. This study presents a comparative life cycle assessment (LCA) focused on global warming potential (GWP), eutrophication potential (EUP), and human health carcinogenic potential (HHCP) of an integrated sewage heat recovery and water reuse system for a hypothetical community of 30,000 people. Conventional space and water heating components generally demonstrated the highest GWP contribution between the different system components evaluated. Sewage-heat-recovery-based district heating offered better environmental performance overall. Lower impact contributions were demonstrated by scenarios with a membrane bioreactor (MBR) and chlorination prior to water reuse applications compared to scenarios that use more traditional water and wastewater treatment technologies and discharge. The LCA findings show that integrating MBR wastewater treatment and water reuse into a district heating schema could provide additional environmental savings at a community scale.
Simple model of attachment and detachment of pathogens in water distribution system biofilms
Publisher: American Society of Civil Engineers
Date: 12-05-2009
DOI: 10.1061/41036(342)15
Using quantitative microbial risk assessment and life cycle assessment to assess management options in urban water and sanitation infrastructures: Opportunities and unresolved issues
Publisher: Elsevier BV
Date: 04-2017
Capsid Integrity qPCR—An Azo-Dye Based and Culture-Independent Approach to Estimate Adenovirus Infectivity after Disinfection and in the Aquatic Environment
Publisher: MDPI AG
Date: 08-06-2019
DOI: 10.3390/W11061196
Abstract: Recreational, reclaimed and drinking source waters worldwide are under increasing anthropogenic pressure, and often contain waterborne enteric bacterial, protozoan, and viral pathogens originating from non-point source fecal contamination. Recently, the capsid integrity (ci)-qPCR, utilizing the azo-dyes propidium monoazide (PMA) or ethidium monoazide (EMA), has been shown to reduce false-positive signals under laboratory conditions as well as in food safety applications, thus improving the qPCR estimation of virions of public health significance. The compatibility of two widely used human adenovirus (HAdV) qPCR protocols was evaluated with the addition of a PMA/EMA pretreatment using a range of spiked and environmental s les. Stock suspensions of HAdV were inactivated using heat, UV, and chlorine before being quantified by cell culture, qPCR, and ci-qPCR. Apparent inactivation of virions was detected for heat and chlorine treated HAdV while there was no significant difference between ci-qPCR and qPCR protocols after disinfection by UV. In a follow-up comparative analysis under more complex matrix conditions, 51 surface and 24 wastewater s les pre ost UV treatment were assessed for enteric waterborne HAdV to evaluate the ability of ci-qPCR to reduce the number of false-positive results when compared to conventional qPCR and cell culture. Azo-dye pretreatment of non-UV inactivated s les was shown to improve the ability of molecular HAdV quantification by reducing signals from virions with an accessible genome, thereby increasing the relevance of qPCR results for public health purposes, particularly suited to resource-limited low and middle-income settings.
Methods for assessing long-term mean pathogen count in drinking water and risk management implications
Publisher: IWA Publishing
Date: 08-03-2012
DOI: 10.2166/WH.2012.142
Abstract: Recently pathogen counts in drinking and source waters were shown theoretically to have the discrete Weibull (DW) or closely related discrete growth distribution (DGD). The result was demonstrated versus nine short-term and three simulated long-term water quality datasets. These distributions are highly skewed such that available datasets seldom represent the rare but important high-count events, making estimation of the long-term mean difficult. In the current work the methods, and data record length, required to assess long-term mean microbial count were evaluated by simulation of representative DW and DGD waterborne pathogen count distributions. Also, microbial count data were analyzed spectrally for correlation and cycles. In general, longer data records were required for more highly skewed distributions, conceptually associated with more highly treated water. In particular, 500–1,000 random s les were required for reliable assessment of the population mean ±10%, though 50–100 s les produced an estimate within one log (45%) below. A simple correlated first order model was shown to produce count series with 1/f signal, and such periodicity over many scales was shown in empirical microbial count data, for consideration in s ling. A tiered management strategy is recommended, including a plan for rapid response to unusual levels of routinely-monitored water quality indicators.
Psychological, psychophysiological and behavioural effects of participant-selected vs. researcher-selected music in simulated urban driving
Publisher: Elsevier BV
Date: 10-2021
The transcriptional landscape of plant infection by the rice blast fungus Magnaporthe oryzae reveals distinct families of temporally co-regulated and structurally conserved effectors
Publisher: Oxford University Press (OUP)
Date: 18-02-2023
Abstract: The rice blast fungus Magnaporthe oryzae causes a devastating disease that threatens global rice (Oryza sativa) production. Despite intense study, the biology of plant tissue invasion during blast disease remains poorly understood. Here we report a high-resolution transcriptional profiling study of the entire plant-associated development of the blast fungus. Our analysis revealed major temporal changes in fungal gene expression during plant infection. Pathogen gene expression could be classified into 10 modules of temporally co-expressed genes, providing evidence for the induction of pronounced shifts in primary and secondary metabolism, cell signaling, and transcriptional regulation. A set of 863 genes encoding secreted proteins are differentially expressed at specific stages of infection, and 546 genes named MEP (Magnaportheeffector protein) genes were predicted to encode effectors. Computational prediction of structurally related MEPs, including the MAX effector family, revealed their temporal co-regulation in the same co-expression modules. We characterized 32 MEP genes and demonstrate that Mep effectors are predominantly targeted to the cytoplasm of rice cells via the biotrophic interfacial complex and use a common unconventional secretory pathway. Taken together, our study reveals major changes in gene expression associated with blast disease and identifies a erse repertoire of effectors critical for successful infection.
The fate of legionellae within distribution pipe biofilms: measurement of their persistence, inactivation and detachment
Publisher: IWA Publishing
Date: 06-2004
Abstract: Distribution pipe biofilms present a currently unquantified public health risk to consumers receiving water for domestic potable and non-potable use. The aim of this study was to quantify the numbers of legionellae, used here as model bacterial pathogens, that may accumulate, persist within and detach from distribution pipe biofilms. L. pneumophila recovered by standard culture from an 8 week-old biofilm formed within a novel pilot-scale water distribution system represented 1% of those present in the adjacent bulk water. A combined chlorine concentration exceeding 0.2 mg.L-1 eliminated culturable sessile legionellae altogether, though the reduction in FISH-positive cells represented just 75 ± 25% of the original amount, compared to a 5-log reduction in culturable cells during the same period. Where there was & 0.1 mg.L-1 combined chlorine, an exponential decay/loss of sessile L. pneumophila was observed (k = 0.37 - 0.41) over the course of a 38-day experimental period. The inoculation of the system with 1 μm fluorescent microspheres and legionellae demonstrated that removal of the latter was dominated by chemical disinfection, with erosion and biological grazing playing lesser roles. Under turbulent (Re ∼5000) conditions, larger clusters of biofilm become detached from substrata, with more than 90% of sessile legionellae mobilised into the bulk water phase. Interaction with both biofilms and a thermophilic Acanthamoeba isolate reduced the susceptibility of legionellae to thermal inactivation by between one and two orders of magnitude, though it increased their sensitivity to chemical (free and combined chlorine) disinfection.
Changes in bacterial composition of biofilm in a metropolitan drinking water distribution system
Publisher: Oxford University Press (OUP)
Date: 22-06-2016
DOI: 10.1111/JAM.13150
Abstract: This study examined the development of bacterial biofilms within a metropolitan distribution system. The distribution system is fed with different source water (i.e. groundwater, GW and surface water, SW) and undergoes different treatment processes in separate facilities. The biofilm community was characterized using 16S rRNA gene clone libraries and functional potential analysis, generated from total DNA extracted from coupons in biofilm annular reactors fed with onsite drinking water for up to 18 months. Differences in the bacterial community structure were observed between GW and SW. Representatives that explained the dissimilarity were associated with the classes Betaproteobacteria, Alphaproteobacteria, Actinobacteria, Gammaproteobacteria and Firmicutes. After 9 months the biofilm bacterial community from both GW and SW were dominated by Mycobacterium species. The distribution of the dominant operational taxonomic unit (OTU) (Mycobacterium) positively correlated with the drinking water distribution system (DWDS) temperature. In this study, the biofilm community structure observed between GW and SW were dissimilar, while communities from different locations receiving SW did not show significant differences. The results suggest that source water and/or the water quality shaped by their respective treatment processes may play an important role in shaping the bacterial communities in the distribution system. In addition, several bacterial groups were present in all s les, suggesting that they are an integral part of the core microbiota of this DWDS. These results provide an ecological insight into biofilm bacterial structure in chlorine-treated drinking water influenced by different water sources and their respective treatment processes.
COMPARISON OF THE ABUNDANCE OF THE FECAL STEROL COPROSTANOL AND FECAL BACTERIAL GROUPS IN INNER-SHELF WATERS AND SEDIMENTS NEAR SYDNEY, AUSTRALIA
Publisher: Elsevier BV
Date: 07-1993
DOI: 10.1016/0021-9673(93)80552-J
Abstract: Concurrent measurement of the sewage tracer coprostanol and fecal indicator bacteria were made for water and sediments collected in January 1992 from coastal waters off Sydney, Australia. The coprostanol results were compared with data from an earlier survey conducted in 1989 before the commisioning of Sydney's deepwater ocean outfalls in 1990 and 1991. Good correlations were observed for both water and sediment s les between coprostanol and the two fecal indicator organisms, fecal coliforms and Clostridium perfringens spores, thereby validating the use of coprostanol as a sewage signature in this environment. For sediments, most inner-shelf sites (1-10 km offshore) showed an increase in the concentration of coprostanol between the two surveys. The areas of highest concentration have been shifted further off-shore, to zones adjacent to the diffusers.
A deterministic model to quantify pathogen loads in drinking water catchments: pathogen budget for the Wingecarribee
Publisher: IWA Publishing
Date: 10-2005
Abstract: This paper describes the development and testing of a mathematical model as a tool to quantify pathogen loads in Sydney's drinking water catchments. It has been used to identify, quantify and prioritise sources of Cryptosporidium, Giardia and E. coli in the Wingecarribee catchment. The pathogen model promotes understanding of the relative significance of different sources of pathogen risks as well as their fate and transport as they move through the subcatchments. This pathogen model not only enables water utility managers to identify those catchment segments that may contribute the highest load of pathogens, but also where management options will be most effective.
Evidence for the existence of Cryptosporidium oocysts as single entities in surface runoff
Publisher: IWA Publishing
Date: 10-2005
Abstract: There is uncertainty whether Cryptosporidium oocysts attach to particles or to each other under ambient water conditions. Particle size distributions of Cryptosporidium oocyst suspensions were determined over a range of ionic strengths and pHs to determine under those environmental conditions that may promote oocyst aggregation. Cryptosporidium oocysts were shown to only aggregate in high ionic strength solutions (& .45 M) and remain largely as single entities at ionic strengths and pHs that were likely to be encountered in surface runoff. Similarly, in loam soil suspensions, rather than attaching to the soil particles the majority of oocysts also remained as single entities. Overall, oocysts are expected to remain largely unattached to either themselves or soil particles in overland runoff. This has implications for pathogen transport and modelling since oocysts that are freely suspended are more likely to be transported in runoff to surface waters than if attached to more dense soil/faecal particles.
Assessing the health implications of turbidity and suspended particles in protected catchments
Publisher: IWA Publishing
Date: 07-2004
Abstract: The supply of unfiltered disinfected drinking water from Melbourne's fully protected catchments means that the water-quality managers must ensure that the source water poses no public health risk. High turbidity is currently used as a surrogate of pathogens, and harvesting of water is based on its measurement. The work presented here summarises suspended particle and associated pathogen, microbial indicator and faecal biomarker concentrations collected to (a) quantify turbidity in an Australian water supply system and (b) assess the possibility of increasing water harvesting from selected tributaries. Pathogens and microbial indicators were present in low numbers in these source waters increased turbidity during storm events was not associated with an increase in pathogen concentration. The results confirmed that protected catchments, along with good management, were effective barriers to pathogen contamination. Aesthetic issues still need to be addressed, but no measurable increase in microbiological risk was associated with storm-generated particles.
Complementary independent molecular, radioisotopic and fluorogenic techniques to assess biofilm communities in two wastewater wetlands
Publisher: IWA Publishing
Date: 1999
Screening Level Risk Assessment (SLRA) of human health risks from faecal pathogens associated with a Natural Swimming Pond (NSP)
Publisher: Elsevier BV
Date: 2021
Screening-Level Assays for Potentially Human-Infectious Environmental Legionella spp
Publisher: Springer Science and Business Media LLC
Date: 04-2011
DOI: 10.1007/S12275-011-0233-Z
Abstract: In spite of the fact that various Legionella species are isolated from nonclinical water settings, there is no standard method to determine whether environmental legionellae may be infectious to humans. Here we provide a screening-level approach based on an in vivo murine (A/J mouse) model and three in vitro proliferation assays using Acanthamoeba polyphaga, and THP-1 human and J774 murine macrophage cell lines to identify potentially human-infectious legionellae. As an initial demonstration the infectivity potential of three clinical (Legionella pneumophila, L, longbeacheae, and L. micdadei) and three environmental (L. dumoffii, L. maceachernii, and L. sainthelensi) legionellae were evaluated. A/J mice were intranasally infected and by 6 h post infection (p.L), there were significant bacterial titers in the lungs. L. pneumophila, L. dumoffii, and L. micdadei densities were higher than L. longbeacheae, L. maceacherni, and L. sainthelensi at 24 h p.i. However, only L. pneumophila and L. micdadei persisted in the lungs after 48 h, indicating that the other isolates were rapidly cleared. Results from the in vitro assays showed that only L. pneumophila significantly multiplied within A. polyphaga, THP-1 and J774 cells after 72 h, but lysis of any of the in vitro hosts also flagged the strains for potential concern (e.g. L. dumoffii and L. micdadei). The results demonstrate the value of using multiple approaches to assess the potential level of pathogenicity of Legionella strains isolated from different environmental matrices.
