ORCID Profile
0000-0001-9190-8812
Current Organisation
Murdoch University
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Publisher: IWA Publishing
Date: 06-1997
Abstract: Stabilised wastewater sludge (biosolids) has beneficial re-use properties but these are limited by the presence of human pathogens. In this study soil amendment with biosolids and storage of biosolids prior to re-use were examined as disposal and treatment options. In a soil amendment trial biosolids were mixed with sandy soil and monitored for 37 weeks. In two storage trials biosolids were stored in piles 1m high and monitored for & weeks. Included in the monitoring programme were tests to determine the concentrations of faecal coliforms, faecal streptococci and salmonellae. In both the soil amendment trials and biosolids storage trials, concentrations of indicator organisms and salmonellae decreased through an extended hot, dry summer period. Although these organisms were not detected in the majority of s les taken during the summer, repopulation of faecal coliforms and salmonellae occurred in the trials following rainfall at the beginning of the winter. In the case of one of the storage trials repopulation occurred following a period of 50 weeks when salmonellae and faecal coliforms were not detected. When repopulation occurred, faecal coliform concentrations increased to higher than those at the beginning of the trials. These results suggest that faecal coliforms and salmonellae were at undetectable concentrations through the summer period but were able to grow when provided with favourable conditions. From this limited trial it was concluded that soil amended with biosolids could not be considered free from pathogens for at least one year following amendment.
Publisher: IWA Publishing
Date: 1991
Abstract: Column experiments were conducted to determine the improvement in the removal of Escherichia coli, Salmonella adelaide and poliovirus-1 through sands by amendment with bauxite refining residue. The residue (red mud) was neutralized using 5 % gypsum and incorporated to form 30% of the amended sands. In 65 cm long soil columns the removal of the three organisms in the amended sand columns was excellent with over seven orders of magnitude reduction in concentration. Removal in unamended sands was poor. From breakthrough curves in unamended sand columns filtration, die-off and adsorption all appear to play a role in organism removal. The results also show that E. coli can be used as an indicator for contamination, though S.adelaide was less efficiently removed than E. coli. Poliovirus was on the other hand better removed than E. coli.
Publisher: Elsevier BV
Date: 03-2014
Publisher: Elsevier BV
Date: 08-1994
Publisher: IWA Publishing
Date: 21-10-2014
Abstract: The methodologies of demand-led sanitation programmes (including community-led total sanitation [CLTS] and sanitation marketing) encourage participation of users in the design of appropriate sanitation facilities. There has been limited examination of the application of established methodologies in participatory design in the sanitation sector. This paper describes and reflects upon three case studies that applied established participatory design methodologies to create sanitation technologies in rural Malawi. Participants of the design sessions represented two groups: (i) researcher–designers (government staff) and (ii) users (local builders and householders). The methodology created a space to develop a common language between the two groups and allowed an exploration of tensions about the use of sanitation hardware subsidies. The design sessions created a number of innovations including corbelling structures, trapezium shaped bricks and reinforcement of wooden frame structures with sandbags. The paper critically reflects on the processes of participatory design in relation to power, ownership and continued participation.
Publisher: Elsevier BV
Date: 07-2018
Publisher: Elsevier BV
Date: 09-2011
DOI: 10.1016/J.BIORTECH.2011.06.008
Abstract: This study aims to determine suitable start-up conditions and inoculum sources for thermophilic anaerobic digestion. Within days of incubation MSW at 55°C, methane was produced at a high rate. In an attempt to narrow down which components of typical MSW contained the thermophilic methanogens, vacuum cleaner dust, banana peel, kitchen waste, and garden waste were tested as inoculum for thermophilic methanogenesis with acetate as the substrate. Results singled out grass turf as the key source of thermophilic acetate degrading methanogenic consortia. Within 4 days of anaerobic incubation (55°C), anaerobically incubated grass turf s les produced methane accompanied by acetate degradation enabling successful start-up of thermophilic anaerobic digestion. Other essential start-up conditions are specified. Stirring of the culture was not conducive for successful start-up as it resulted specifically in propionate accumulation.
Publisher: Elsevier BV
Date: 10-2018
DOI: 10.1016/J.JENVMAN.2018.05.088
Abstract: Biofouling in seawater reverse osmosis (SWRO) membranes is a critical issue faced by the desalination industry worldwide. The major cause of biofouling is the irreversible attachment of recalcitrant biofilms formed by bacteria and their extracellular polymeric substances (EPS) on membrane surfaces. Transparent exopolymer particles (TEP) and protobiofilms are recently identified as important precursors of membrane fouling. Despite considerable amount of research on SWRO biofouling, the control of biofouling still remains a challenge. While adoption of better pretreatment methods may help in preventing membrane biofouling in new desalination setups, it is also crucial to effectively disperse old, recalcitrant biofilms and prolong membrane life in operational plants. Most current practices employ the use of broad spectrum biocides and chemicals that target bacterial cells to disperse mature biofilms, which are evidently inefficient. EPS, being known as the strongest structural framework of biofilms, it is essential to breakdown and disintegrate the EPS components for effective biofilm removal. To achieve this, it is necessary to understand the chemical composition and key elements that constitute the EPS of major biofouling bacterial groups in multi-species, mature biofilms. However, significant gaps in understanding the complexity of EPS are evident by the failure to achieve effective prevention and mitigation of fouling in most cases. Some of the reasons may be difficulty in s ling membranes from fully operational full-scale plants, poor understanding of microbial communities and their ecological shifts under dynamic operational conditions within the desalination process, selection of inappropriate model species for laboratory-scale biofouling studies, and the laborious process of extraction and purification of EPS. This article reviews the novel findings on key aspects of SWRO membrane fouling and control measures with particular emphasis on the key sugars in EPS. As a novel strategy to alleviate biofouling, future control methods may be aimed towards specifically disintegrating and breaking down these key sugars rather than using broad spectrum chemicals such as biocides that are currently used in the industry.
Publisher: Elsevier BV
Date: 03-1982
Publisher: Elsevier BV
Date: 02-2018
Publisher: Springer Science and Business Media LLC
Date: 2002
Publisher: IWA Publishing
Date: 05-2005
Abstract: An alternative method to conserve water and produce crops in arid regions is through hydroponics. Application of treated wastewater for hydroponics will help in stripping off nutrients from wastewater, maximising reuse through reduced evaporation losses, increasing control on quality of water and reducing risk of pathogen contamination. This study focuses on the efficiency of treated wastewater from an on-site aerobic wastewater treatment unit. The experiment aimed to investigate 1) nutrient reduction 2) microbial reduction and 3) growth rate of plants fed on wastewater compared to a commercial hydroponics medium. The study revealed that the chemical and microbial quality of wastewater after hydroponics was safe and satisfactory for irrigation and plant growth rate in wastewater hydroponics was similar to those grown in a commercial medium.
Publisher: IWA Publishing
Date: 1996
Publisher: IWA Publishing
Date: 11-1992
Abstract: Struvite (MgNH4PO4·6H2O) solution chemistry was studied in order to understand a struvite scaling problem which exists in the pipe network of a series of 4 effluent lagoons at a piggery. The conditional solubility constant (PS=SMG·SNH3−N·SPO4−P, equilibrium S values (M)) was determined over a range of pH values (6.8-8.5) and solution concentrations of Mg, NH3−N and PO4−P close to field conditions, and at a temperature of 30°C. A comparison of field and laboratory data indicates struvite precipitates from the second lagoon onwards. The solubility data obtained also indicate potential for precipitation as a method of nutrient removal from wastewaters.
Publisher: MDPI AG
Date: 17-08-2020
DOI: 10.3390/W12082310
Abstract: There is paucity of data on the quantification of the benefits of residential greywater reuse via direct ersion. While estimates have been made based on modelling the potential mains water savings, it is also recognised that the practicalities of system operation and occupant behaviour introduce substantial variation to these estimates. Three single residential housing projects in Fremantle, Western Australia, undertaken over ten years with a substantial focus on water efficiency and mains water substitution, have provided an opportunity to quantify these benefits. All three dwellings were intensively metered and documented. This paper describes the learnings generated along the way, including the methodology developed to effectively integrate direct ersion greywater reuse into a productive garden, along with other water sources to satisfy landscape water demand. Importantly a robust quantification of actual greywater volumes and associated mains water savings was made. The publication of actual greywater volumes will significantly contribute to this field and go a long way towards validating the merits of residential greywater reuse on mains water savings when systems are properly installed and operated. Brief considerations are also provided for energy efficiency and financial assessment.
Publisher: Elsevier BV
Date: 12-2012
DOI: 10.1016/J.BIORTECH.2012.08.091
Abstract: Sodium toxicity is a common problem causing inhibition of anaerobic digestion, and digesters treating highly concentrated wastes, such as food and municipal solid waste, and concentrated animal manure, are likely to suffer from partial or complete inhibition of methane-producing consortia, including methanogens. When grass clippings were added at the onset of anaerobic digestion of acetate containing a sodium concentration of 7.8 gNa(+)/L, a total methane production about 8L/L was obtained, whereas no methane was produced in the absence of grass leaves. In an attempt to narrow down which components of grass leaves caused decrease of sodium toxicity, different hypotheses were tested. Results revealed that betaine could be a significant compound in grass leaves causing reduction to sodium inhibition.
Publisher: IWA Publishing
Date: 10-1996
Abstract: The beneficial use of wastewater sludge is to some extent restricted by the presence of human pathogens. Following a risk assessment and monitoring programme it was found that the pathogen which posed the highest potential risk of infection in treated sludge was Giardia. Giardia cyst concentrations were found to be approximately 900/g wet weight of sludge following anaerobic digestion, although not all of the cysts may have been infective. In further studies three methods of wastewater sludge disposal or treatment were investigated. Anaerobically digested and mechanically dewatered sludge was stored for up to 60 weeks, incorporated into sandy soil and composted on a laboratory scale. Giardia cysts remained at levels which could be considered a public health concern after storage of sludge for over one year and after composting. However, cysts appeared to be destroyed within 12 weeks following soil amendment. The implications of the presence of Giardia for sludge disposal are discussed.
Publisher: Elsevier BV
Date: 12-2017
DOI: 10.1016/J.BIORTECH.2017.08.095
Abstract: Bioelectrochemical system (BES) can act as an auxiliary technology for improving organic waste treatment and biogas production in anaerobic digestion (AD). For the first time this study directly compared the performance of a single- and a cation-exchange membrane-equipped two-chamber BES-AD systems at thermophilic conditions. The results indicated that an active glucose-fed thermophilic anaerobic sludge could readily (<3days) increase biogas production in both reactor configurations by inserting a carbon electrode poised at -0.8V (vs. Ag/AgCl). However, after a 3-week operation, the biogas production rates from the single- and two-chamber BES reactor decreased due to volatile fatty acids accumulation. Only the two-chamber configuration could enable methane enrichment (98% CH
Publisher: AIP
Date: 2007
DOI: 10.1063/1.2806092
Publisher: IWA Publishing
Date: 09-2001
Abstract: In the past sewage ponding in indigenous settlements was commonplace as a result of overcrowding combined with inappropriate septic tank and leach drain design, installation and operation. The response over the past 10 years has been to develop reticulated sewerage systems to lagoons when the funds become available. These are often successful in terms of operation, improved public health and low maintenance but are expensive and wasteful of limited water supplies. Evapotranspiration (ET) is an effective method for on-site domestic effluent disposal in areas of Western Australia with soils of low permeability. Evapotranspiration systems have been established in a number of communities both for research/demonstration and as specified by architects. The systems usually follow two septic tanks for the disposal of all domestic effluent. A case study will be presented for a remote indigenous community where the ET systems installed for greywater only have been monitored over the last two years since installation. The use of evapotranspiration has enabled reuse of effluent for successful ex les of revegetation and food production and points to the need for a holistic approach to design and service delivery in these communities that includes a total environmental management plan.
Publisher: IWA Publishing
Date: 03-1995
Abstract: The storage of wastewater sludge as a possible low-cost means of pathogen reduction prior to its beneficial reuse was examined. However, after a 12 month storage period levels of Salmonella, faecal coliforms and streptococci, and Giardia cysts were too high for simple storage to be considered an adequate treatment option.
Publisher: Elsevier BV
Date: 08-1996
Publisher: IWA Publishing
Date: 09-2001
Abstract: Domestic wastewater reuse is currently not permitted anywhere in Australia but is widely supported by the community, promoted by researchers, and improvised by up to 20% of householders. Its widespread implementation will make an enormous contribution to the sustainability of water resources. Integrated with other strategies in the outdoor living environment of settlements in arid lands, great benefit will be derived. This paper describes six options for wastewater reuse under research by the Remote Area Developments Group (RADG) at Murdoch University and case studies are given where productive use is being made for revegetation and food production strategies at household and community scales. Pollution control techniques, public health precautions and maintenance requirements are described. The special case of remote Aboriginal communities is explained where prototype systems have been installed by RADG to generate windbreaks and orchards. New Australian design standards and draft guidelines for domestic greywater reuse produced by the Western Australian State government agencies for mainstream communities are evaluated. It is recommended that dry composting toilets be coupled with domestic greywater reuse and the various types available in Australia are described. For situations where only the flushing toilet will suffice the unique “wet composting” system can be used and this also is described. A vision for household and community-scale on-site application is presented.
Publisher: University of Queensland Library
Date: 1970
DOI: 10.14264/B5CA734
Publisher: Elsevier BV
Date: 02-2019
Publisher: Elsevier BV
Date: 03-1992
Publisher: Informa UK Limited
Date: 2013
Publisher: IWA Publishing
Date: 1999
Publisher: Informa UK Limited
Date: 09-2009
Publisher: IWA Publishing
Date: 05-2005
Abstract: This paper describes the performance of reedbeds using plastic (PET) bottle segments as an alternative low-cost media for the treatment of domestic greywater in Monteverde, Costa Rica, Central America. Twelve reedbeds consisting of four sets of triplicates were monitored through wet and dry seasons in order to determine the effect of media type (PET versus crushed rock) and the effect of plants. In both seasons, performance of the planted reedbeds with PET media, for BOD and fecal coliform removal, was either comparable to, or better than, that of the crushed rock systems. The planted PET reedbeds achieved fecal coliform removal rates & .9% in all cases equating to reductions of between 3 and nearly 5 log, with an average BOD outflow of 12.9 mg/L over both seasons. The hydraulic loading rate varied between 1.33 and 2.67 cm/day and hydraulic retention times (HRT) ranged from 3.5 to 7.5 days. The six reedbeds planted with Coix lacryma-jobi proved to be significantly more effective in pathogen removal and BOD reduction than the unplanted reedbeds. The planted PET reedbeds also increased their biomass by twice that of the planted crushed rock reedbeds during the study period. The majority of this increase was shown to be due to root growth. This paper discusses the implications of the above results for developing countries and identifies potential areas for further research.
Publisher: IWA Publishing
Date: 12-2012
Abstract: Formative market research is the first step in developing evidence-based sanitation marketing programs. In Malawi, the design, implementation and evaluation of rural sanitation marketing programs has been limited. This study applied a mixed methodological approach to examine the dynamic interactions between the supply and demand of sanitation in three rural districts. The supply assessment identified an extremely limited range of latrine options. Sanitation suppliers reported very low household demand for their existing latrine options. An additional constraint reported by suppliers was householders' perception of a hardware subsidy for latrine construction. The demand assessment found a key constraint of constructing an unlined pit latrine was their short time-in-use (11–13 months). Householders expressed despondency at having to consistently rebuild collapsed, unlined pit latrines. For brick-lined latrines, a key barrier was affordability combined with an over-estimation of construction costs. Key motivations to construct brick-lined latrines included product attributes and social drivers. Wide variations in access to income and use of micro-finance organizations were recorded within and across the study sites. Formative market research is an iterative process from which new lines of investigation arise. This study provides information that will provide a foundation for the ongoing research, design, implementation and monitoring of rural sanitation marketing programs in Malawi.
Publisher: Elsevier BV
Date: 04-2000
Publisher: IWA Publishing
Date: 1997
Publisher: Elsevier BV
Date: 2020
Publisher: Elsevier BV
Date: 05-1996
Publisher: Elsevier BV
Date: 1985
Publisher: Elsevier BV
Date: 08-1968
Publisher: Springer Science and Business Media LLC
Date: 19-06-2017
DOI: 10.1038/S41522-017-0021-6
Abstract: Microbiomes of full-scale seawater reverse osmosis membranes are complex and subject to variation within and between membrane units. The pre-existing bacterial communities of unused membranes before operation have been largely ignored in biofouling studies. This study is novel as unused membranes were used as a critical benchmark for comparison. Fouled seawater reverse osmosis membrane biofilm communities from an array of autopsied membrane s les, following a 7-year operational life-span in a full-scale desalination plant in Western Australia, were characterised by 16S rRNA gene metabarcoding using the bacterial primers 515F and 806R. Communities were then compared based on fouling severity and s ling location. Microbiomes of proteobacterial predominance were detected on control unused membranes. However, fouled membrane communities differed significantly from those on unused membranes, reflecting that operational conditions select specific bacteria on the membrane surface. On fouled membranes, Proteobacteria were also predominant but families differed from those on unused membranes, followed by Bacteriodetes and Firmicutes . Betaproteobacteria correlated with stable, mature and thick biofilms such as those in severely fouled membranes or s les from the feed end of the membrane unit, while Alpha and Gammaproteobacteria were predominantly found in biofilms on fouled but visually clean, and moderately fouled s les or those from reject ends of membrane units. Gammaproteobacteria predominated the thin, compact biofilms at the mid-feed end of membrane units. The study also supported the importance of Caulobacterales and glycosphingolipid-producing bacteria, namely Sphingomonadales, Rhizobiales and Sphingobacteriia , in primary attachment and biofilm recalcitrance. Nitrate-and-nitrite-reducing bacteria such as Rhizobiales , Burkholderiales and some Pseudomonadales were also prevalent across all fouled membranes and appeared to be critical for ecological balance and biofilm maturation.