Antimicrobial-resistant microorganisms and their genetic determinants in stormwater: A systematic review
Publisher: Elsevier BV
Date: 08-2020
Legionella Infection during and after the COVID-19 Pandemic
Publisher: American Chemical Society (ACS)
Date: 23-09-2021
Use of a Novel DNA-Loaded Alginate-Calcium Carbonate Biopolymer Surrogate to Study the Engulfment of Legionella pneumophila by Acanthamoeba polyphaga in Water Systems
Publisher: American Society for Microbiology
Date: 31-08-2022
DOI: 10.1128/SPECTRUM.02210-22
Abstract: The internalization of L. pneumophila within amoebae is a critical component of their life cycle in EWS, as it protects the bacteria from commonly used water disinfectants and provides a niche for their replication. Intracellularly replicated forms of L. pneumophila are also more virulent and resistant to sanitizers.
Sub-species typing among bovine C-parvum isolates by PCR-PAGE using a novel microsatellite plus telomere primer scheme
Publisher: IWA Publishing
Date: 07-2002
DOI: 10.2166/WS.2002.0088
Abstract: A PCR-PAGE procedure based on a novel primer set including a previously described microsatellite (M) plus a telomere anchor (+T) was used to biotype C. parvum isolated from bovine sources in three categories: geographically erse, intra herd, and specifically defined. The PAGE patterns resulting from the procedure consisted of from 8 to 18 bands in the 300 to 3,000 bp size range. Application of the procedure revealed widely ergent PAGE banding among the geographically erse s les. Consistent banding patterns were observed among multiple calf hosts from the same dairy herd s led over 1 to 2 year periods. Some differences were observed in PAGE banding between s les in different time periods although all independent s les in each s ling period (up to 5 shown) were homogeneous. Analysis of DNA from s les of the Iowa defined strain of C. parvum isolated in 1998 and in 2000 from the same source (University of Arizona) resulted in PAGE banding that was homogeneous. The sub-type differentiation effectiveness of the M+T PAGE procedure was observed to be substantial. Reference to work being prepared for publication elsewhere indicates that it is similarly effective for Type 1 s les.
Cost, energy, global warming, eutrophication and local human health impacts of community water and sanitation service options
Publisher: Elsevier BV
Date: 02-2017
DOI: 10.1016/J.WATRES.2016.11.044
Abstract: We compared water and sanitation system options for a coastal community across selected sustainability metrics, including environmental impact (i.e., life cycle eutrophication potential, energy consumption, and global warming potential), equivalent annual cost, and local human health impact. We computed normalized metric scores, which we used to discuss the options' strengths and weaknesses, and conducted sensitivity analysis of the scores to changes in variable and uncertain input parameters. The alternative systems, which combined centralized drinking water with sanitation services based on the concepts of energy and nutrient recovery as well as on-site water reuse, had reduced environmental and local human health impacts and costs than the conventional, centralized option. Of the selected sustainability metrics, the greatest advantages of the alternative community water systems (compared to the conventional system) were in terms of local human health impact and eutrophication potential, despite large, outstanding uncertainties. Of the alternative options, the systems with on-site water reuse and energy recovery technologies had the least local human health impact however, the cost of these options was highly variable and the energy consumption was comparable to on-site alternatives without water reuse or energy recovery, due to on-site reuse treatment. Future work should aim to reduce the uncertainty in the energy recovery process and explore the health risks associated with less costly, on-site water treatment options.
Proficiency testing of Cryptosporidium and Giardia, analyses - An Australian case study
Publisher: IWA Publishing
Date: 07-2002
DOI: 10.2166/WS.2002.0083
Abstract: An inter-laboratory proficiency trial was undertaken as a prelude to a survey of Australian drinking source waters for Cryptosporidium and Giardia oo/cysts. Specific aims included measuring the recovery of protozoan control material from representative source waters, identifying laboratory errors and assessing the utility of pre-stained reference oo/cysts. Five experienced laboratories were provided with coded vials containing oo/cysts or blanks for spiking 10 L water s les (11 replicate environmental, 5 filtered) or to be analysed directly (16 Count Control vials). Each laboratory reported both their standard counts and details of how each oo/cyst image was interpreted and confirmed. A sixth laboratory provided flow cytometry prepared seed material and reference analyses. Average recoveries for 10 L s les ranged from 0-67% and 0-72%, for environmental and filtered tap water respectively, depending on laboratory and s le type. The best performing laboratory obtained high recoveries, ranging from 45% to 66% for tap water and 63% to 81% for environmental water. Nonetheless, recovery from tap water and environmental s le analysed simultaneously by the same laboratory could differ markedly (1% v. 48% in one case). Poor recovery and false positives were encountered despite the experience of the participants. Inconsistencies in reporting were introduced by the different procedures for confirming oocysts and cysts. The trial showed that obtaining reliable estimates of environmental protozoan loads is still a concern for water managers.
Exposure to Synthetic Gray Water Inhibits Amoeba Encystation and Alters Expression of Legionella pneumophila Virulence Genes
Publisher: American Society for Microbiology
Date: 15-01-2015
DOI: 10.1128/AEM.03394-14
Abstract: Water conservation efforts have focused on gray water (GW) usage, especially for applications that do not require potable water quality. However, there is a need to better understand environmental pathogens and their free-living amoeba (FLA) hosts within GW, given their growth potential in stored gray water. Using synthetic gray water (sGW) we examined three strains of the water-based pathogen Legionella pneumophila and its FLA hosts Acanthamoeba polyphaga , A. castellanii , and Vermamoeba vermiformis . Exposure to sGW for 72 h resulted in significant inhibition ( P 0.0001) of amoebal encystation versus control-treated cells, with the following percentages of cysts in sGW versus controls: A. polyphaga (0.6 versus 6%), A. castellanii (2 versus 62%), and V. vermiformis (1 versus 92%), suggesting sGW induced maintenance of the actively feeding trophozoite form. During sGW exposure, L. pneumophila culturability decreased as early as 5 h (1.3 to 2.9 log 10 CFU, P 0.001) compared to controls (Δ0 to 0.1 log 10 CFU) with flow cytometric analysis revealing immediate changes in membrane permeability. Furthermore, reverse transcription-quantitative PCR was performed on total RNA isolated from L. pneumophila cells at 0 to 48 h after sGW incubation, and genes associated with virulence ( gacA , lirR , csrA , pla , and sidF ), the type IV secretion system ( lvrB and lvrE ), and metabolism ( ccmF and lolA ) were all shown to be differentially expressed. These results suggest that conditions within GW may promote interactions between water-based pathogens and FLA hosts, through amoebal encystment inhibition and alteration of bacterial gene expression, thus warranting further exploration into FLA and L. pneumophila behavior in GW systems.
Effect of temperature and colonization of Legionella pneumophila and Vermamoeba vermiformis on bacterial community composition of copper drinking water biofilms
Publisher: Wiley
Date: 18-01-2017
Predicting pathogen risks to aid beach management: The real value of quantitative microbial risk assessment (QMRA)
Publisher: Elsevier BV
Date: 09-2010
DOI: 10.1016/J.WATRES.2010.06.048
Abstract: There has been an ongoing dilemma for agencies that set criteria for safe recreational waters in how to provide for a seasonal assessment of a beach site versus guidance for day-to-day management. Typically an overall 'safe' criterion level is derived from epidemiologic studies of sewage-impacted beaches. The decision criterion is based on a percentile value for a single s le or a moving median of a limited number (e.g. five per month) of routine s les, which are reported at least the day after recreator exposure has occurred. The focus of this paper is how to better undertake day-to-day recreational site monitoring and management. Internationally, good ex les exist where predictive empirical regression models (based on rainfall, wind speed/direction, etc.) may provide an estimate of the target faecal indicator density for the day of exposure. However, at recreational swimming sites largely impacted by non-sewage sources of faecal indicators, there is concern that the indicator-illness associations derived from studies at sewage-impacted beaches may be inappropriate. Furthermore, some recent epidemiologic evidence supports the relationship to gastrointestinal (GI) illness with qPCR-derived measures of Bacteroidales/Bacteroides spp. as well as more traditional faecal indicators, but we understand less about the environmental fate of these molecular targets and their relationship to bather risk. Modelling pathogens and indicators within a quantitative microbial risk assessment framework is suggested as a way to explore the large ersity of scenarios for faecal contamination and hydrologic events, such as from waterfowl, agricultural animals, resuspended sediments and from the bathers themselves. Ex les are provided that suggest that more site-specific targets derived by QMRA could provide insight, directly translatable to management actions.
Risk-based enteric pathogen reduction targets for non-potable and direct potable use of roof runoff, stormwater, and greywater
Publisher: Elsevier BV
Date: 04-2017
Procedural outcome of lead explant and countertraction‐assisted femoral lead extraction in Thai patients with cardiac implantable electronic device infection
Publisher: Wiley
Date: 05-08-2021
DOI: 10.1002/JOA3.12574
Abstract: Cardiac implantable electronic device (CIED) implantation rate has been increasing worldwide. Despite proper surgical technique and preincisional intravenous antibiotics, the incidence of infected CIED remains high and leads to serious complications. When encountered with CIED infection, complete CIED system removal is indicated. Several lead extraction approaches have shown a high success rate. However, the facilities are limited in Thailand. In our current practice, we perform lead extraction using the Dotter basket snare femoral approach as our primary method. There are no prior data on this countertraction‐assisted transfemoral technique. Therefore, we aim to study the procedural outcome of countertraction‐assisted transfemoral lead removal technique of CIED infection in Thai patients. Patients diagnosed with CIED infection and with a history of device infection were retrospectively included. Simple manual removal was performed. In case of failure, we proceeded with the modified countertraction‐assisted transfemoral technique. There were 35 patients in the study. The success rate was 94.3%. Most of the leads, 62.8%, were removed by simple manual traction. In the 37.1% who required further femoral approach lead extractions, procedural failure was observed in 5.7% and procedure‐related adverse events in 5.6%. CIED infection‐related death accounted for 5.7% and nosocomial infection‐related death, 2.8%. The success rate of CIED infection lead explant and countertraction‐assisted transfemoral lead extraction technique was high with small complications and can be performed without advanced facilities. However, the procedure required a main center with a cardiovascular thoracic surgery support team.
Human Health Risk Assessment (HHRA) for Environmental Development and Transfer of Antibiotic Resistance
Publisher: Environmental Health Perspectives
Date: 09-2013
DOI: 10.1289/EHP.1206316
Role of hydrophobic and electrostatic interactions for initial enteric virus retention by MF membranes
Publisher: Elsevier BV
Date: 11-2001
Evaluation of Kluyveromyces marxianus as a source of yeast autolysates
Publisher: Oxford University Press (OUP)
Date: 2003
DOI: 10.1007/S10295-002-0008-Y
Abstract: Cells of Kluyveromyces marxianus FII 510700 and Saccharomyces cerevisiae CBS 1907 were autolysed in phosphate buffer, pH 4.5, for a maximum of 10 days to compare chemical changes that occur in the carbohydrate, protein, amino acid and nucleic acid content. Approximately 2.2-3% carbohydrate, 9.5-12% protein, 0.6-1.0% DNA and 6-7% RNA were recovered in the autolysates. The main amino acids were beta-alanine, phenylalanine, cysteine, methionine, glutamic acid and isoleucine. No significant differences in the yeast autolysates of K. marxianus and S. cerevisiae were observed. Consequently, K. marxianus produced from lactose-based media has potential as a source of yeast autolysates used in the food industry.