Publisher: Elsevier BV
Date: 08-2022
Publisher: Wiley
Date: 05-1995
Publisher: Elsevier BV
Date: 02-2006
Publisher: Springer Science and Business Media LLC
Date: 09-1989
DOI: 10.1007/BF00468992
Publisher: IWA Publishing
Date: 1996
Publisher: Elsevier BV
Date: 06-1994
Publisher: IWA Publishing
Date: 1998
Publisher: IWA Publishing
Date: 07-1998
Abstract: The addition of clay in the form of bauxite refining residue (red mud) prior to composting has been suggested as a way to control heavy metal mobility in compost. Leachability and plant availability of metals in a mixture of grass clippings and sawdust spiked with metal solution was markedly reduced during the composting process. The fate of metals in municipal solid waste compost applied to land was examined by using a sequential step extraction to investigate metal speciation (into exchangeable and bound to carbonate forms, to Mn & Fe oxides, to organic matter and in residue phase) in red mud amended compost. The effects of red mud and the composting process on metal speciation in the compost for Cd, Cr, Cu, Ni, Pb and Zn were investigated, and a comparison of some effects with biosolids compost was made. Addition of red mud reduced the metal mobility and the potential hazard of releasing metals from compost through promoted precipitation, adsorption and complexation of free metal cations to red mud. Red mud however, was not able to desorb metals bound to organic matter. Since most of the metals in the municipal solid waste were not usually bound to organic matter, the addition of red mud prior to composting fixed the free metal ions before they bound to this fraction. Results for Cr speciation are reported in this paper.
Publisher: Springer Science and Business Media LLC
Date: 09-02-2022
Publisher: Elsevier BV
Date: 12-2020
Publisher: American Chemical Society (ACS)
Date: 05-2008
DOI: 10.1021/ES8003969
Abstract: In analogy to the well established dependency of microbial reactions on the redox potential of the terminal electron acceptor, the dependency of the microbial activity in a highly active microbial fuel cell on the potential of the electron-accepting electrode (anode) in a microbial fuel cell (MFC) is investigated. An acetate-fed, pH-controlled MFC was operated for over 200 days to establish a highly active MFC anodic biofilm using ferricyanide as the catholyte and granular graphite as electrode material. From the Coulombic efficiency of 83% of the MFC the microbial activity could be recorded by online monitoring of the current. Our results suggest that (1) in analogy to the Michaelis-Menten kinetics a half-saturation anodic potential (here termed k(AP) value) could be established at which the microbial metabolic rate reached half its maximum rate. This k(AP) value was about -455 mV (vs Ag/AgCl) for our acetate-driven MFC and independent of the oxidation capacity of the cathodic half-cell (2) a critical AP (here termed AP(crit)) of about -420 mV (vs Ag/AgCl) was established that characterizes the bacterial saturation by the electron-accepting system. This critical potential appeared to characterize the maximum power output of the MFC. This information would be useful for modeling and optimization of microbial fuel cells and the relative comparison of different microbial consortia at the anode.
Publisher: IWA Publishing
Date: 08-2011
DOI: 10.2166/WST.2011.565
Abstract: Nitrogen removal performance and the ammonia-oxidising bacterial (AOB) community were assessed in the batch loaded 1.3 ha saturated surface vertical flow wetland at CSBP Ltd, a fertiliser and chemical manufacturer located in Kwinana, Western Australia. From September 2008 to October 2009 water quality was monitored and sediment s les collected for bacterial analyses. During the period of study the wetland received an average inflow of 1,109 m3/day with NH3-N = 40 mg/L and NO3-N = 23 mg/L. Effluent NH3-N and NO3-N were on average 31 and 25 mg/L, respectively. The overall NH3-N removal rate for the period was 1.2 g/m2/day indicating the nitrifying capacity of the wetland. The structure of the AOB community was analysed using group specific primers for the ammonia monooxygenase gene (amoA) by terminal restriction fragment length polymorphism and by clone libraries to identify key members. The majority of sequences obtained were most similar to Nitrosomonas sp. while Nitrosospira sp. was less frequent. Another two vertical flow wetlands, 0.8 ha each, were commissioned at CSBP in July 2009, since then the wetland in this study has received nitrified effluent from these two new cells.
Publisher: IWA Publishing
Date: 06-2013
DOI: 10.2166/WST.2013.208
Abstract: Anaerobic digestion of waste activated sludge (WAS) is relatively poor due to hydrolysis limitations. Acid and alkaline pretreatments are effective in enhancing hydrolysis leading to higher methane yields. However, chemical costs often prohibit full-scale application. In this study, 12 V two-chamber electrolysis using an anion exchange membrane alters sludge pH without chemical dosing. pH dropped from 6.9 to 2.5 in the anode chamber and increased to 10.1 in the cathode chamber within 15 h. The volatile suspended solids solubilisation of WAS was 31.1% in the anode chamber and 34.0% in the cathode chamber. As a result, dissolved chemical oxygen demand increased from 164 to 1,787 mg/L and 1,256 mg/L in the anode and cathode chambers, respectively. Remixing of sludge from the two chambers brought the pH back to 6.5, hence no chemical neutralisation was required prior to anaerobic digestion. Methane yield during anaerobic digestion at 20 d retention time was 31% higher than that of untreated sludge. An energy balance assessment indicated that the non-optimised process could approximately recover the energy (electricity) expended in the electrolysis process. With suitable optimisation of treatment time and voltages, significant energy savings would be expected in addition to the benefit of decreased sludge volume.
Publisher: Elsevier BV
Date: 12-2012
DOI: 10.1016/J.BIORTECH.2011.12.011
Abstract: A membraneless bioelectrochemical system - rotatable bio-electrochemical contactor (RBEC) consists of an array of rotatable electrode disks was developed to convert the chemical energy from wastewater organics (acetate) directly into electricity. Each rotatable electrode disk had an upper-air exposing and a lower-water submerging halves. Intermittent rotation (180°) enabled each halve to alternately serve as anode and cathode. Removal of chemical oxygen demand (COD) was increased by 15% (from 0.79 to 0.91 kg COD m(-3) d(-1)) by allowing electron flow from the lower to the upper disk halves. Coupling with a potentiostat could alleviate cathodic limitation and increased COD removal to 1.32 kg COD m(-3) day(-1) (HRT 5h). About 40% of the COD removed was via current, indicating that the biofilm could use the lower half disk as electron acceptor. The RBEC removed COD more energy-efficiently than conventional activated sludge processes as active aeration is not required (0.47 vs. 0.7-2.0 kW h kg COD(-1)).
Publisher: Elsevier BV
Date: 07-2009
DOI: 10.1016/J.WATRES.2009.04.031
Abstract: Safe reuse of animal wastes to capture energy and nutrients, through anaerobic digestion processes, is becoming an increasingly desirable solution to environmental pollution. Pathogen decay is the most important safety consideration and is in general, improved at elevated temperatures and longer hydraulic residence times. During routine s ling to assess pathogen decay in thermophilic digestion, an inversely proportional relationship between levels of Clostridium perfringens and gas production was observed. Further s les were collected from pilot-scale, bench-scale thermophilic reactors and batch scale vials to assess whether gas production (predominantly methane) could be a useful indicator of decay of the thermotolerant pathogens C. perfringens and C ylobacter jejuni. Pathogen levels did appear to be lower where gas production and levels of methanogens were higher. This was evident at each operating temperature (50, 57, 65 degrees C) in the pilot-scale thermophilic digesters, although higher temperatures also reduced the numbers of pathogens detected. When methane production was higher, either when feed rate was increased, or pH was lowered from 8.2 (piggery wastewater) to 6.5, lower numbers of pathogens were detected. Although a number of related factors are known to influence the amount and rate of methane production, it may be a useful indicator of the removal of the pathogens C. perfringens and C. jejuni.
Publisher: Elsevier BV
Date: 05-1997
Publisher: Elsevier BV
Date: 08-1970
Publisher: Elsevier BV
Date: 09-2006
DOI: 10.1016/J.BIORTECH.2010.04.012
Abstract: It was desired to study a simplified method of cellulase production using solid-state fermentation for its potential to be used on-site as part of a cellulose to ethanol conversion process, in lieu of expensive and energy intensive commercial enzyme preparations. Crude unprocessed cellulase extracts were produced by solid-state fermentation of Trichoderma reesei on ground wheat straw. While cellulase yields were not high they were sufficient to produce ethanol from wheat straw in simultaneous saccharification and fermentation with Saccharomyces cerevisiae. As little as an additional 5% of the material converted to ethanol may be employed for cellulase production suggesting an inordinate quantity of additional substrate would not be required. These findings suggest a simplified crude cellulase process at the site of ethanol production using a common lignocellulosic substrate may be employed in lieu of commercial enzyme preparations.
Publisher: Elsevier BV
Date: 02-2015
Publisher: Elsevier BV
Date: 06-2015
Publisher: Elsevier
Date: 1998
Publisher: Springer Science and Business Media LLC
Date: 07-2025
DOI: 10.1007/S11356-016-6858-Z
Abstract: Biofilters are used for the conversion of odorous hydrogen sulphide to odourless sulphate in wastewater treatment plants under the right conditions of moisture and pH. One of the consequences of maintaining the suitable pH and moisture content is the production of large volumes of weakly acidic leachate. This paper presents a biofilter with a maximum H2S elimination capacity of 16.3 g m(-3) h(-1) and removal efficiency greater than 95 % which produces small volumes (1 mL of solution L(-1) of reactor day(-1)) of sulphuric acid with a concentration greater than 5.5 M after 150 days of continuous operation. The concentrated sulphuric acid was produced by intermittently trickling a minimum amount of nutrient solution down the upflow biofilter which created a moisture and pH gradient within the biofilter resulting in an environment at the top for the bacterial conversion of H2S, while sulphuric acid was accumulated at the base. Genetic ersity profiling of s les taken from different sections of the biofilter confirms that the upper sections of the biofilter had the best environment for the bacteria to convert H2S to sulphate. The formation of concentrated sulphuric acid presents an opportunity for the recovery of sulphur from the waste stream as a usable product.
Publisher: Elsevier BV
Date: 02-2016
DOI: 10.1016/J.CHEMOSPHERE.2015.08.048
Abstract: A novel biofilter that removes ammonia from air streams and converts it to nitrogen gas has been developed and operated continuously for 300 days. The ammonia from the incoming up-flow air stream is first absorbed into water and the carrier material, zeolite. A continuous gravity reflux of condensed water from the exit of the biofilter provides moisture for nitrifying bacteria to develop and convert dissolved ammonia (ammonium) to nitrite/nitrate. The down-flow of the condensed water reflux washes down nitrite/nitrate preventing ammonium and nitrite/nitrate accumulation at the top region of the biofilter. The evaporation caused by the inflow air leads to the accumulation of nitrite to extremely high concentrations in the bottom of the biofilter. The high nitrite concentrations favour the spontaneous chemical oxidation of ammonium by nitrite to nitrogen (N2). Tests showed that this chemical reaction was catalysed by the zeolite filter medium and allowed it to take place at room temperature. This study shows that ammonia can be removed from air streams and converted to N2 in a fully aerated single step biofilter. The process also overcomes the problem of microorganism-inhibition and resulted in zero leachate production.
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.
Publisher: Elsevier BV
Date: 09-1996
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 08-2019
Publisher: Elsevier
Date: 2017
Publisher: Elsevier BV
Date: 2001
Publisher: Elsevier BV
Date: 05-2003
Publisher: Wiley
Date: 24-04-2006
DOI: 10.1002/JCTB.1530
Publisher: Elsevier BV
Date: 08-2009
DOI: 10.1016/J.BIORTECH.2009.01.017
Abstract: This study was undertaken to assess the toxicological risks from sodium accumulation in a vermifiltration wastewater treatment system to the key worm species, Eisenia fetida. The study found that sodium chloride (NaCl) is the more toxic of the common sodium salts found in wastewater to the worms. The research further found that the worms have an ability to detoxify NaCl although reproduction will be impaired if the worms are exposed to moderate concentrations of NaCl for a long period of time. The actual risk from NaCl toxicity in the vermifiltration process was low however. The low risk was due to the low solid-water partitioning constant of NaCl, which led to a very low predicted environmental concentration (PEC) for NaCl.
Publisher: Elsevier BV
Date: 07-2014
Publisher: Elsevier BV
Date: 02-2009
Publisher: American Chemical Society (ACS)
Date: 03-1992
DOI: 10.1021/IE00003A047
Publisher: World Scientific Pub Co Pte Lt
Date: 12-2015
DOI: 10.1142/S0219607715500068
Abstract: This paper provides an overview of food waste in the context of food security, resources management and environment health. It compares approaches taken by various governments, community groups, civil societies and private sector organisations to reduce food waste in the developed and developing countries. What constitutes ‘food waste’ is not as simple as it may appear due to erse food waste measurement protocols and different data documentation methods used worldwide. There is a need to improve food waste data collection methods and implementation of effective strategies, policies and actions to reduce food waste. Global initiatives are urgently needed to: enhance awareness of the value of food encourage countries to develop policies that motivate community and businesses to reduce food waste encourage and provide assistance to needy countries for improving markets, transport and storage infrastructure to minimise food waste across the value chain and, develop incentives that encourage businesses to donate food. In some countries, particularly in Europe, initiatives on food waste management have started to gain momentum. Food waste is a global problem and it needs urgent attention and integrated actions of stakeholders across the food value chain to develop global solutions for the present and future generations.
Publisher: Informa UK Limited
Date: 14-07-2016
DOI: 10.1080/09593330.2015.1063706
Abstract: This paper describes the development and experimental evaluation of a novel bubble column-based humidification-dehumidification system, for small-scale desalination of saline groundwater or seawater in remote regions. A bubble evaporator prototype was built and matched with a simple flat-plate type condenser for concept assessment. Consistent bubble evaporation rates of between 80 and 88 ml per hour were demonstrated. Particular focus was on the performance of the simple condenser prototype, manufactured from rectangular polyvinylchlorid plastic pipe and copper sheet, a material with a high thermal conductivity that quickly allows for conduction of the heat energy. Under laboratory conditions, a long narrow condenser model of 1500 mm length and 100 mm width achieved condensate recovery rates of around 73%, without the need for external cooling. The condenser prototype was assessed under a range of different physical conditions, that is, external water cooling, partial insulation and aspects of air circulation, via implementing an internal honeycomb screen structure. Estimated by extrapolation, an up-scaled bubble desalination system with a 1 m2 condenser may produce around 19 l of distilled water per day. Sodium chloride salt removal was found to be highly effective with condensate salt concentrations between 70 and 135 µS. Based on findings and with the intent to reduce material cost of the system, a shorter condenser length of 750 mm for the non-cooled (passive) condenser and of 500 mm for the water-cooled condenser was considered to be equally efficient as the experimentally evaluated prototype of 1500 mm length.
Publisher: Elsevier BV
Date: 07-2021
Publisher: American Society of Civil Engineers (ASCE)
Date: 08-1984
Publisher: IWA Publishing
Date: 12-2004
Abstract: The insertion of a single baffle into a laboratory septic tank to mix incoming feed with sludge has been shown to improve anaerobic degradation of the feed. This is particularly true of soluble organic matter such as glucose. Oil or cellulose fed separately does not undergo degradation. It is expected however that a balanced feed such as sewage will be better degraded.
Publisher: IWA Publishing
Date: 03-2006
DOI: 10.2166/WS.2006.041
Abstract: Integrated Urban Water Management (IUWM) in land developments is becoming increasingly necessary in order to more efficiently utilise and manage water resources. Techniques including the control of stormwater runoff, increasing infiltration and providing opportunities for retention, treatment and reuse of both stormwater and wastewater, are well suited to being designed into the development rather than considered post-construction or not at all. There can be extensive capital investment by developers to implement IUWM which is often not returned in the land sales. This produces a disincentive for the developer unless the contribution is recognised and rewarded either financially or with appropriate marketing advantage. A system to rate land developments based upon IUWM has been developed that would quantifiably assess how effectively water resources would be utilised in a proposed land development. This assessment would provide a point of comparison between developments allowing property purchasers, developers, utilities and legislators to quickly compare how well the development performs in terms of IUWM, providing a mechanism for financial reward or recognition. This paper discusses the development of a model to quantifiably assess land developments for water efficient use and introduces a rating system with which land developments can be compared in terms of IUWM.