Impacts of Migratory Sandhill Cranes (Grus canadensis) on Microbial Water Quality in the Central Platte River, Nebraska, USA (vol 224, 1576, 2013)
Publisher: Springer Science and Business Media LLC
Date: 02-2022
Editorial Important news about this journal
Publisher: IWA Publishing
Date: 04-03-2021
DOI: 10.2166/WP.2021.000
Hydrogen sulphide production tests and the detection of groundwater faecal contamination by septic seepage
Publisher: IWA Publishing
Date: 05-2005
Abstract: The ‘H2S test’ is being advanced for microbiological water quality testing where conventional coliform based methods are impractical or too expensive. It involves ambient temperature incubation of water s les with nutrient formulated to generate hydrogen sulphide when ‘faecal’ bacteria are present. Recently a WHO review identified several concerns including the limited number of comparative studies, formulation variability, and false positives and negatives. In response we have compared the H2S test's ability to detect and quantify faecal contamination in an aquifer impacted by septic tank leachfields with measurements obtained concurrently using conventional bacterial indicators, coliphages, faecal sterol biomarkers, Cryptosporidium and Giardia. Like these other analytes, H2S testing detected a contamination gradient ranging from high (septic liquid) to moderate (exfiltration zones), to background (e.g. domestic bores), corresponding to indicator removal + dilution by factors & . Presence/absence tests could not distinguish between heavily and slightly contaminated waters, whereas multi-tube testing (e.g. 10 × 10 mL arrays) did. It was concluded that while the WHO review concerns are justified, the H2S test performance shows promise in sanitary survey work, can be improved by employing an mpn approach and has potential to aid in the protection of source water and identifying contaminated groundwater.
Biofilms in an urban water distribution system: measurement of biofilm biomass, pathogens and pathogen persistence within the Greater Stockholm area, Sweden
Publisher: IWA Publishing
Date: 10-2005
Abstract: Distribution pipe biofilms can provide sites for the concentration of a wide range of microbial pathogens, thereby acting as a potential source of continual microbial exposure and furthermore can affect the aesthetic quality of water. In a joint project between Stockholm Water, the MISTRA “Sustainable Urban Water” program, the Swedish Institute for Infectious Disease Control and the Royal Technical University, Stockholm, the aim of the current study was to investigate biofilms formed in an urban water distribution system, and quantify the impact of such biofilms on potential pathogen accumulation and persistence within the Greater Stockholm Area, Sweden. When used for primary disinfection, ultra-violet (UV) treatment had no measurable influence on biofilm formation within the distribution system when compared to conventional chlorination. Biofilms produced within a model pilot-plant were found to be representative to those that had formed within the larger municipal water distribution system, demonstrating the applicability of the novel pilot-plant for future studies. Polystyrene microspheres (1.0μm) and Salmonella bacteriophages demonstrated their ability to accumulate and persist within the model pilot-plant system, where the means of primary disinfection (UV-treatment, chlorination) had no influence on such phenomena. With the exception of aeromonads, potential pathogens and faecal indicators could not be detected within biofilms from the Stockholm water distribution system. Results from this investigation may provide information for water treatment and distribution management strategies, and fill key data gaps that presently hinder the refinement of microbial risk models.
Relationships between indicators, pathogens and water quality in an estuarine system
Publisher: Elsevier BV
Date: 09-1996
Molecular Detection of Legionella spp. and their associations with Mycobacterium spp., Pseudomonas aeruginosa and amoeba hosts in a drinking water distribution system
Publisher: Oxford University Press (OUP)
Date: 05-01-2016
DOI: 10.1111/JAM.12996
Abstract: This study investigated waterborne opportunistic pathogens (OPs) including potential hosts, and evaluated the use of Legionella spp. for indicating microbial water quality for OPs within a full-scale operating drinking water distribution system (DWDS). To investigate the occurrence of specific microbial pathogens within a major city DWDS we examined large volume (90 l drinking water) ultrafiltration (UF) concentrates collected from six sites between February, 2012 and June, 2013. The detection frequency and concentration estimates by qPCR were: Legionella spp. (57%/85 cell equivalent, CE l(-1) ), Mycobacterium spp. (88%/324 CE l(-1) ), Pseudomonas aeruginosa (24%/2 CE l(-1) ), Vermamoeba vermiformis (24%/2 CE l(-1) ) and Acanthamoeba spp. (42%/5 cyst equivalent, CE l(-1) ). There was no detection of the following microorganisms: human faecal indicator Bacteroides (HF183), Salmonella enterica, C ylobacter spp., Escherichia coli O157:H7, Giardia intestinalis, Cryptosporidium spp. or Naegleria fowleri. There were significant correlations between the qPCR signals of Legionella spp. and Mycobacterium spp., and their potential hosts V. vermiformis and Acanthamoeba spp. Sequencing of Legionella spp. demonstrated limited ersity, with most sequences coming from two dominant groups, of which the larger dominant group was an unidentified species. Other known species including Legionella pneumophila were detected, but at low frequency. The densities of Legionella spp. and Mycobacterium spp. were generally higher (17 and 324 folds, respectively) for distal sites relative to the entry point to the DWDS. Legionella spp. occurred, had significant growth and were strongly associated with free-living amoebae (FLA) and Mycobacterium spp., suggesting that Legionella spp. could provide a useful DWDS monitoring role to indicate potential conditions for non-faecal OPs. The results provide insight into microbial pathogen detection that may aid in the monitoring of microbial water quality within DWDS prior to customer exposures.
Particle dispersion for further Cryptosporidium and Giardia detection by flow cytometry
Publisher: Oxford University Press (OUP)
Date: 09-2003
DOI: 10.1046/J.1472-765X.2003.01381.X
Abstract: The aim of this study was to overcome the analytical problems encountered during the detection of protozoans by flow cytometry resulting from particle compaction. Malvern Mastersizer (Malvern Instruments, Malvern, UK) was used to characterize the particle distribution of four different water s les and/or particle concentrates incubated with (i) low ionic strength solution or sequestring agent, (ii) anionic or non-ionic surfactants (iii) industry detergent formulations and (iv) physical treatment. The recovery of oocysts and cysts in seeded and treated particle concentrates was estimated by cytometry and microscopy. The decrease in ionic strength of the aqueous solution was most efficient in particle dispersion for different types of water. Moreover, s les treated with deionized water or tetrasodium pyrophosphate showed the highest recovery with more than 80% of the oocysts and cysts recovered. Chemical treatments that act by altering the ionic strength of the medium are the most efficient for all water types tested here but the overall detergency performance cannot be predicted for all water types. Flow cytometric detection has been replaced largely by immunomagnetic separation but the data recorded still have relevance in this technique as well as in molecular techniques requiring DNA or RNA extraction.
Enrichment of autotrophic anaerobic ammonium-oxidizing consortia from various wastewaters
Publisher: Springer Science and Business Media LLC
Date: 02-2002
DOI: 10.1007/S00248-001-0033-9
Abstract: The option for biological nitrogen removal has recently been broadened with the description of simultaneous nitrification/denitrification, anaerobic ammonium oxidation (ANAMMOX) and the concept of CANON (completely autotrophic nitrogen removal over nitrite). An autotrophic anaerobic ammonium oxidation (AAAO) consortium was successfully selected and enriched from municipal treatment plant sludges in Sydney, Australia, but not from industrial coke-oven wastewater sludges. Chemolithoautotrophic basic salt (CLABS) medium was used in the selection of AAAO organisms and chlor henicol was added to the initial stage of selection to eliminate denitrifiers. Two different temperatures, 37 degrees C and 55 degrees C, were used in the selection of mesophilic and thermophilic consortia, respectively. Thermophilic AAAO organisms were not selected at 55 degrees C. Mesophilic AAAO activities, however, were evident in both batch and continuous cultures, whereby ammonium was consumed concurrently with a decrease of nitrite, giving a ratio of 1:1-1:1.3 in ammonium removal rate over nitrite consumption rate. A continuous-mode mesophilic fixed-bed reactor was established to enrich the AAAO consortium. After 1 year, biofilms, pinkish in color, had developed on the support media and side wall of the feed-line tubing. Ammonium and nitrite consumption increased from approximately 15 mg to 60 mg d(-1) L(-1) over a period of 243 days. Later, transmission electron microscopy (TEM) and fluorescence in situ hybridization (FISH) techniques revealed that the dominant cell type in the AAAO consortium had a similar morphology and 16S rDNA sequence homology to that of the recently described ANAMMOX organism, "Brocadia anammoxidans".
Rapid method for fluorescentin situribosomal RNA labelling ofCryptosporidium parvum
Publisher: Oxford University Press (OUP)
Date: 11-1998
DOI: 10.1046/J.1365-2672.1998.00589.X
Abstract: A method for fluorescence in situ hybridization (FISH) is described that requires less than 1 h duration. Oocysts were resuspended in 50% ethanol and incubated at 80 degrees C for 10 min for simultaneous fixation and permeabilization. S les were than incubated with the oligonucleotide probe at 48 degrees C for more than 30 min. The rRNA binding specificity of the optimized protocol was confirmed. FISH was found to be valuable as a second label for oocysts presumptively identified immunofluorescently, but required more than an order of magnitude signal lification for independent use. The number of oligonucleotide probes bound per oocyst was compared with the copy number of 18S rRNA molecules per oocyst to provide a measure of the labelling efficiency of the FISH method. Hybridization kinetics were also analysed. These data indicate that significant further increases in the brightness of FISH-labelled oocysts cannot be achieved by further optimization of the pre-treatment and hybridization conditions.
Knowledge Gaps in the Understanding of Antimicrobial Resistance in Canada
Publisher: Frontiers Media SA
Date: 20-10-2021
DOI: 10.3389/FPUBH.2021.726484
Abstract: Current limitations in the understanding and control of antimicrobial resistance (AMR) in Canada are described through a comprehensive review focusing on: (1) treatment optimization (2) surveillance of antimicrobial use and AMR and (3) prevention of transmission of AMR. Without addressing gaps in identified areas, sustained progress in AMR mitigation is unlikely. Expert opinions and perspectives contributed to prioritizing identified gaps. Using Canada as an ex le, this review emphasizes the importance and necessity of a One Health approach for understanding and mitigating AMR. Specifically, antimicrobial use in human, animal, crop, and environmental sectors cannot be regarded as independent therefore, a One Health approach is needed in AMR research and understanding, current surveillance efforts, and policy. Discussions regarding addressing described knowledge gaps are separated into four categories: (1) further research (2) increased capacity/resources (3) increased prescriber/end-user knowledge and (4) policy development/enforcement. This review highlights the research and increased capacity and resources to generate new knowledge and implement recommendations needed to address all identified gaps, including economic, social, and environmental considerations. More prescriber/end-user knowledge and policy development/enforcement are needed, but must be informed by realistic recommendations, with input from all relevant stakeholders. For most knowledge gaps, important next steps are uncertain. In conclusion, identified knowledge gaps underlined the need for AMR policy decisions to be considered in a One Health framework, while highlighting critical needs to achieve realistic and meaningful progress.
Counting Legionella Cells within Single Amoeba Host Cells
Publisher: American Society for Microbiology
Date: 15-03-2012
DOI: 10.1128/AEM.07392-11
Abstract: Here we present the first attempt to quantify Legionella pneumophila cell numbers within in idual amoeba hosts that may be released into engineered water systems. The maximum numbers of culturable L. pneumophila cells grown within Acanthamoeba polyphaga and Naegleria fowleri were 1,348 (mean, 329) and 385 (mean, 44) CFU trophozoite −1 , respectively.
Interactive effects of task load and music tempo on psychological, psychophysiological, and behavioural outcomes during simulated driving.
Publisher: Informa UK Limited
Date: 17-01-2022
DOI: 10.1080/00140139.2021.2003872
Abstract: We examined the interactive effects of task load and music tempo on cognition, affect, cardiac response, and safety-relevant behaviour during simulated driving. Using a counterbalanced, within-subjects design, participants (
Long-term continuous partial nitritation-anammox reactor aeration optimization at different nitrogen loading rates for the treatment of ammonium rich digestate lagoon supernatant
Publisher: Elsevier BV
Date: 12-2020
Automated event sampling for microbiological and related analytes in remote sites: A comprehensive system
Publisher: IWA Publishing
Date: 07-2002
DOI: 10.2166/WS.2002.0094
Abstract: Pathogen concentrations are most often monitored during dry weather. Generally in Australia, however, loads mobilised during storms are of more concern. The filling of reservoirs commonly occurs from heavy rain events, and flood inputs may destabilise reservoir hydraulics leading to short-circuiting of contaminates to water supply off-takes. To capture storm events that can occur rapidly in remote locations at any time, automated s ling would seem appropriate. Unfortunately no commercial s ling system appears suitable for collecting multiple large volume s les along a hydrograph. We report here the development of an Event S ling System (ESS) and associated resources, designed to address the special needs of microbiological s ling and varying event and site characteristics. The resultant ESSs consist of a standardised s ling module, enclosed in housings suited to different circumstances that is currently being field tested at six sites. S ling module components include ISCO s lers modified to collect 24 ten litre ambient and 24 one litre refrigerated s les at remote sites along with in situ stream data. Essential to this hardware are s le collection and ESS management protocols covering issues such as storm warning, collection team mobilisation, laboratory coordination, ESS commissioning and maintenance. Some issues remain to be addressed, hence the resulting ESSs are seen as prototypes in the development of standardised storm-event based microbiological s ling well suited to remote locations.
Evaluating Microbial and Chemical Hazards in Commercial Struvite Recovered from Wastewater
Publisher: American Chemical Society (ACS)
Date: 09-04-2019
Abstract: Controlled struvite (NH
Are sewage treatment plants promoting antibiotic resistance?
Publisher: Informa UK Limited
Date: 31-01-2011
Point-of-use water disinfection using ultraviolet and visible light-emitting diodes
Publisher: Elsevier BV
Date: 05-2016
DOI: 10.1016/J.SCITOTENV.2016.02.039
Abstract: Improvements in point-of-use (POU) drinking water disinfection technologies for remote and regional communities are urgently needed. Conceptually, UV-C light-emitting diodes (LEDs) overcome many drawbacks of low-pressure mercury tube based UV devices, and UV-A or visible light LEDs also show potential. To realistically evaluate the promise of LED disinfection, our study assessed the performance of a model 1.3 L reactor, similar in size to solar disinfection bottles. In all, 12 different commercial or semi-commercial LED arrays (270-740 nm) were compared for their ability to inactivate Escherichia coli K12 ATCC W3110 and Enterococcus faecalis ATCC 19433 over 6h. Five log10 and greater reductions were consistently achieved using the 270, 365, 385 and 405 nm arrays. The output of the 310 nm array was insufficient for useful disinfection while 430 and 455 nm performance was marginal (≈ 4.2 and 2.3-log10s E. coli and E. faecalis over the 6h). No significant disinfection was observed with the 525, 590, 623, 660 and 740 nm arrays. Delays in log-phase inactivation of E. coli were observed, particularly with UV-A wavelengths. The radiation doses required for >3-log10 reduction of E. coli and E. faecalis differed by 10 fold at 270 nm but only 1.5-2.5 fold at 365-455 nm. Action spectra, consistent with the literature, were observed with both indicators. The design process revealed cost and technical constraints pertaining to LED electrical efficiency, availability and lifetime. We concluded that POU LED disinfection using existing LED technology is already technically possible. UV-C LEDs offer speed and energy demand advantages, while UV-A/violet units are safer. Both approaches still require further costing and engineering development. Our study provides data needed for such work.
Aggregating local, regional and global burden of disease impact assessment: detecting potential problem shifting in air quality policy making
Publisher: Springer Science and Business Media LLC
Date: 02-03-2017
Pathogen monitoring offers questionable protection against drinking-water risks: A QMRA (Quantitative Microbial Risk Analysis) approach to assess management strategies
Publisher: IWA Publishing
Date: 08-2006
DOI: 10.2166/WST.2006.478
Abstract: Risk mitigation provided by human monitoring and control over a water supply system has been consistently overlooked when estimating pathogen exposure to consumers. The Systems-Actions-Management (SAM) framework lends itself neatly to Quantitative Microbial Risk Assessment (QMRA) as one way to establish this link. The general premise is that an organisational protocol will influence how a human controller behaves, in turn influencing the system performance. For illustrative purposes, the framework was applied to a hypothetical water supply system to quantify the risk reduction offered by routine Cryptosporidium monitoring and the response to oocyst ‘detects’. Our findings suggest that infrequent direct pathogen monitoring may provide a negligible risk barrier. The practice of s ling treated water to verify microbiological integrity is also dubious: oocyst densities were largely under-estimated, in part due to the spatial dispersion of oocysts in the waterbody, but predominantly from imperfect detection methods. The development of ‘event-driven’ monitoring schemes with barrier performance-based treatment verification methods, as promoted in new guidelines, is supported as a pressing issue to reduce the likelihood of undetected pathogen passage through a treatment plant.
Microbial exposure assessment of an urban recreational lake: a case study of the application of new risk-based guidelines
Publisher: IWA Publishing
Date: 08-2006
DOI: 10.2166/WST.2006.476
Abstract: New WHO and Australian guidelines promote a risk-management approach for minimising exposure to pathogens in recreational waters. Between 2003 and 2005, they were applied to Lake Parramatta (10 ha, 450 ML), a potential recreation site in Sydney, Australia. A three stage approach was developed involving (1) initial suitability assessment using historic data, (2) revised suitability assessment based on new data and (3) characterisation of hazardous (especially wet weather) events. Contrary to the stage 1 suitability classification, stage 2 baseline data indicated that during dry weather the lake had water quality sufficient for primary contact recreation (95th percentiles for enterococci=19 MPN/100, n=50) and the major pathogen source was wildfowl. Guideline principles provided a rationale for collecting microbiological and geographic data needed to understand local cycles of lake contamination/recovery. The concept of hazardous events was particularly useful. Studies of stormwater events led us to identify a transition point (& mm rainfall in 24 h) where human-faecal pathogen risks increased and access needed to be controlled. Together baseline and event data yielded operational tools (i.e. event detection methods, action triggers, auditing criteria, remediation priorities) for minimising bather exposure.
Microbial risk and removal—a utility perspective
Publisher: IWA Publishing
Date: 08-2006
DOI: 10.2166/WST.2006.477
Abstract: In this paper the results of a s ling programme, undertaken as part of the EU MicroRisk project, are described. This project was undertaken to ascertain the occurrence of pathogens and indicators in the River Thames and their subsequent removal through a treatment works. Appropriate physico-chemical surrogates, as determined by statistical correlation are proposed for the microorganisms identified in the raw water. This study shows that under normal raw water conditions the treatment works is able to remove microbial contamination with a significant margin of safety.
Preferential colonization and release of Legionella pneumophila from mature drinking water biofilms grown on copper versus unplasticized polyvinylchloride coupons
Publisher: Elsevier BV
Date: 03-2014
DOI: 10.1016/J.IJHEH.2013.04.005
Abstract: Legionella occurrence in premise drinking water (DW) systems contributes to legionellosis outbreaks, especially in the presence of suitable protozoan hosts. This study examined L. pneumophila behavior within DW biofilms grown on copper (Cu) and unplasticized polyvinylchloride (uPVC) surfaces in the presence of Acanthamoeba polyphaga. One year-old DW biofilms were established within six CDC biofilm reactors: three each containing Cu or uPVC coupons. Biofilms were then inoculated with L. pneumophila (uPVC-Lp and Cu-Lp), or L. pneumophila and A. polyphaga (uPVC-Lp/Ap and Cu-Lp/Ap) and compared to sterile water inoculated controls (uPVC- and Cu-Control) over a 4 month period. L. pneumophila appeared more persistent by qPCR within Cu biofilms in the presence of A. polyphaga compared to uPVC biofilms with or without A. polyphaga, but maintained their cultivability in uPVC biofilms compared to Cu biofilms. Also, persistent shedding of L. pneumophila cells (assayed by qPCR) in the effluent water implied colonization of L. pneumophila within Cu-coupon reactors compared to no detection from uPVC-coupon reactor effluent 14 days after inoculation. Hence, L. pneumophila appeared to colonize Cu surfaces more effectively and may be shed from the biofilms at a greater frequency and duration compared to L. pneumophila colonized uPVC surfaces with host amoebae playing a role in L. pneumophila persistence within Cu biofilms.
Long-term persistence of infectious Legionella with free-living amoebae in drinking water biofilms
Publisher: Elsevier BV
Date: 05-2019
DOI: 10.1016/J.IJHEH.2019.04.007
Abstract: Prolific growth of pathogenic Legionella pneumophila within engineered water systems and premise plumbing, and human exposure to aerosols containing this bacterium results in the leading health burden of any water-related pathogen in developed regions. Ecologically, free-living amoebae (FLA) are an important group of the microbial community that influence biofilm bacterial ersity in the piped-water environment. Using fluorescent microscopy, we studied in-situ the colonization of L. pneumophila in the presence of two water-related FLA species, Willaertia magna and Acanthamoeba polyphaga in drinking water biofilms. During water flow as well as after periods of long-stagnation, the attachment and colonization of L. pneumophila to predeveloped water-biofilm was limited. Furthermore, W. magna and A. polyphaga showed no immediate interactions with L. pneumophila when introduced to the same natural biofilm environment. A. polyphaga encysted within 5-7 d after introduction to the tap-water biofilms and mostly persisted in cysts till the end of the study period (850 d). W. magna trophozoites, however, exhibited a time delay in feeding on Legionella and were observed with internalized L. pneumophila cells after 3 weeks from their introduction to the end of the study period and supported putative (yet limited) intracellular growth. The culturable L.pneumophila in the bulk water was reduced by 2-log over 2 years at room temperature but increased (without a change in mip gene copies by qPCR) when the temperature was elevated to 40 °C within the same closed-loop tap-water system without the addition of nutrients or fresh water. The overall results suggest that L. pneumophila maintains an ecological balance with FLA within the biofilm environment, and higher temperature improve the viability of L. pneumophila cells, and intracellular growth of Legionella is possibly cell-concentration dependent. Observing the preferential feeding behavior, we hypothesize that an initial increase of FLA numbers through feeding on a range of other available bacteria could lead to an enrichment of L. pneumophila, and later force predation of Legionella by the amoeba trophozoites results in rapid intracellular replication, leading to problematic concentration of L. pneumophila in water. In order to find sustainable control options for legionellae and various other saprozoic, amoeba-resisting bacterial pathogens, this work emphasizes the need for better understanding of the FLA feeding behavior and the range of ecological interactions impacting microbial population dynamics within engineered water systems.
APPLICATION OF FLOW CYTOMETRIC METHODS FOR THE ROUTINE DETECTION OF CRYPTOSPORIDIUM AND GIARDIA IN WATER
Publisher: Wiley
Date: 05-1994
Abstract: Cryptosporidium and Giardia are common causes of waterborne disease. The currently used methods of detecting these organisms in water rely on filtration capture, immunofluorescence labelling, and epifluorescence microscopy. These methods are inefficient, labour intensive, and require a highly skilled microscopist. We describe an alternative technique using flocculation concentration, followed by flow cytometry with fluorescence activated cell sorting. Environmental s les were analysed, and protozoan-like particles were sorted and collected before confirmation with epifluorescence microscopy. The technique was found to be significantly more sensitive and considerably faster than the conventional methods.
Pathogen performance testing of a natural swimming pool using a cocktail of microbiological surrogates and QMRA-derived management goals
Publisher: IWA Publishing
Date: 08-06-2021
DOI: 10.2166/WH.2021.015
Abstract: In recent decades, natural swimming pools (NSPs) have gained popularity in Europe, especially in Germany and Austria. NSPs differ from swimming pools in that they utilize biological treatment processes based on wetland processes with no disinfection residual. However, data are missing on the specific log-reduction performance of NSPs to address enteric virus, bacteria, and parasitic protozoa removal considered necessary to meet the North American risk-based benchmark (& illnesses per 1,000 swimming events) set by the USEPA for voluntary swimming. In this study, we examined Canada's first NSP at Borden Park, Edmonton, Canada, to address the following three questions: (1) Given normal faecal shedding rates by bathers, what is the total log reduction (TLR) theoretically needed to meet the EPA benchmark? (2) what is the in-situ performance of the NSP based on spiking suitable microbial surrogates (MS2 coliphage, Enterococcus faecalis, and Saccharomyces cerevisiae [Baker's yeast])? and (3) how much time is required to reach acceptable bather risk levels under different representative volume-turnover rates? A reverse-quantitative microbial risk assessment (QMRA) revealed that of the four reference pathogens selected (Norovirus, C ylobacter, Cryptosporidium, and Giardia), only Norovirus was estimated to exceed the risk benchmark at the 50th, 75th, and 95th percentiles, while C ylobacter was the only other reference pathogen to exceed at the 95th percentile. Log-reduction values (LRVs) were similar to previous reports for bacterial indicators, and novel LRVs were estimated for the other two surrogates. A key finding was that more than 24 h treatment time would be necessary to provide acceptable bather protection following heavy bather use (378 bathers/day for main pool and 26 bathers/day for children's pool), due to the mixing dynamics of the treated water diluting out possible residual pool faecal contamination. The theoretical maximum number of people in the pool per day to be below USEPA's 35 gastro cases in 1,000 swimming events was 113, 47, and 8, at the 50th, 75th, and 95th percentiles. Further, the use of ultra-violet disinfection to the pool return flow had little effect on reducing the treatment time required.
The use of a ribosomal RNA targeted oligonucleotide probe for fluorescent labelling of viable Cryptosporidium parvum oocysts
Publisher: Oxford University Press (OUP)
Date: 09-1998
DOI: 10.1046/J.1365-2672.1998.853496.X
Abstract: A fluorescence in situ hybridization (FISH) technique has been developed for the fluorescent labelling of Cryptosporidium parvum oocysts in water s les. The FISH technique employs a fluorescently labelled oligonucleotide probe (Cry1 probe) targeting a specific sequence in the 18S ribosomal RNA (rRNA) of C. parvum. Hybridization with the Cry1 probe resulted in fluorescence of sporozoites within oocysts that were capable of excystation, while oocysts that were dead prior to fixation did not fluoresce. Correlation of the FISH method with viability as measured by in vitro excystation was statistically highly significant, with a calculated correlation coefficient of 0.998. Examination of sequence data for Cryptosporidium spp. other than C. parvum suggests that the Cry1 probe is C. parvum-specific. In addition, 19 isolates of C. parvum were tested, and all fluoresced after hybridization with the Cry1 probe. Conversely, isolates of C. baileyi and C. muris were tested and found not to fluoresce after hybridization with the Cry1 probe. The fluorescence of FISH-stained oocysts was not bright enough to enable detection of oocysts in environmental water concentrates containing autofluorescent algae and mineral particles. However, in combination with immunofluorescence staining, FISH enabled species-specific detection and viability determination of C. parvum oocysts in water s les.