Publisher: Elsevier BV
Date: 03-2016
Publisher: Elsevier BV
Date: 04-1992
Publisher: Elsevier BV
Date: 02-2009
DOI: 10.1016/J.BIOELECHEM.2008.10.002
Abstract: Electrochemically active bacteria in a microbial fuel cell (MFC) usually exist as a biofilm attached to an electrode surface. Conventional cyclic voltammetry using potentiostat is considered as a powerful and reliable method to study electrochemical behavior of MFC biofilm. In this paper, we introduce a new approach to evaluate redox behavior of an electro-active MFC biofilm without using a potentiostat. Analogous to a conventional cyclic voltammetry study, we controlled the biofilm-electrode potential by computer-feedback controlling the external resistance of an operating MFC. In this way, the MFC can still operate as a "fuel cell" without being "interrupted" by an external device (i.e. potentiostat) that normally does not belong to the system. Relationship between current and biofilm-electrode potential was obtained and showed agreement with a potentiostat-controlled method under similar experimental conditions. The method could be added to our technical repertoire for analysis of bacterial mediator involved in the exocellular electron transfer of a MFC-biofilm, and it could potentially serve as a practical process monitoring method for MFC operation. The application of computer-control components should be further explored to facilitate control, diagnosis as well as optimization of MFC processes.
Publisher: Elsevier BV
Date: 11-2015
Publisher: Elsevier BV
Date: 05-2019
Publisher: IWA Publishing
Date: 12-2004
Abstract: Globally we are faced with billions of people without access to safe water and adequate sanitation. These are generally located in developing communities. Even in developed communities the current large scale systems for supplying water, collecting wastewater and treating it are not environmentally sustainable, because it is difficult to close the cycle of water and nutrients. This paper discusses the advantages of small scale water and wastewater systems in overcoming the difficulties in providing water and wastewater systems in developing communities and in achieving sustainability in both developed and developing communities. Particular attention is given to technology and technology choice, even though technology alone does not provide the complete answer. Disadvantages of small scale systems and how they may be overcome are discussed.
Publisher: Springer Science and Business Media LLC
Date: 04-07-2015
Publisher: IWA Publishing
Date: 11-2002
Abstract: This paper deals with the characteristics and treatment options of septage. The objective of the paper is to evaluate the effects of co-treatment of 50 MLD of septage in a sewage treatment pond system. The treatment efficiency of the pond system for BOD5 and Fecal Coliform (FC) has been estimated using a first order kinetics model. The model has predicted that the treatment pond system has a maximum capacity of 8.5 MLD and will have a reserve of 28.3% of its total capacity even after the proposed addition of 50 MLD of septage. Separation of oil and grease from septage prior to discharge into the pond system is recommended.
Publisher: Elsevier BV
Date: 06-2014
Publisher: Informa UK Limited
Date: 11-2001
DOI: 10.1080/09593330.2001.9619170
Abstract: A number of waste solutions from processes operating in Western Australia (anaerobic digester supernatants, facultative lagoon treated piggery and abattoir waste effluents) were characterised chemically and by automated titration to determine acid-base characteristics. Titrations were over the pH range 2-12 or less. All waste solutions were excess molar ratios of NH3-N to PO4-P (5:1 up to 20:1). The amounts of acid or base reagent required for each waste solution type were in the sequence anaerobic digestor supernatant>>piggery effluent>abattoir effluent. The most efficient removal of N and P of the field s les considered is from piggery effluent. The results indicate conditions for optmising the removal of N and P by precipitation (predominantly struvite) as well as the way forward in determining the full scope of N and P waste streams for which recycling by precipitation (either magnesium or calcium based salts) may be feasible.
Publisher: IWA Publishing
Date: 09-2001
Abstract: Limited water resources exist in numerous remote indigenous settlements around Australia. Indigenous people in these communities are still living in rudimentary conditions while their urban counterparts have full amenities, large scale water supplies and behavioral practices which may not be appropriate for an arid continent but are supported by extensive infrastructure in higher rainfall coastal areas. As remote indigenous communities continue to develop, their water use will increase, and in some cases, costly solutions may have to be implemented to augment supplies. Water harvesting techniques have been applied in settlements on a small scale for domestic and municipal purposes, and in the large, broadacre farm setting for productive use of the water. The techniques discussed include swales, infiltration basins, infiltration trenches and “sand dam” basins. This paper reviews the applications of water harvesting relevant to small communities for land rehabilitation, landscaping and flood control. Landscaping is important in these communities as it provides shelter from the sun and wind, reduces soil erosion and hence reduced airborne dust, and in some cases provides food and nutrition. Case studies of water harvesting systems applied in the Pilbara Region, Western Australia for landscaping around single dwellings in Jigalong and Cheeditha, in a permaculture garden in Wittenoon and at a college and carpark in Karratha are described.
Publisher: Elsevier BV
Date: 02-2017
Publisher: IWA Publishing
Date: 19-12-2015
Abstract: This study examines diffusion theory as an explanatory framework for the adoption of an ecological toilet by ‘first-moving’ customers in an urban setting in Malawi. The study was conducted during the early stages of a social marketing programme. A pragmatic paradigm was applied to address three research questions using mixed methods. The qualitative investigation formed the primary component of the study and interviewed 14 customers who were selected to receive micro-finance loans to purchase the ecological toilet. These 14 customers were labelled ‘first movers’. The study identified that ‘first movers’ only partially displayed characteristics of ‘innovators’ and the product met three of five characteristics associated with successful rates of diffusion. Improving the trialability and simplicity of the product, through field-testing, human-centred or participatory design approaches could improve the likelihood of the product attaining the characteristics that support successful diffusion. Organisations that apply social marketing approaches to improve urban sanitation coverage may improve their efficacy, equity and cost-effectiveness by utilising diffusion theory as the theoretical framework to design, implement and evaluate their programmes.
Publisher: Elsevier BV
Date: 1999
Publisher: Elsevier BV
Date: 2017
DOI: 10.1016/J.SCITOTENV.2016.09.136
Abstract: A quantitative framework for sustainable desalination planning in metropolitan areas, which integrates the tools of mixed integer linear programming and life cycle assessment, is presented. The life cycle optimisation framework allows for optimal desalination planning by considering choices over intake type, staging and location of the infrastructure under different land-use, environmental and economic policies. Optimality is defined by the decision maker's selected objective function, being either an environmental impact or a levelised cost indicator. The framework was tested for future desalination planning scenarios in the northern metropolitan area of Perth, Western Australia. Results indicate that multi-staged construction and decentralised planning solutions may produce lower life cycle environmental impacts (58%) and at a lower levelised cost (24%) than a centralised desalination solution currently being considered by Western Australian water planners. Sensitivity analysis results suggest that the better environmental and economic performance of decentralised planning over centralised planning is highly sensitive to the proportion of land that can be made available for the siting of decentralised plants near the demand zone. Insight into land use policies is a critical factor to the initiation and success of decentralised solution in developed metropolitan areas.
Publisher: IWA Publishing
Date: 10-2008
DOI: 10.2166/WST.2008.478
Abstract: This study was undertaken to assess the toxicity of ammonia/ammonium to key species within the vermifiltration process. The key species, the earthworm Eisenia fetida, was subjected to a series of tests in solid phase mesocosms and full-scale units. The solid phase tests showed a relatively low toxicity to ammonium with ammonium chloride having an LC50 for ammonium of 1.49 g/kg. Ammonium sulfate did not show an effect on mortality at 2 g/kg ammonium. The full-scale units showed that ammonia hydroxide can change the pH and concentration of ammonia in wastewater and while it caused some mortality to the worms its overall affect on system functioning was minimal with no significant difference in terms of worm survival found between treatments. The affect on nitrifying bacteria was also minimal with no linear trend shown with ammonia concentration.
Publisher: Elsevier BV
Date: 08-2013
Publisher: Informa UK Limited
Date: 06-10-2016
Publisher: IWA Publishing
Date: 12-2004
Abstract: Organic waste management is a growing issue due to the unsustainable practices of its disposal. Sewage treatment plants are designed to treat wastewater to produce a safe effluent. However, one of the by-products, the sewage sludge which is disposed off in landfill or used as fertilizer in agricultural operation is high in pathogens. Sustainability can be achieved by Vermicomposting of organic matter which involves accelerated cycling of nutrients though a closed cycle whereby waste products are put to productive end use. Vermicomposting and vermifiltration are natural waste management processes relying on the use of worms to convert organic wastes to stable soil enriching compounds. Domestic wastewater management can be accommodated through these processes in a sustainable manner. A considerable reduction in pathogens has been noticed in the end product to a level that it can be safely applied to land. This paper provides an overview of the system characteristics of management systems utilising vermiculture, to manage wastewater. The process can be used in a small scale for household waste treatment to rural or urban waste management.