Environmental inactivation of Cryptosporidium oocysts in catchment soils
Publisher: Oxford University Press (OUP)
Date: 11-2015
DOI: 10.1111/J.1365-2672.2004.02459.X
Abstract: To generate field-relevant inactivation rates for Cryptosporidium oocysts in soil that may serve as parameter values in models to predict the terrestrial fate and transport of oocysts in catchments. The inactivation of Cryptosporidium oocysts in closed soil microcosms over time was monitored using fluorescence in situ hybridization (FISH) as an estimate of oocyst 'viability'. Inactivation rates for Cryptosporidium in two soils were determined under a range of temperature, moisture and biotic status regimes. Temperature and soil type emerged as significantly influential factors (P < 0.05) for Cryptosporidium inactivation. In particular, temperatures as high as 35 degrees C may result in enhanced inactivation. When modelling the fate of Cryptosporidium oocysts in catchment soils, the use of inactivation rates that are appropriate for the specific catchment climate and soil types is essential. FISH was considered cost-effective and appropriate for determining oocyst inactivation rates in soil. Previous models for predicting the fate of pathogens in catchments have either made nonvalidated assumptions regarding inactivation of Cryptosporidium in the terrestrial environment or have not considered it at all. Field-relevant inactivation data are presented, with significant implications for the management of catchments in warm temperate and tropical environments.
UV inactivation of human infectious viruses at two full-scale wastewater treatment plants in Canada
Publisher: Elsevier BV
Date: 12-2018
DOI: 10.1016/J.WATRES.2018.09.057
Abstract: Ultraviolet (UV) disinfection is widely used to inactivate microorganisms prior to release of treated municipal wastewater. However, limited data are available for in situ inactivation of infectious enteric viruses by UV treatment at full-scale. In this study, a total of 51 pre-UV and 50 post-UV s les were collected over a two-year period from two wastewater treatment plants (WWTPs) and analyzed for noroviruses, rotavirus, reovirus, sapovirus, astrovirus, enteroviruses, adenoviruses and JC virus. Both pre-UV and post-UV s les had relatively high concentrations of these viruses determined by qPCR. Infectious viruses were also observed in 98% of pre-UV s les and 76% of post-UV s les by cell culture, using either cytopathic effect (CPE) or integrated cell culture with qPCR (ICC-qPCR). Reovirus was the most common virus detected by ICC-qPCR, present in 92% of pre-UV and 48% of post-UV s les. Infectious enterovirus and adenovirus were detected by ICC-qPCR in 33% and 31% of pre-UV s les, 14% and 20% of post-UV s les, respectively. Mean log
UV Disinfection of Hand-Rinse Greywater and Performance Testing Using Indigenous Staphylococcus spp
Publisher: MDPI AG
Date: 11-12-2017
DOI: 10.3390/W9120963
Accumulation and fate of microorganisms and microspheres in biofilms formed in a pilot-scale water distribution system
Publisher: American Society for Microbiology
Date: 02-2005
DOI: 10.1128/AEM.71.2.706-712.2005
Abstract: The accumulation and fate of model microbial “pathogens” within a drinking-water distribution system was investigated in naturally grown biofilms formed in a novel pilot-scale water distribution system provided with chlorinated and UV-treated water. Biofilms were exposed to 1-μm hydrophilic and hydrophobic microspheres, Salmonella bacteriophages 28B, and Legionella pneumophila bacteria, and their fate was monitored over a 38-day period. The accumulation of model pathogens was generally independent of the biofilm cell density and was shown to be dependent on particle surface properties, where hydrophilic spheres accumulated to a larger extent than hydrophobic ones. A higher accumulation of culturable legionellae was measured in the chlorinated system compared to the UV-treated system with increasing residence time. The fate of spheres and fluorescence in situ hybridization-positive legionellae was similar and independent of the primary disinfectant applied and water residence time. The more rapid loss of culturable legionellae compared to the fluorescence in situ hybridization-positive legionellae was attributed to a loss in culturability rather than physical desorption. Loss of bacteriophage 28B plaque-forming ability together with erosion may have affected their fate within biofilms in the pilot-scale distribution system. The current study has demonstrated that desorption was one of the primary mechanisms affecting the loss of microspheres, legionellae, and bacteriophage from biofilms within a pilot-scale distribution system as well as disinfection and biological grazing. In general, two primary disinfection regimens (chlorination and UV treatment) were not shown to have a measurable impact on the accumulation and fate of model microbial pathogens within a water distribution system.
Chemical contaminants in feedlot wastes: Concentrations, effects and attenuation
Publisher: Elsevier BV
Date: 08-2008
DOI: 10.1016/J.ENVINT.2007.10.007
Abstract: Commercial feedlots for beef cattle finishing are potential sources of a range of trace chemicals which have human health or environmental significance. To ensure adequate protection of human and environmental health from exposure to these chemicals, the application of effective manure and effluent management practices is warranted. The Australian meat and livestock industry has adopted a proactive approach to the identification of best management practices. Accordingly, this review was undertaken to identify key chemical species that may require consideration in the development of guidelines for feedlot manure and effluent management practices in Australia. Important classes of trace chemicals identified include steroidal hormones, antibiotics, ectoparasiticides, mycotoxins, heavy metals and dioxins. These are described in terms of their likely sources, expected concentrations and public health or environmental significance based on international data and research. Androgenic hormones such as testosterone and trenbolone are significantly active in feedlot wastes, but they are poorly understood in terms of fate and environmental implications. The careful management of residues of antibiotics including virginiamycin, tylosin and oxytetracycline appears prudent in terms of minimising the risk of potential public health impacts from resistant strains of bacteria. Good management of ectoparasiticides including synthetic pyrethroids, macrocyclic lactones, fluazuron, and amitraz is important for the prevention of potential ecological implications, particularly towards dung beetles. Very few of these in idual chemical contaminants have been thoroughly investigated in terms of concentrations, effects and attenuation in Australian feedlot wastes.
Technologic resilience assessment of coastal community water and wastewater service options
Publisher: Elsevier BV
Date: 09-2015
Development of an Escherichia coli K12-specific quantitative polymerase chain reaction assay and DNA isolation suited to biofilms associated with iron drinking water pipe corrosion products
Publisher: IWA Publishing
Date: 06-06-2014
DOI: 10.2166/WH.2014.203
Abstract: A quantitative polymerase chain reaction assay (115 bp licon) specific to Escherichia coli K12 with an ABITM internal control was developed based on sequence data encoding the rfb gene cluster. Assay specificity was evaluated using three E. coli K12 strains (ATCC W3110, MG1655 & DH1), 24 non-K12 E. coli and 23 bacterial genera. The biofilm detection limit was 103 colony-forming units (CFU) E. coli K12 mL−1, but required a modified protocol, which included a bio-blocker Pseudomonas aeruginosa with ethylenediaminetetraacetic acid buffered to pH 5 prior to cell lysis/DNA extraction. The novel protocol yielded the same sensitivity for drinking water biofilms associated with Fe3O4 (magnetite)-coated SiO2 (quartz) grains and biofilm-surface iron corrosion products from a drinking water distribution system. The novel DNA extraction protocol and specific E. coli K12 assay are sensitive and robust enough for detection and quantification within iron drinking water pipe biofilms, and are particularly well suited for studying enteric bacterial interactions within biofilms.
Nutrient recovery from source-diverted blackwater: Optimization for enhanced phosphorus recovery and reduced co-precipitation
Publisher: Elsevier BV
Date: 10-2019
Can off-river water and shade provision reduce cattle intrusion into drinking water catchment riparian zones?
Publisher: Elsevier BV
Date: 12-2013
Editorial: Important news about this journal
Publisher: IWA Publishing
Date: 03-03-2021
DOI: 10.2166/WPT.2021.000
Microbial challenge-testing of treatment processes for quantifying stormwater recycling risks and management
Publisher: IWA Publishing
Date: 03-2008
DOI: 10.2166/WST.2008.194
Abstract: Pathogenic microorganisms have been identified as the main human health risks associated with the reuse of treated urban stormwater (runoff from paved and unpaved urban areas). As part of the Smart Water initiative (Victorian Government, Australia), a collaborative evaluation of three existing integrated stormwater recycling systems, and the risks involved in non-potable reuse of treated urban stormwater is being undertaken. Three stormwater recycling systems were selected at urban locations to provide a range of barriers including biofiltration, storage tanks, UV disinfection, a constructed wetland, and retention ponds. Recycled water from each of the systems is used for open space irrigation. In order to adequately undertake exposure assessments, it was necessary to quantify the efficacy of key barriers in each exposure pathway. Given that none of the selected treatment systems had previously been evaluated for their treatment efficiency, experimental work was carried out comprising dry and wet weather monitoring of each system (for a period of 12 months), as well as challenging the barriers with model microbes (for viruses, bacteria and parasitic protozoa) to provide input data for use in Quantitative Microbial Risk Assessment.
Editorial: Important news about this journal
Publisher: IWA Publishing
Date: 03-2021
DOI: 10.2166/WS.2021.000
Role of amoebae for survival and recovery of 'non-culturable' Helicobacter pylori cells in aquatic environments
Publisher: Oxford University Press (OUP)
Date: 08-09-2020
Abstract: Helicobacter pylori is a fastidious Gram-negative bacterium that infects over half of the world's population, causing chronic gastritis and is a risk factor for stomach cancer. In developing and rural regions where prevalence rate exceeds 60%, persistence and waterborne transmission are often linked to poor sanitation conditions. Here we demonstrate that H. pylori not only survives but also replicates within acidified free-living amoebal phagosomes. Bacterial counts of the clinical isolate H. pylori G27 increased over 50-fold after three days in co-culture with amoebae. In contrast, a H. pylori mutant deficient in a cagPAI gene (cagE) showed little growth within amoebae, demonstrating the likely importance of a type IV secretion system in H. pylori for amoebal infection. We also demonstrate that H. pylori can be packaged by amoebae and released in extracellular vesicles. Furthermore, and for the first time, we successfully demonstrate the ability of two free-living amoebae to revert and recover viable but non-cultivable coccoid (VBNC)-H. pylori to a culturable state. Our studies provide evidence to support the hypothesis that amoebae and perhaps other free-living protozoa contribute to the replication and persistence of human-pathogenic H. pylori by providing a protected intracellular microenvironment for this pathogen to persist in natural aquatic environments and engineered water systems, thereby H. pylori potentially uses amoeba as a carrier and a vector of transmission.
Using faecal sterols from humans and animals to distinguish faecal pollution in receiving waters
Publisher: Elsevier BV
Date: 12-1996
Meeting Report: Knowledge and Gaps in Developing Microbial Criteria for Inland Recreational Waters
Publisher: Environmental Health Perspectives
Date: 06-2010
DOI: 10.1289/EHP.0901627
Editorial: Important news about this journal
Publisher: IWA Publishing
Date: 04-03-2021
DOI: 10.2166/WH.2021.000
Fate and transport of viruses during sewage treatment in a mound system
Publisher: Elsevier BV
Date: 06-2008
DOI: 10.1016/J.WATRES.2008.02.032
Abstract: Studies undertaken to assess the performance of filter materials to remove phosphorus in decentralised sewage systems have not reported on the broader performance of these systems. This study aimed to identify virus fate and transport mechanisms at the laboratory scale for comparison with field experiments on a mound system amended with blast furnace slag. Inactivation was a significant removal mechanism for MS2 bacteriophage, but not for PRD1 bacteriophage. Column studies identified rapid transport of PRD1. Laboratory studies predicted lower removal of PRD1 in a full scale system than was experienced in the field study, highlighting the importance of considering pH and flow rate in pathogen removal estimates. The results highlight the necessity for studying a range of organisms when assessing the potential for pathogen transport.
Evaluation of fluorochromes for flow cytometric detection of Cryptosporidium parvum oocysts labelled by fluorescent in situ hybridization
Publisher: Oxford University Press (OUP)
Date: 12-1998
DOI: 10.1046/J.1472-765X.1998.00446.X
Abstract: Oligonucleotide probes specific to Cryptosporidium parvum (CRY1) were conjugated with a range of fluorochromes. The fluorescence after in situ hybridization (FISH) labelling of oocysts and controls was assessed. The objective was to determine the most suitable conjugate for FISH labelling, followed by analysis with a 488 nm laser flow cytometer. The most promising candidate was fluorescein isothiocyanate but only when linked to the CRY1 probe via an 18-carbon spacer arm consisting of six ethylene glycol moieties. The use of the spacer increased fluorescent signals fivefold compared with an equivalent probe in which the FITC was linked directly to the 5'-amino group of the DNA.
Application of physico-chemical parameters and particle-bound biomarkers to indicate microbial contamination of aquifers
Publisher: IWA Publishing
Date: 12-2002
DOI: 10.2166/WS.2002.0199
Abstract: Reliance on coliform monitoring of ground waters is slowly changing as is reflected in the proposed US EPA Ground Water Rule. In line with this we have investigated the use of an expanded range of faecal indicators and potential surrogate analytes within the Gwelup and Jandakot borefields in Perth, Western Australia. The aims of the study included comparing contamination in bores and surface waters in vulnerable locations, quantifying aquifer removal of microorganisms, trialing novel biochemical pollution indicators such as faecal sterols, assessing Escherichia coli as a measure of groundwater contamination and generating data for risk assessments. S ling was undertaken of nine production bores, nine monitoring bores and four surface waters for 32 parameters comprising seven microbial indicators, 12 physico-chemical parameters and 13 biomarkers (including 8 faecal sterols and caffeine) at s ling stations potentially impacted by urban development. Concentrations of microbial indicators and biomarkers followed the pattern: basins & & monitoring bores & & production bores. Only one production bore s le contained bacterial indicators (0.1 enterococci.100 mL-1 on 1 occasion). Of the faecal biomarkers, coprostanol was generally at background levels. Cholesterol appeared to be a more sensitive measure of infiltration, but was also effectively removed. E. coli appeared to be a less sensitive indicator than enterococci. None of the physico-chemical parameters were useful surrogates. Overall apparent faecal microbial removal by aquifer filtration averaged & -5 logs (not accounting for viruses). To maximise warning time and assay sensitivity it is suggested that enterococci be considered as the key bacterial indicator rather than E. coli and that different combinations of indicators and biomarkers be used to identify aquifer locations at risk, the presence of significant faecal material, and the likely presence of pathogens.
Solar radiation disinfection of drinking water at temperate latitudes: Inactivation rates for an optimised reactor configuration
Publisher: Elsevier BV
Date: 02-2009
DOI: 10.1016/J.WATRES.2008.11.016
Abstract: Solar radiation-driven inactivation of bacteria, virus and protozoan pathogen models was quantified in simulated drinking water at a temperate latitude (34 degrees S). The water was seeded with Enterococcus faecalis, Clostridium sporogenes spores, and P22 bacteriophage, each at ca 1x10(5) mL(-1), and exposed to natural sunlight in 30-L reaction vessels. Water temperature ranged from 17 to 39 degrees C during the experiments lasting up to 6h. Dark controls showed little inactivation and so it was concluded that the inactivation observed was primarily driven by non-thermal processes. The optimised reactor design achieved S90 values (cumulative exposure required for 90% reduction) for the test microorganisms in the range 0.63-1.82 MJ m(-2) of Global Solar Exposure (GSX) without the need for TiO2 as a catalyst. High turbidity (840-920 NTU) only reduced the S(90) value by 0.05). However, inactivation was significantly reduced for E. faecalis and P22 when the transmittance of UV wavelengths was attenuated by water with high colour (140 PtCo units) or a suboptimally transparent reactor lid (prob.<0.05). S90 values were consistent with those measured by other researchers (ca 1-10 MJ m(-2)) for a range of waters and microorganisms. Although temperatures required for SODIS type pasteurization were not produced, non-thermal inactivation alone appeared to offer a viable means for reliably disinfecting low colour source waters by greater than 4 orders of magnitude on sunny days at 34 degrees S latitude.
The direct measurement of bacterial growth in biofilms of emergent plants (schoenoplectus) of an artificial wetland
Publisher: IWA Publishing
Date: 1995
Buffer distances for on-site sewage systems in Sydney's drinking water catchments
Publisher: IWA Publishing
Date: 04-2003
Abstract: Pathogens and nutrients released from on-site sewage systems represent a risk to surface and ground water quality, particularly where there are sensitive receiving waters such as in drinking water catchments. Buffer zones between on-site systems and waterways are one barrier used to protect water quality. The increased time and distance they provide increases the opportunities for the effluent purification functions of the soil to occur. A risk management model is proposed to assess the efficacy of the buffer zones in Sydney's drinking water catchments. The model is the basis for the development of performance based setback distances for on-site systems from waterways, and incorporates stochastic analysis of pathogen and nutrient transport in the environment and consideration of the effluent quality variability from on-site systems. Catchment-scale integration of contaminant transport is employed to facilitate a risk assessment of on-site systems. The risk management model also allows for the impact of on-site system management and maintenance on catchment water quality to be assessed through scenario building and feedback mechanisms.
Impacts of migratory Sandhill Cranes (Grus canadensis) on microbial water quality in the Central Platte River, Nebraska, USA
Publisher: Springer Science and Business Media LLC
Date: 21-05-2013
Evaluation of three full-scale stormwater treatment systems with respect to water yield, pathogen removal efficacy and human health risk from faecal pathogens
Publisher: Elsevier BV
Date: 02-2016
DOI: 10.1016/J.SCITOTENV.2015.11.056
Abstract: In this study, three full-scale, operational stormwater harvesting systems located in Melbourne, Australia were evaluated with respect to water yields pathogen removal performance by analysis of native surrogate data (Escherichiacoli, somatic coliphages and Clostridium perfringens) and potential human health risk associated with exposures to faecal pathogens using Quantitative Microbial Risk Assessment (QMRA). The water yield assessment confirmed variation between design and measured yields. Faecal contamination of urban stormwater was site specific and variable. Different treatment removal performance was observed between each of the microbial surrogates and varied between event and baseline conditions, with negligible removal of viruses during event conditions. Open storages that provide a habitat for waterfowl may lead to elevated risk due to the potential for zoonotic transmission. Nevertheless, in the Australian urban setting studied, the potential for human faecal contamination of the separated stormwater system was a critical driver of risk. If the integrity of the sewerage system can be ensured, then predicted health risks are dramatically reduced.
Your garden hose: A potential health risk due to Legionella spp. growth facilitated by free-living amoebae
Publisher: American Chemical Society (ACS)
Date: 19-08-2014
DOI: 10.1021/ES502652N
Abstract: Common garden hoses may generate aerosols of inhalable size (≤10 μm) during use. If humans inhale aerosols containing Legionella bacteria, Legionnaires' disease or Pontiac fever may result. Clinical cases of these illnesses have been linked to garden hose use. The hose environment is ideal for the growth and interaction of Legionella and free-living amoebae (FLA) due to biofilm formation, elevated temperatures, and stagnation of water. However, the microbial densities and hose conditions necessary to quantify the human health risks have not been reported. Here we present data on FLA and Legionella spp. detected in water and biofilm from two types of garden hoses over 18 months. By culturing and qPCR, two genera of FLA were introduced via the drinking water supply and reached mean densities of 2.5 log10 amoebae·mL(-1) in garden hose water. Legionella spp. densities (likely including pathogenic L. pneumophila) were significantly higher in one type of hose (3.8 log10 cells·mL(-1), p < 0.0001). A positive correlation existed between Vermamoebae vermiformis densities and Legionella spp. densities (r = 0.83, p < 0.028). The densities of Legionella spp. identified in the hoses were similar to those reported during legionellosis outbreaks in other situations. Therefore, we conclude that there is a health risk to susceptible users from the inhalation of garden hose aerosols.
Detection, integration and persistence of aeromonads in water distribution pipe biofilms
Publisher: IWA Publishing
Date: 06-2004
DOI: 10.2166/WH.2004.0008
Abstract: The occurrence of Aeromonas spp. within biofilms formed on stainless steel (SS), unplasticized polyvinyl chloride (uPVC) and glass (GL) substrata was investigated in modified Robbins Devices (MRD) in potable (MRD-p) and recycled (MRD-r) water systems, a Biofilm Reactor™ (BR) and a laboratory-scale pipe loop (PL) receiving simulated recycled wastewater. No aeromonads were isolated from the MRD-p whereas 3–10% of SS and uPVC coupons (mean 3.85 CFU cm−2 and 12.8 CFU cm−2, respectively) were aeromonad-positive in the MRD-r. Aeromonads were isolated from six SS coupons (67%) (mean 63.4 CFU cm−2) and nine uPVC coupons (100%) (mean 6.50×102 CFU cm−2) in the BR™ fed with recycled water and from all coupons (100%) in the simulated recycled water system (PL). Mean numbers of aeromonads on GL and SS coupons were 5.83×102 CFU cm−2 and 8.73×102 CFU cm−2, respectively. No isolate was of known human health significance (i.e. Aeromonas caviae, A. hydrophila or A. veronii), though they were confirmed as Aeromonas spp. by PCR and fluorescence in situ hybridization (FISH). Challenging the PL biofilms with a slug dose of A. hydrophila (ATCC 14715) showed that biofilm in the PL accumulated in the order of 103–104A. hydrophila cm−2, the number of which decreased over time, though could not be explained in terms of conventional 1st order decay kinetics. A sub-population of FISH-positive A. hydrophila became established within the biofilm, thereby demonstrating their ability to incorporate and persist in biofilms formed within distribution pipe systems. A similar observation was not made for culturable aeromonads, though the exact human health significance of this remains unknown. These findings, however, further question the adequacy of culture-based techniques and their often anomalous discrepancy with direct techniques for the enumeration of bacterial pathogens in environmental s les.
Capsid integrity qPCR -a propidium monoazide based and culture independent approach to estimate adenovirus infectivity after disinfection and in the aquatic environment of a rapidly developing region
Publisher: Unpublished
Date: 2019
Annual variations and effects of temperature on Legionella spp. and other potential opportunistic pathogens in a bathroom
Publisher: Springer Science and Business Media LLC
Date: 04-11-2017
Isolation of Legionella pneumophila by Co-culture with Local Ameba, Canada
Publisher: Centers for Disease Control and Prevention (CDC)
Date: 11-2019
Distribution and potential significance of a gull fecal marker in urban coastal and riverine areas of southern Ontario, Canada
Publisher: Elsevier BV
Date: 07-2011
DOI: 10.1016/J.WATRES.2011.05.003
Abstract: To better understand the distribution of gull fecal contamination in urban areas of southern Ontario, we used gull-specific PCR and qPCR assays against 1309 water s les collected from 15 urban coastal and riverine locations during 2007. Approximately, 58% of the water s les tested positive for the gull-assay. Locations observed to have higher numbers of gulls and their fecal droppings had a higher frequency of occurrence of the gull marker and a higher gull marker qPCR signal than areas observed to be less impacted by gulls. Lower gull marker occurrence and lower qPCR signals were associated with municipal wastewater (7.4%) and urban stormwater effluents (29.5%). Overall, there were no statistically significant differences in gull marker occurrence at beach sites for pore water, ankle, and chest-depth s les, although signals were generally higher in interstitial beach sand pore water and ankle-depth water than in chest-depth water s les. Overall, the results indicated that gull fecal pollution is widespread in urban coastal and riverine areas in southern Ontario and that it significantly contributes to fecal indicator bacterial loads.
A sea change ahead for recreational water quality criteria
Publisher: IWA Publishing
Date: 10-2008
DOI: 10.2166/WH.2009.122
Abstract: The United States Environmental Protection Agency is committed to developing new recreational water quality criteria for coastal waters by 2012 to provide increased protection to swimmers. We review the uncertainties and shortcomings of the current recreational water quality criteria, describe critical research needs for the development of new criteria, as well as recommend a path forward for new criteria development. We believe that among the most needed research needs are the completion of epidemiology studies in tropical waters and in waters adversely impacted by urban runoff and animal feces, as well as studies aimed to validate the use of models for indicator and pathogen concentration and health risk predictions.
Validating and optimizing the method for molecular detection and quantification of SARS-CoV-2 in wastewater
Publisher: Elsevier BV
Date: 03-2022
A Spike Cocktail Approach to Improve Microbial Performance Monitoring for Water Reuse
Publisher: Wiley
Date: 09-2016
Molecular Detection of Campylobacter spp. and Fecal Indicator Bacteria during the Northern Migration of Sandhill Cranes (Grus canadensis) at the Central Platte River
Publisher: American Society for Microbiology
Date: 15-06-2013
DOI: 10.1128/AEM.03990-12
Abstract: The risk to human health of the annual sandhill crane ( Grus canadensis ) migration through Nebraska, which is thought to be a major source of fecal pollution of the central Platte River, is unknown. To better understand potential risks, the presence of C ylobacter species and three fecal indicator bacterial groups ( Enterococcus spp., Escherichia coli , and Bacteroidetes ) was assayed by PCR from crane excreta and water s les collected during their stopover at the Platte River, Nebraska, in 2010. Genus-specific PCR assays and sequence analyses identified C ylobacter jejuni as the predominant C ylobacter species in sandhill crane excreta. C ylobacter spp. were detected in 48% of crane excreta, 24% of water s les, and 11% of sediment s les. The estimated densities of Enterococcus spp. were highest in excreta s les (mean, 4.6 � 10 8 cell equivalents [CE]/g), while water s les contained higher levels of Bacteroidetes (mean, 5.1 � 10 5 CE/100 ml). Enterococcus spp., E. coli , and C ylobacter spp. were significantly increased in river water and sediments during the crane migration period, with Enterococcus sp. densities (∼3.3 � 10 5 CE/g) 2 to 4 orders of magnitude higher than those of Bacteroidetes (4.9 � 10 3 CE/g), E. coli (2.2 � 10 3 CE/g), and C ylobacter spp. (37 CE/g). Sequencing data for the 16S rRNA gene and C ylobacter species-specific PCR assays indicated that C. jejuni was the major C ylobacter species present in water, sediments, and crane excreta. Overall, migration appeared to result in a significant, but temporary, change in water quality in spring, when there may be a C. jejuni health hazard associated with water and crops visited by the migrating birds.