Publisher: IWA Publishing
Date: 12-1994
Abstract: Biological destabilisation of the wool grease/water emulsion in wool scouring effluent using anaerobic bacterial activity (biological flocculation) was investigated. The aim of biological flocculation is to remove the bulk of wool grease which is the major source of COD, therefore serving as a pretreatment step, prior to classical biological processes either aerobic or anaerobic. In a semi-continuous system, a two-stage anaerobic bioflocculation process was employed to treat a high grease (& 15 g l−1) wool scouring effluent (WSE). After 110 days of operation, the process showed removal of 70 to 90% grease at a combined hydraulic residence time (HRT) of 4 to 10 days. With low grease (& 10 g l−1) WSE grease removal was lower. At an HRT of 3 days a single stage bioflocculation process removed 40% grease. The supernatant from the process was easily treated by activated sludge process reducing grease concentration from about 1.5 g l−1 to less than 0.1 g l−1 in the final effluent (HRT 3 days). Methane production of the process was negligible. Most of the grease was removed by flocculation as a result of anaerobic bacterial activity. The mechanisms of the process were investigated by a series of batch experiments and found to be (1) appropriate gentle mixing between WSE and anaerobic sludge results in the absorption of wool grease from the liquid to the sludge phase, (2) further destablisation of the wool grease emulsion is obtained when the mixed liquor is left undisturbed. The latter was due to bacterial activity and growth on organics contained in WSE.
Publisher: Springer Science and Business Media LLC
Date: 27-07-2021
Publisher: IWA Publishing
Date: 05-2011
DOI: 10.2166/WST.2011.399
Abstract: Alternate water sources are being implemented in urban areas to augment scheme water supplied by a water utility to homes. These sources include residential wells, rainwater tanks and greywater systems. Greater water efficiency can be achieved when these systems are designed to match a water source to a given demand based on both water quantity and quality parameters. In this way the use of an alternate water source can be maximised and the use of the high quality scheme water minimised. This paper examines the use of multiple alternate water sources sequentially to supply the same demand point potentially optimising the use of all available water sources. It also allows correct sizing of such water systems and their components to reduce scheme water demand. A decision support tool based on water balance modelling was developed that considers such water options at the household scale. Application of this tool to eight scenarios for both large and small house lots shows that using alternate water sources in idually can result in significant scheme water savings. However by integrating these sources additional scheme water saving can be made.
Publisher: American Chemical Society (ACS)
Date: 02-12-2010
DOI: 10.1021/ES9023833
Abstract: Poor cathodic oxygen reduction and the detrimental buildup of a pH gradient between anode and cathode are the major hurdles in the development of sustainable microbial fuel cells (MFCs). This article describes and tests a concept that can help overcoming both of these limitations, by inverting the polarity of the MFC repeatedly, allowing anodic and cathodic reactions to occur alternately in the same half-cell and hence neutralizing its respective pH effects. For simplicity, we studied polarity inversion exclusively in one half-cell, maintaining its potential at -300 mV (vs Ag/AgCl) by a potentiostat. An alternating supply of acetate and dissolved oxygen to the biofilm resulted in the tested half-cell repeatedly changing from an anode to a cathode and vice versa. This repeated inversion of current direction avoided the detrimental drifting of the electrolyte pH. Control runs without current inversion ceased to produce current, as a result of anode acidification. The presence of the anodophilic biofilm survived the intermittent oxygen exposure and could measurably facilitate the cathodic reaction by reducing the apparent oxygen overpotential. It enabled cathodic oxygen reduction at about -150 mV (vs Ag/AgCl) compared to -300 mV (vs Ag/AgCl) for the same electrode material (granular graphite) without biofilm. Provided that a suitable cathodic potential was chosen, the presence of "anodophilic bacteria" at the cathode could enable a 5-fold increase in power output. Overall, the ability of an electrochemically active biofilm to catalyze both substrate oxidation and cathodic oxygen reduction in a single bioelectrochemical system has been documented. This property could be useful to alleviate both the cathodic oxygen reduction and the detrimental drifting of electrolyte pH in an MFC system. Further research is warranted to explore the application of such bidirectional microbial catalytic properties for sustainable MFC processes.
Publisher: Elsevier
Date: 2018
Publisher: Elsevier BV
Date: 08-2004
Publisher: IWA Publishing
Date: 16-04-2019
DOI: 10.2166/WPT.2019.028
Abstract: Householders in cities face water-related issues due to the increasing cost and restrictions in water use, especially during drought. They respond in many different ways, ranging from installing water efficient appliances, adopting water-saving behavior and implementing greywater reuse, to being water self reliant (off-mains supply). The latter approach should consider using only rainwater falling on the property boundaries, and if self-supply is from groundwater it should be derived from rainwater falling on the property. Therefore, sustainability depends on the annual rainfall, size of property and availability of storage for water to be used during periods without rainfall. In principle any house can be retrofitted to rely solely on rainwater, because technologies exist to treat subsequent wastewater to any quality desired for reuse. However, the energy requirement and investment needed may negate overall sustainability. Very few studies have assessed water use in households to determine whether relying solely on rainwater is practical or sustainable in the long-term. Three case studies in Perth, Western Australia are reported here, where water auditing has been used for sustainability assessment.
Publisher: Elsevier BV
Date: 09-2006
DOI: 10.1016/J.BIORTECH.2005.06.012
Abstract: The effect of heavy metals Cu and Zn on dehydrogenase and protease activity of the substrate during vermicomposting was investigated. Three dosages of Cu and Zn were tested in mesocosm experiments to investigate their bioaccumulation and impact on the reproduction of Eisenia fetida. Cu accumulated within the worm tissues in dosage concentrations up to a maximum level of 213 mg Cu kg(-1). The number of juveniles decreased from the lowest to highest dosages of Cu and Zn after 10 weeks of the experiment. Dehydrogenase showed a strong negative correlation (P < 0.01) with increased dosage of Cu, while protease remained unaffected. An overall reduction on dehydrogenase activity with increasing dosages of Cu and Zn indicated that these metals would impact detrimentally on the soil microbiology and consequently the stabilisation of the dosed media.
Publisher: IWA Publishing
Date: 04-2007
DOI: 10.2166/WST.2007.147
Abstract: The development of innovative decentralised wastewater treatment systems is pertinent to environmental sustainability. However for their appropriate use they require significant research and design to ensure they can be relied upon in the future and in most cases they have received less attention and research than large-scale sewage systems. This study assessed the likelihood of biological inhibition and disruption from pH to key species for vermifiltration. The test firstly assessed the buffer capacity of a vermicompost+manure media finding it had a relatively high buffering capacity for pH. The toxicity after the buffer capacity experiment showed that the species would survive between pH levels of 6.2 and 9.7. At the higher and lower pH levels however the survival of juveniles was impaired, probably due to their ability to uptake greater amounts of soluble salts and inability to regulate them. Overall the study showed that the tolerance of the key vermifiltration species to pH was far less than their survival as previously proposed and further research assessing their long-term population dynamics in a vermifiltration system with pH is warranted.
Publisher: Elsevier BV
Date: 2017
Publisher: Elsevier BV
Date: 12-2012
Publisher: IWA Publishing
Date: 03-2006
DOI: 10.2166/WST.2006.198
Abstract: The Woodman Point Wastewater Treatment Plant (WWTP) in Western Australia has experienced two separate problems causing avoidable maintenance costs: the build-up of massive struvite (MgNH4PO4· 6H2O) scaling downstream of the anaerobic digester and the formation of hydrogen sulfide (H2S) levels in the digester gas to levels that compromised gas engine operation and caused high operating costs on the gas scrubber. As both problems hang together with a chemical imbalance in the anaerobic digester, we decided to investigate whether both problems could be (feasibly and economically) addressed by a common solution (such as dosing of iron solutions to precipitate both sulfide and phosphate), or by using separate approaches. Laboratory results showed that, the hydrogen sulfide emission in digesters could be effectively and economically controlled by the addition of iron dosing. Slightly higher than the theoretical value of 1.5 mol of FeCl3 was required to precipitate 1 mol of dissolved sulfide inside the digester. Due to the high concentration of PO43− in the digested sludge liquor, significantly higher iron is required for struvite precipitation. Iron dosing did not appear an economic solution for struvite control via iron phosphate formation. By taking advantage of the natural tendency of struvite formation in the digester liquid, it is possible to reduce the risk of struvite precipitation in and around the sludge-dewatering centrifuge by increasing the pH to precipitate struvite out before passing through the centrifuge. However, as the Mg2+ /PO43− molar ratio in digested sludge was low, by increasing the pH alone (using NaOH) the precipitation of PO43− was limited by the amount of cations (Ca2+ and Mg2+ ) available in the sludge. Although this would reduce struvite precipitation in the centrifuge, it could not significantly reduce PO43− recycling back to the plant. For long-term operation, maximum PO43− reduction should be the ultimate aim to minimise PO43− accumulation in the plant. Magnesium hydroxide liquid (MHL) was found to be the most cost-effective chemical to achieve this goal. It enhanced struvite precipitation from both, digested sludge and centrate to the point where more than 95% PO43− reduction in the digested sludge was achieved.