Wastewater-Based Surveillance Is an Effective Tool for Trending COVID-19 Prevalence in Communities: A Study of 10 Major Communities for 17 Months in Alberta
Publisher: American Chemical Society (ACS)
Date: 19-09-2022
A one-step centrifugal ultrafiltration method to concentrate enteric viruses from wastewater
Publisher: Elsevier BV
Date: 11-2016
DOI: 10.1016/J.JVIROMET.2016.09.010
Abstract: A one-step centrifugal ultrafiltration method was developed to enhance rapid detection of human enteric viruses and co-occurring viruses in wastewater. S les were collected pre- and post-UV treatment at two full-scale tertiary municipal wastewater treatment plants in Calgary, Canada. Viruses were concentrated from 100mL wastewater s les through direct centrifugation using the Centricon Plus-70 ultrafilter. Seven viruses, including norovirus, rotavirus, sapovirus, astrovirus, enterovirus, adenovirus and JC virus, were tested using real-time quantitative PCR (rt-qPCR) and cell culture. All of the viruses were detected in pre- and post-UV s les by rt-qPCR, with rotavirus the most numerous (6.6 log
Number of COVID-19 cases required in a population to detect SARS-CoV-2 RNA in wastewater in the province of Alberta, Canada: Sensitivity assessment
Publisher: Elsevier BV
Date: 03-2023
Global Warming and Trans-Boundary Movement of Waterborne Microbial Pathogens
Publisher: Springer Japan
Date: 2010
The value of floc and biofilm bacteria for anammox stability when treating ammonia-rich digester sludge thickening lagoon supernatant
Publisher: Elsevier BV
Date: 10-2019
DOI: 10.1016/J.CHEMOSPHERE.2019.05.287
Abstract: Ammonia-rich lagoon supernatant was treated using anammox process in an integrated fixed-film activated sludge (IFAS) laboratory reactor. Effective anammox activities were demonstrated over 259 days of operation. The ammonium removal efficiency reached 94% in Phase I with influent concentrations of NH
Interactions between Human Reovirus and Free-Living Amoebae: Implications for Enteric Virus Disinfection and Aquatic Persistence
Publisher: American Chemical Society (ACS)
Date: 09-07-2020
Viability of a Single-Stage Unsaturated-Saturated Granular Activated Carbon Biofilter for Greywater Treatment
Publisher: MDPI AG
Date: 24-10-2020
DOI: 10.3390/SU12218847
Abstract: Compared with conventionally collected sewage, source- erted greywater has a higher potential for on-site treatment and reuse due to its lower contaminant levels and large volume. A new design of granular activated carbon (GAC) biofilters was developed by incorporating unsaturated and saturated zones in a single stage to introduce an efficient, passive, and easy-to-operate technology for greywater on-site treatment at the household scale. The design was customized for its intended application considering various aspects including the reactor’s configuration, packing media, and feeding strategy. With the highest hydraulic and organic loadings of 1.2 m3 m−2 d−1 and 3.5 kg COD m−2 d−1, respectively, and the shortest retention time of 2.4 h, the system maintained an average total chemical oxygen demand removal rate of 94% with almost complete removal of nutrients throughout its 253 days of operation. The system showed a range of reduction efficacy towards five surrogates representing viruses, bacteria, and Cryptosporidium and Giardia (oo)cysts. A well-functioning biofilm was successfully developed, and its mass and activity increased over time with the highest values observed at the top layers. The key microbes within the biofilter were revealed. Feasibility of the proposed technology was investigated, and implications for design and operation were discussed.
Microbial risk assessment of source-separated urine used in agriculture
Publisher: SAGE Publications
Date: 04-2002
DOI: 10.1177/0734242X0202000207
Abstract: A screening-level quantitative microbial risk assessment (QMRA) was undertaken for a urine separating sewer-age system. Exposures evaluated included the handling of stored and unstored urine as well as consumption of crops fertilised with urine. Faecal cross-contamination was the source of risk and C ylobacter jejuni, Cryptosporidium parvum and rotavirus were the organisms chosen to represent different groups of enteric pathogens. Accidental ingestion of unstored urine implied a high risk (P inf = 0.56) for infection from rotavirus whereas the risks for infection from bacteria and protozoa were approximately 1:10 000. After six months storage at 20°C the risk for viral infections by accidental ingestion of 1 ml of urine was -3 , the suggested acceptable risk benchmark. Ingestion of crops contaminated with urine resulted in risks of -5 after a 3-week ( -7 after 4 weeks) withholding period between fertilising and harvesting.
Decentralised urban water reuse; the implications of system scale for cost and pathogen risk
Publisher: IWA Publishing
Date: 09-2002
Abstract: The non-potable reuse of treated sewage in urban areas provides significant conservation of potable supplies beyond that available through water use efficiency. Effluent reuse is also an inevitable requirement in novel decentralised wastewater systems. At present, urban water reuse, where pursued, usually involves large-scale schemes based on new or existing centralised sewage treatment plants. This is despite the diseconomy of scale inherent in pipe networks that balances economies of scale in sewage treatment and negates any cost advantage for wastewater systems with more than around 1,000 connections. In light of this, the theoretical relationship between effluent reuse system scale and pathogen risks was examined at various effluent qualities. Waterborne disease was seen to be a significant factor when reusing effluent in urban areas and smaller systems were found to pose a lower risk of waterborne infection, all other things being equal. Pathogen risks were then included within an economic analysis of system scale. It was concluded that with the inclusion of pathogen risks as a costed externality, taking a decentralised approach to urban water reuse would be economically advantageous in most cases. This conclusion holds despite an exact evaluation of increased waterborne disease due to effluent reuse remaining problematic.
Global and local health burden trade-off through the hybridisation of quantitative microbial risk assessment and life cycle assessment to aid water management
Publisher: Elsevier BV
Date: 08-2015
DOI: 10.1016/J.WATRES.2015.03.015
Abstract: Life cycle assessment (LCA) and quantitative risk assessment (QRA) are commonly used to evaluate potential human health impacts associated with proposed or existing infrastructure and products. Each approach has a distinct objective and, consequently, their conclusions may be inconsistent or contradictory. It is proposed that the integration of elements of QRA and LCA may provide a more holistic approach to health impact assessment. Here we examine the possibility of merging LCA assessed human health impacts with quantitative microbial risk assessment (QMRA) for waterborne pathogen impacts, expressed with the common health metric, disability adjusted life years (DALYs). The ex le of a recent large-scale water recycling project in Sydney, Australia was used to identify and demonstrate the potential advantages and current limitations of this approach. A comparative analysis of two scenarios - with and without the development of this project - was undertaken for this purpose. LCA and QMRA were carried out independently for the two scenarios to compare human health impacts, as measured by DALYs lost per year. LCA results suggested that construction of the project would lead to an increased number of DALYs lost per year, while estimated disease burden resulting from microbial exposures indicated that it would result in the loss of fewer DALYs per year than the alternative scenario. By merging the results of the LCA and QMRA, we demonstrate the advantages in providing a more comprehensive assessment of human disease burden for the two scenarios, in particular, the importance of considering the results of both LCA and QRA in a comparative assessment of decision alternatives to avoid problem shifting. The application of DALYs as a common measure between the two approaches was found to be useful for this purpose.
Incorporating method recovery uncertainties in stochastic estimates of raw water protozoan concentrations for QMRA
Publisher: IWA Publishing
Date: 09-2007
DOI: 10.2166/WH.2006.047
Abstract: In response to Hurricane Mitch, which struck Central America in October–November 1998, the American Red Cross (ARC) and the Centers for Disease Control and Prevention (CDC) collaborated on a 3-year evaluation of the public health impact of ARC's water, sanitation and hygiene education activities in eight study areas in Honduras, Nicaragua, El Salvador and Guatemala. The evaluation compared: 1) access to and use of water and sanitation facilities, 2) the use of hygienic behaviours, and 3) diarrhoeal prevalence in children younger than 3 years of age before (February 2000) and after (February 2002) the interventions had been implemented. The evaluation included household and key informant interviews designed to measure these three components. Water quality of community water sources and household water was evaluated by measuring levels of indicator bacteria. During the final survey, an infrastructure evaluation provided a review of the design, construction, and current operation and maintenance of the water systems and latrines. The integrated water and sanitation infrastructure interventions and hygiene education programmes implemented following Hurricane Mitch effectively decreased diarrhoea prevalence in the target communities.
Critical insights for a sustainability framework to address integrated community water services: Technical metrics and approaches
Publisher: Elsevier BV
Date: 06-2015
DOI: 10.1016/J.WATRES.2015.03.017
Abstract: Planning for sustainable community water systems requires a comprehensive understanding and assessment of the integrated source-drinking-wastewater systems over their life-cycles. Although traditional life cycle assessment and similar tools (e.g. footprints and emergy) have been applied to elements of these water services (i.e. water resources, drinking water, stormwater or wastewater treatment alone), we argue for the importance of developing and combining the system-based tools and metrics in order to holistically evaluate the complete water service system based on the concept of integrated resource management. We analyzed the strengths and weaknesses of key system-based tools and metrics, and discuss future directions to identify more sustainable municipal water services. Such efforts may include the need for novel metrics that address system adaptability to future changes and infrastructure robustness. Caution is also necessary when coupling fundamentally different tools so to avoid misunderstanding and consequently misleading decision-making.
SIGNIFICANCE OF SPECIFIC BACTERIAL PATHOGENS IN THE ASSESSMENT OF POLLUTED RECEIVING WATERS OF SYDNEY, AUSTRALIA
Publisher: IWA Publishing
Date: 02-1993
Abstract: The impact of primary sewage released from Sydney's ocean outfalls and chlorinated tertiary treated sewage effluent discharged into Sydney's main river system (Hawkesbury-Nepean) have been studied for faecal microorganisms over two years. Faecal indicator bacteria and a range of potential bacterial pathogens (Aeromonas spp., C ylobacters, Pseudomonas aeruginosa, Staphylococcus aureus and salmonellae) were also cultured. Diverting primary-treated sewage from cliff edge release to deepwater (80m) ocean release some 3 km offshore resulted in significant reductions in all bacterial groups examined, with spores of Clostridium perfringens (C.p) being the most sensitive indicator of water quality improvement. In contrast, contamination of inshore sediments has not markedly declined. C ylobacters were not isolated from effluents or seawater, and numbers of S. aureus and P. aeruginosa were very low if detected. Inland river waters were dominated by motile aeromonads, and along with C.p were the most resistant organisms to chlorination following tertiary sewage treatment. However, aeromonads appeared to grow throughout the river system. C ylobacters were associated with areas of agricultural input whereas salmonellae appeared to be associated with significant urban sewage input. Of the indicator bacteria, C.p correlated best with salmonellae, while viruses correlated poorly with the bacterial groups examined. Further work is required to identify possible sources of virulent aeromonads, C ylobacters and salmonellae.
Photovoltaic powered ultraviolet and visible light-emitting diodes for sustainable point-of-use disinfection of drinking waters
Publisher: Elsevier BV
Date: 09-2014
DOI: 10.1016/J.SCITOTENV.2014.05.104
Abstract: For many decades, populations in rural and remote developing regions will be unable to access centralised piped potable water supplies, and indeed, decentralised options may be more sustainable. Accordingly, improved household point-of-use (POU) disinfection technologies are urgently needed. Compared to alternatives, ultraviolet (UV) light disinfection is very attractive because of its efficacy against all pathogen groups and minimal operational consumables. Though mercury arc l technology is very efficient, it requires frequent l replacement, involves a toxic heavy metal, and their quartz envelopes and sleeves are expensive, fragile and require regular cleaning. An emerging alternative is semiconductor-based units where UV light emitting diodes (UV-LEDs) are powered by photovoltaics (PV). Our review charts the development of these two technologies, their current status, and challenges to their integration and POU application. It explores the themes of UV-C-LEDs, non-UV-C LED technology (e.g. UV-A, visible light, Advanced Oxidation), PV power supplies, PV/LED integration and POU suitability. While UV-C LED technology should mature in the next 10 years, research is also needed to address other unresolved barriers to in situ application as well as emerging research opportunities especially UV-A, photocatalyst hotosensitiser use and pulsed emission options.
Molecular survey of occurrence and quantity of Legionella spp., Mycobacterium spp., Pseudomonas aeruginosa and amoeba hosts in municipal drinking water storage tank sediments
Publisher: Oxford University Press (OUP)
Date: 05-06-2015
DOI: 10.1111/JAM.12831
Abstract: To examine the occurrence and quantity of potential pathogens and an indicator of microbial contamination in the sediments of municipal drinking water storage tanks (MDWSTs), given the absence of such data across the United States. Sediment s les (87 MDWST) from eighteen locations across ten states of the United States were collected and assayed by qPCR for a range of potential enteric and opportunistic microbial pathogens and a sewage-associated Bacteroides marker. Potential opportunistic pathogens dominated, with the highest detection of occurrence (per cent positive detection average cell equivalence (CE)) being Mycobacterium spp. (88·9% 6·7 ± 8·5 × 10(4) CE g(-1) ), followed by Legionella spp. (66·7% 5·2 ± 5·9 × 10(3) CE g(-1) ), Pseudomonas aeruginosa (22·2% 250 ± 880 CE g(-1) ) and Acanthamoeba spp. (38·9% 53 ± 70 CE g(-1) ), with no detected Naegleria fowleri. Most enteric pathogens (C ylobacter jejuni, Escherichia coli 0157:H7, Salmonella enterica, Cryptosporidium parvum and Giardia duodenalis) were not detected, except for a trace signal for C ylobacter spp. There was significant correlation between the qPCR signals of Legionella spp. and Acanthamoeba spp. (R(2) = 0·61, n = 87, P = 0·0001). Diverse Legionella spp. including Leg. pneumophila, Leg. pneumophila sg1 and Leg. anisa were identified, each of which might cause legionellosis. These results imply that potential opportunistic pathogens are common within MDWST sediments and could act as a source of microbial contamination, but need downstream growth to be of potential concern. The results imply that opportunistic pathogen risks may need to be managed by regular tank cleaning or other management practices.
Hartmannella vermiformis Inhibition of Legionella pneumophila Cultivability
Publisher: Springer Science and Business Media LLC
Date: 14-06-2013
DOI: 10.1007/S00248-013-0250-Z
Abstract: Hartmannella vermiformis and Acanthamoeba polyphaga are frequently isolated from drinking water and permissive to Legionella pneumophila parasitization. In this study, extracellular factor(s) produced by H. vermiformis and A. polyphaga were assessed for their effects on cultivability of L. pneumophila. Page's amoeba saline (PAS) was used as an encystment medium for H. vermiformis and A. polyphaga monolayers, and the culture supernatants (HvS and ApS, respectively) were assessed against L. pneumophila growth. Compared to PAS and ApS, HvS significantly inhibited L. pneumophila strain Philadelphia-1 (Ph-1) cultivability by 3 log(10) colony forming unit (CFU) mL(-1) after 3 days of exposure compared to <0.5 log(10) CFU mL(-1) reduction of strain Lp02 (P < 0.001). Flow cytometric analysis revealed changes in the percentage and cultivability of three bacterial subpopulations: intact/slightly damaged membrane (ISM), undefined membrane status (UD), and mixed type (MT). After 3 days of HvS exposure, the MT subpopulation decreased significantly (31.6 vs 67.2 %, respectively, P < 0.001), while the ISM and UD subpopulations increased (+26.7 and +6.9 %, respectively) with the ISM subpopulation appearing as viable but nonculturable (VBNC) cells. HvS was separated into two fractions based on molecular weight, with more than 99 % of the L. pneumophila inhibition arising from the <5 kDa fraction (P < 0.001). Liquid chromatography indicated the inhibitory molecule(s) are likely polar and elute from a Novapak C18 column between 6 and 15 min. These results demonstrate that H. vermiformis is capable of extracellular modulation of L. pneumophila cultivability and probably promote the VBNC state for this bacterium.
Field scale quantification of microbial transport from bovine faeces under simulated rainfall events
Publisher: IWA Publishing
Date: 09-2006
DOI: 10.2166/WH.2006.050
Abstract: The dispersion and transport of Cryptosporidium parvum oocysts, Escherichia coli and PRD1 bacteriophage seeded into artificial bovine faecal pats was studied during simulated rainfall events. Experimental soil plots were ided in two, one sub-plot with bare soil and the other with natural vegetation. Simulated rainfall events of 55 mm.h-1 for 30 min were then applied to the soil plots. Each experimental treatment was performed in duplicate and consisted of three sequential artificial rainfall events (‘Runs’): a control run (no faecal pats) a fresh faecal pat run (fresh faecal pats) and an aged faecal pat run (one week aged faecal pats). Transportation efficiency increased with decreasing size of the microorganism studied Cryptosporidium oocysts were the least mobile followed by E. coli and then PRD1 phage. Rainfall events mobilised 0.5 to 0.9% of the Cryptosporidium oocysts, 1.3‒1.4% of E. coli bacteria, and 0.03‒0.6% of PRD1 bacteriophages from the fresh faecal pats and transported them a distance of 10 m across the bare soil sub-plots. Subsequent rainfall events applied to aged faecal pats only mobilised 0.01‒0.06% of the original Cryptosporidium oocyst load, between 0.04 and 15% of the E. coli load and 0.0006‒0.06% of PRD1 bacteriophages, respectively.
The identification and human health significance of environmental Aeromonads
Publisher: IWA Publishing
Date: 1995
Estimating the risk from sewage treatment plant effluent in the Sydney catchment area
Publisher: IWA Publishing
Date: 04-2011
DOI: 10.2166/WST.2011.408
Abstract: This study employed Quantitative Microbial Risk Assessment (QMRA) to estimate the gastrointestinal risks associated with Cryptosporidium and Giardia discharged from three STPs located within the Lake Burragorang catchment. The QMRA considered baseline and various hazardous event scenarios (e.g. plant failure and heavy rainfall). Under baseline conditions, the combined effect of constructed barriers, catchment barriers and dilution reduced pathogen numbers from the discharge of all three STPs by 10 to 14 orders of magnitude. This was sufficient for the risk to be well below currently mooted benchmarks of ‘tolerable risk’, even when relatively conservative assumptions were applied. For all hazardous event scenarios, the level of risk remained low, which illustrated the benefit of multiple barriers. Provisionally it appears that the STPs currently discharging into the waterways of the catchment do not pose an unacceptable or unmanageable risk to Sydney's drinking water consumers.
DETECTION OF VIRUSES IN COASTAL AND RIVER WATER-SYSTEMS IN SYDNEY, AUSTRALIA
Publisher: IWA Publishing
Date: 02-1993
Abstract: Two prospective studies on the occurrence of human viruses in s les of coastal & river origin have been undertaken since September 1989. Viruses were detected using concentration methods & cell culture techniques. Water s les (100L) were reduced to 1L using hollow fibre ultrafiltration and then treated with PEG. Sewage and sediment s les were treated with PEG only. Over a two year period, viruses were detected in 24/202 (12%) of water s les and 29/60 effluents from the river system. Coastal waters have been contaminated by cliff edge discharge of sewage for at least the last 70 years. Recently, deepwater ocean outfalls have been installed to discharge effluent some 3 km away from the coast. Prior to the installation of deepwater ocean outfalls viruses were detected in 28% of water s les compared to 9% post installation. In sediment s les viruses were isolated in 87/260 (34%) s les, the discharge via the new outfalls having no effect on the isolation rate. The data points to long term survival of viruses sediments and/or contamination from other sources such as storm water discharge: 10-25% of storm water drains were also found to be positive for viruses. The viruses isolated were enteroviruses, adenoviruses & reoviruses. Although viruses were consistently isolated with some seasonal trends, comparisons between the detection of viruses in clinical and environmental s les over this two year period were inconclusive.
Innovative production treatment hydroponic farm for primary municipal sewage utilisation
Publisher: Elsevier BV
Date: 15-02-2000
Searching for Activity Markers that Approximate (VBNC) Legionella pneumophila Infectivity in Amoeba after Ultraviolet (UV) Irradiation
Publisher: MDPI AG
Date: 10-09-2018
DOI: 10.3390/W10091219
Abstract: Legionella pneumophila is an increasingly recognized threat to public health via aerosol exposures with a variety of control measures including: water temperature/flow management and free chlorine used to reduce the risk of infection within healthcare centers. Despite these efforts, L. pneumophila often recolonizes plumbing systems after specific treatments, which prompted us to examine ultraviolet (UV) irradiation for a point-of-use, secondary control measure. Currently, there is no data on the efficacy of high ( nm) wavelength UV-C (100–280 nm) light inactivation of L. pneumophila with resuscitation of viable but non-culturable (VBNC) cells. We report for the first time L. pneumophila dose-responses for 268.6 nm and 288.6 nm UV-C, as compared to 256 nm, and demonstrate UV induced VBNC L. pneumophila remaining infectious to Acanthamoeba polyphaga during co-culture experiments. Findings were correlated to molecular-based activity assays to identify additional measures of L. pneumophila viability following UV disinfection compared to culture. A collection of viability markers may provide a more representative measure of risk compared to current culture-based detection, since UV-C irradiated L. pneumophila lose culturability, yet retain activity, increased ATP production, and the ability to be resuscitated by amoeba co-culture. This finding is significant as it identifies potential concern from VBNC cells following UV-C disinfection and the need for further research into the efficacy of UV inactivation as a point-of-use application for L. pneumophila control and management.
The effects of UV disinfection on distribution pipe biofilm growth and pathogen incidence within the greater Stockholm area, Sweden
Publisher: Elsevier BV
Date: 08-2007
DOI: 10.1016/J.WATRES.2007.04.024
Abstract: An assessment of the effects of the transition from conventional chlorination to UV disinfection on potable water biofilm growth and pathogen incidence was made. Two hydraulic systems were tested, one a 1.0 km polyethylene pilot-scale system within the Lovö waterworks, Stockholm, Sweden, as well as Hässelby and Nockeby municipal distribution systems within the greater Stockholm area. Biofilms were propagated on coupons and the amount of biomass analysed by standard culture and molecular methods. There was no measurable difference in biofilm biomass or pathogen incidence in the transition from conventional chlorination to UV-treatment in any system examined. With the exception of aeromonads, frank (salmonellae, enterobacteria) and opportunistic (legionellae) pathogens as well as indicator bacteria (E. coli, coliforms, enterococci) could not be detected within biofilms in either the pilot-scale or large-scale municipal system. Free-living protozoa were detected almost ubiquitously in biofilm s les in either experimental system though their exact significance and impact remains unknown and warrants further investigation.
Fed-batch fermentation for production of Kluyveromyces marxianusFII 510700 cultivated on a lactose-based medium
Publisher: Oxford University Press (OUP)
Date: 16-06-2005
DOI: 10.1007/S10295-005-0245-Y
Abstract: A strain of Kluyveromyces marxianus was grown in batch culture in lactose-based media at varying initial lactose concentrations (10-60 g L(-1)) at 30 degrees C, pH 5.0, dissolved oxygen concentrations greater than 20%. Increasing the concentration of mineral salts three-fold at 40 g L(-1) and 60 g L(-1) initial lactose concentration showed only a small increase in the yield of biomass, from 0.38 g g(-1) to 0.41 g g(-1), indicating that the initial batch cultures were not significantly nutrient- (mineral salts)-limited. A relatively high biomass concentration (105 g L(-1)) was obtained in fed-batch culture following extended lactose feeding. An average specific growth rate (0.27 h(-1)), biomass yield (0.38 g g(-1)) and overall productivity (2.9 g L(-1) h(-1)) were obtained for these fed-batch conditions. This fed-batch protocol provides a strategy for achieving relatively high concentrations and productivities of K. marxianus on other lactose-based substrate streams (e.g., whey) from the dairy industry.
Microbial risks from wastewater irrigation of salad crops: A screening-level risk assessment
Publisher: Wiley
Date: 11-2002
Abstract: The potential health risk from viruses, associated with the consumption of lettuce crops spray irrigated with secondary-treated municipal effluent, has been evaluated in the first level investigation of a tiered microbial risk assessment. The study assessed the impact of two factors on the estimated risk of infection: a suitable probability density function for the occurrence of human enteroviruses in irrigation water and appropriate die-off rates for viruses on lettuce crops. A Monte Carlo simulation using a log-normal and a nonparametric, kernel estimated probability density function indicated that slight changes in the upper tail of the probability density function had a relatively low effect on the estimated infection rates. Predicted infection rates were much more sensitive to the decay rate of viruses than occasional high virus numbers. The median and 99th percentile risks of infection from the overall model were 0.10 and 0.51/10000 lettuce consumers, respectively, indicating possible human health concern, and the justification of a more detailed microbial risk assessment.
Influence of music on driver psychology and safety-relevant behaviours: a multi-study inductive content analysis
Publisher: Informa UK Limited
Date: 13-12-2021
QMRA and water safety management: Review of application in drinking water systems
Publisher: IWA Publishing
Date: 05-04-2016
DOI: 10.2166/WH.2016.262
Abstract: Quantitative microbial risk assessment (QMRA), the assessment of microbial risks when model inputs and estimated health impacts are explicitly quantified, is a valuable tool to support water safety plans (WSP). In this paper, research studies undertaken on the application of QMRA in drinking water systems were reviewed, highlighting their relevance for WSP. The important elements for practical implementation include: the data requirements to achieve sufficient certainty to support decision-making level of expertise necessary to undertake the required analysis and the accessibility of tools to support wider implementation, hence these aspects were the focus of the review. Recommendations to support the continued and growing application of QMRA to support risk management in the water sector are provided.
Development of a planning framework for sustainable rural water supply and sanitation: A case study of a filipino NGO
Publisher: Informa UK Limited
Date: 2010
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