Publisher: IWA Publishing
Date: 09-2010
DOI: 10.2166/WPT.2010.047
Abstract: Decentralised wastewater recycling and irrigation systems have been established with industry partners in Perth urban villages. The project is now monitoring and evaluating these systems for performance and reliability to meet regulatory standards, effects on soil and vegetation, pathogen disinfection, nutrients prevented from infiltration to groundwater or infiltrated and recycled, maintenance issues of the systems and the effective amount of scheme and bore water saved in the long term. Three trial sites were established for the Premier's Water Foundation (PWF) (Bridgewater Lifestyle Village 389 household greywater recycling Timbers Edge Resort Village 260 houses to common greywater recycling Banksia Tourist Village 162 park homes to common wastewater treatment) The research team continues to conduct research on other promising sites (Somerville Ecovillage with 104 houses on dry composting toilets and greywater recycling and Tuart Lakes Lifestyle Village with 415 park homes to common wastewater treatment). This paper provides an overview of the results to date from five research topics: completed are a new regulatory framework, a technical elements model, and a new water balance and efficiency rating tool. For the fourth topic, trials found that mosquito control measures are effective. Fifthly, early monitoring results for a “zero emissions nutrients” (ZEN) model for urban land developments are promising with nutrient leaching within prescribed limits.
Publisher: Elsevier BV
Date: 09-2017
Publisher: IWA Publishing
Date: 09-2001
Abstract: Rainwater, borewater and catchment water are used for domestic water supply purposes with or without treatment in remote areas around the world. These places seldom have any facilities for routine testing of their drinking water. A simple on-site testing method is highly required in such areas. The H2S method has been tested for treated drinking water and was found to have a good correlation with the standard methods. The present study was aimed at assessing the suitability of the H2S method for testing different sources of drinking water. Since these types of water may contain H2S producing bacteria not of faecal origin the occurrence of false results in this method cannot be overruled. Therefore it was worthwhile to study whether the positive results are true positive results and what percentage of false positive and false negative results could be expected while using this test for routine analysis of water s les. Results were compared with the results using standard procedures for testing total coliforms, Escherichia coli and Salmonella spp. The present experiment analysed 121 rainwater s les, 17 borewater s les, 41 catchment water s les and 74 remote Aboriginal community water s les. Rainwater, borewater and catchment water s les gave true results of 78.5%, 82.3% and 80.5% respectively while the treated and untreated community s les gave true results of 93.7 and 84.6% respectively. It was concluded that in the developing countries where the acceptable level of total coliform is & MPN, the H2S method would be a good test to identify microbial contamination. In other regions, the H2S method could be used as a screening test for drinking water supplies.
Publisher: Inderscience Publishers
Date: 2013
Publisher: IWA Publishing
Date: 05-2005
Abstract: An overview of available onsite, small and community scale wastewater treatment technology shows that it is erse compared to current technology for centralised collection and treatment of wastewater. An analysis of the onsite, small and community scale technology for achieving sustainability shows that it more conducive to achieving sustainability than the centralised technology. It is likely, however, that its application is in remote and rural areas, where the technology should be improved and integrated with other technology sectors (energy, food production) for improved sustainability. Opportunities exist in new urban developments to achieve similar outcomes, but concerted efforts are required to demonstrate or showcase sustainability benefits in real situations. A huge potential also exists for the use of onsite, small and community scale technology in developing countries for achieving the same sustainability outcomes. It is likely to succeed if the technology is modified to be of lower cost but based on the same science, and that research, development and demonstrations in developed countries are shown to be successful.
Publisher: Elsevier BV
Date: 1985
Publisher: IWA Publishing
Date: 05-2005
Abstract: Small scale systems can improve the sustainability of sanitation systems as they more easily close the water and nutrient loops. They also provide alternate solutions to centrally managed large scale infrastructures. Appropriate sanitation provision can improve the lives of people with inadequate sanitation through health benefits, reuse products as well as reduce ecological impacts. In the literature there seems to be no compilation of a wide range of available onsite sanitation systems around the world that encompasses black and greywater treatment plus stand-alone dry and urine separation toilet systems. Seventy technologies have been identified and classified according to the different waste source streams. Sub-classification based on major treatment methods included aerobic digestion, composting and vermicomposting, anaerobic digestion, sand/soil eat filtration and constructed wetlands. Potential users or suppliers of sanitation systems can choose from wide range of technologies available and examine the different treatment principles used in the technologies. Sanitation systems need to be selected according to the local social, economic and environmental conditions and should aim to be sustainable.
Publisher: IWA Publishing
Date: 12-2008
DOI: 10.2166/WS.2008.112
Abstract: Drought across swathes of Australia, highlights our need for water conservation in addition to seeking new sources of water (demand and supply-side resource options). Water conservation or efficiency improvement is currently a non-systematic process along the lines of ‘if we do such and such then we will save so much water’. Such an approach is ad-hoc and only has the appearance of being ‘quantitative’. We would class it as qualitative, or maybe advanced qualitative water conservation. True quantitative or structured water auditing of non-domestic water consumption is an iterative, systematic and documented process of obtaining reliable use data, validated by a closure approach. Opportunities are identified for water use reduction, water reuse, recycling and for water resource substitution. Financial assessment of savings in cost against cost of measures will provide a payback period. A water management strategy or Water Management Plan (WMP) as it is known in Victoria, Australia, is devised which is consistent with legal requirements, the enterprise's environmental policy and its movement towards sustainable development. Regulators have legislated for mandatory WMPs and audits in Victoria, but this is the only state so far to do this. Mandatory water auditing should be an uncontested choice as it can only provide a win:win situation regulation to the private sector. We argue that only the systematic process provided by structural water auditing constitutes quantitative water conservation. Further, statutory obligation for water users to engage in the water auditing process will give the broad, systematic quantitative information, and based upon which optimal water management strategies or WMPs can be devised. This will ensure a rational approach to our future water needs and the needs of our environment. It is anticipated that voluntary auditing in the arenas not mandated will increase in the long term if this is done.
Publisher: SAGE Publications
Date: 04-02-2013
Abstract: Published national and state reports have revealed that Australia deposits an average of 16 million Mg of solid waste into landfills yearly, of which approximately 12.6% is comprised of food. Being highly biodegradable and possessing high energy content, anaerobic digestion offers an attractive treatment option alternative to landfilling. The present study attempted to identify the theoretical maximum benefit of food waste digestion in Australia with regard to energy recovery and waste ersion from landfills. The study also assessed the scope for anaerobic process to utilize waste for energy projects through various case study scenarios. Results indicated anaerobic digestion of total food waste generated across multiple sites in Australia could generate 558 453 dam 3 of methane which translated to 20.3 PJ of heating potential or 1915 GW e in electricity generation annually. This would contribute to 3.5% of total current energy supply from renewable sources. Energy contribution from anaerobic digestion of food waste to the total energy requirement in Australia remains low, partially due to the high energy consumption of the country. However its appropriateness in low density regions, which are prevalent in Australia, may allow digesters to have a niche application in the country.
Publisher: IWA Publishing
Date: 05-2005
Abstract: Integrated Urban Water Management (IUWM) seeks to extend Water Sensitive Urban Design to a total water cycle approach that includes reuse of wastewaters. This paper investigates the appropriateness of environmental technologies for application at a cluster scale in IUWM. Many environmental technologies are economically or physically unsuited to use on a municipal or unit scale. Cluster scale is a middle ground that will allow such environmental technologies to achieve full potential. The concept of cluster scale and the application of environmental technologies at this scale are discussed along with some ex les of suitable technologies.
Publisher: Oxford University Press (OUP)
Date: 09-2002
DOI: 10.1046/J.1472-765X.2002.01163.X
Abstract: The purpose of this study was to investigate the influence of co-substrates, such as glucose and cysteine, on the structure of microbial aggregates in anaerobic digesters treating oleate, a long-chain fatty acid (LCFA). Transmission electron microscopy (TEM) and confocal laser scanning microscopy (CLSM) were used to examine the structure of microbial aggregates. Fluorescence in situ hybridization (FISH) techniques were also used to characterize and localize the different trophic groups present in the aggregates. Oleate was found to inhibit the methanogenic activity and formation of granular biomass in digesters. The addition of co-substrates, such as glucose and cysteine either singly or in combination, increased the methanogenic activity and formation of granular biomass. Glucose was more effective than cysteine in reducing the inhibition by oleate on the methanogenic bacteria and in enhancing the formation of granules. The addition of nutrient substrate, such as glucose and cysteine could decrease the toxicity of LCFA on anaerobic granulation. The results suggest that the addition of other substrates might decrease the toxicity of LCFA on the granulation of biomass in anaerobic digesters and enhance methanogenic activity. A combination of TEM, CLSM and FISH techniques provides a better tool for visualizing microbial aggregates and for differentiating and localizing different microbial groups within these aggregates.
Publisher: Elsevier BV
Date: 05-1997
Publisher: EDP Sciences
Date: 2017
DOI: 10.1051/REES/2017027
Publisher: Elsevier BV
Date: 12-2021
Publisher: IWA Publishing
Date: 09-2009
DOI: 10.2166/WST.2009.472
Abstract: This study assessed copper and zinc distribution in the surface layer of sediment and rhizome tissue within the saturated surface vertical flow constructed wetland of CSBP Ltd, a fertiliser and chemical manufacturer located in Western Australia. Sediment and Schoenoplectus validus rhizome s les were collected at various distances from the inlet pipe while water s les are routinely collected. Water s les were analysed for nutrients and metals, sediments were analysed for total and bioavailable metals and rhizomes were analysed for total metals only. Mean influent copper and zinc concentrations were 0.19 mg/L and 0.24 mg/L respectively. The distribution of bioavailable Cu and Zn in the top sediment layer follows a horizontal profile. Analysis of variance (ANOVA) showed that the bioavailable fraction of these metals in sediments near the inlet pipe (30.2 mg/kg Cu and 60.4 mg/kg Zn) is significantly higher than in sediments at the farthest location (10.3 mg/kg Cu and 26.1 mg/kg Zn). The average total Cu concentration in the sediment at the 2 m location has reached the 65 mg/kg trigger value suggested by the Interim Sediment Quality Guidelines (ANZEEC 2000). Cu and Zn concentrations in the rhizome of S. validus do not vary significantly among different locations. Whether Cu and Zn concentrations at the CSBP wetland may reach toxic levels to plants and bacteria is still unknown and further research is required to address this issue. The surface component of the wetland favours sedimentation and binding of metals to the organic matter on the top of the sediment, furthermore, the sediment which tends to be anoxic with reducing conditions acts as a sink for metals.
Publisher: Elsevier BV
Date: 06-2018
Publisher: Elsevier BV
Date: 03-2001
DOI: 10.1016/S0043-1354(00)00352-3
Abstract: Composting is commonly used as an effective means of stabilizing wastewater biosolids and reducing pathogens to very low concentrations. However, it has been shown that under certain conditions Salmonella can regrow in previously composted biosolids. Growth of seeded Salmonella typhimurium in composted biosolids ranging from two weeks to two years maturity was monitored. Results from sterile and non-sterile composted biosolids were compared. Seeded S. typhimurium colonized rapidly in sterilized biosolids reaching a maximum population density of more than 10(8) g(-1). Growth of seeded S. typhimurium was suppressed in non-sterilized compost with a maximum population density of less than 10(3) g(-1). There was a significant decline in the growth rate of seeded Salmonella in sterilized compost when the compost was stored, suggesting that bio-available nutrients declined with storage. However, in non-sterilized compost this was not the case. This suggests that the indigenous microflora play a significant role in suppression of Salmonella regrowth in composted biosolids. There was a strong negative correlation (-0.85) between the Salmonella inactivation rate and the maturity of compost in non-sterilized compost. The Salmonella inactivation rate was seven times higher in biosolids composting for two weeks as compared to compost stored for two years. This suggests that the antagonistic effect of indigenous microorganisms towards Salmonella declined with compost storage. It was concluded that all composted biosolids had a Salmonella regrowth potential. However, the indigenous microflora significantly reduced this regrowth potential. Long-term storage of compost is not recommended as this may increase the pathogen regrowth potential.
Publisher: Elsevier BV
Date: 1985
Publisher: IWA Publishing
Date: 1995
Publisher: American Chemical Society (ACS)
Date: 13-12-2011
DOI: 10.1021/ES102482J
Abstract: A novel membraneless bioelectrochemical system termed rotatable bioelectrochemical contactor (RBEC) was fabricated and evaluated for its ability to recover useful energy (here methane) from a low organic strength wastewater. We studied the operational characteristics of the RBEC by operating it as a three-electrode electrolysis cell. A stack of conductive disks (each sub ided into two half disks), similar to rotating biological contactors, were rotated with one-half disk immersed in the wastewater and the other into the gas headspace. By carrying out regular half rotations (180° rotation) the anode became the cathode and vice versa. This operation resulted in the build-up of a biofilm that could catalyze both an anodic acetate oxidation and a cathode-driven methanogenesis. Methane production rate was directly proportional to the applied electrical energy. Increase in current density (from 0.16 to 4.1 A m(-2)) resulted in a faster COD removal (from 0.2 to 1.38 kg COD m(-3) day(-1)) and methane production (from 0.04 to 0.53 L L(-1) day(-1)). Of the electrons flowing across the circuit, over 80% were recovered as methane. Such methane production was electrochemically driven by the headspace-exposed cathodic half disks, which released the methane directly to the gas-phase. Energy analysis shows that the new design requires less energy for COD removal than what is typically required for oxygen supply in activated sludge processes. Because the system could operate without wastewater recirculation against gravity additional pH buffer chemicals ion-exchange membranes or electrochemical catalysts, it has desirable characteristics for process up-scale. Further, the current report shows the first ex le of a BES with identical biofilm (due to intermittent polarity inversion) on both electrodes.
Publisher: Oxford University Press (OUP)
Date: 11-1999
DOI: 10.1046/J.1365-2672.1999.00626.X
Abstract: In order to select a suitable indicator for monitoring the pathogen regrowth potential of composted biosolids, the growth kinetics of selected bacteria were investigated. Growth parameters of six serovars of Salmonella and three strains of Escherichia coli in sterilized compost were compared. Seeded Salmonella and E. coli grew rapidly, reaching population densities of more than 10(8) g-1 after 30 h of incubation. The specific growth rates of Salmonella serovars and E. coli strains were similar and varied from 0.49 to 0.55 h-1. The specific growth rate of the Salm. Typhimurium isolates was significantly higher than the other bacterial strains. It was concluded that an antibiotic-resistant strain of Salm. Typhimurium can be used as an indicator for a pathogen regrowth potential test.
Publisher: Informa UK Limited
Date: 18-07-2015
Publisher: IWA Publishing
Date: 1996
Publisher: Elsevier BV
Date: 09-2016
Publisher: IWA Publishing
Date: 05-1991
Abstract: The potential usage of Evapotranspiration (ET) systems in remote Aboriginal communities was investigated. ET system sizing requirements were determined from the water balance equation. Water loss from lysimeters planted with trees (Eucalyptus camaldulensis) or lawn grass and from bare soil and gravel was monitored over several months and compared to pan evaporation measured during the same period. It was found that ET from bare soil and grass followed similar trends to pan evaporation, ranging from 30-60% of pan evaporation for soil and from 60-80% of pan evaporation for grass. ET rates increased in the tanks planted with trees as the plants grew and exceeded pan evaporation rates. Evaporation from gravel-filled lysimeters was low, being as little as 10% of pan evaporation.
Publisher: IWA Publishing
Date: 1991
Abstract: North Lake is an urban freshwater wetland, and like other wetlands in the Perth metropolitan region, Western Australia, has become nutrient enriched, with the accompanying problems of algal blooms, decay, odour, infestation with midges and aesthetic deterioration. A study of the water quality of the lake was undertaken to quantify the variation of phosphorus, nitrogen and chlorophyll-a, and the sediments store of nutrients and their release with pH. The dominant algae in the lake, Microcystis, was found to be limited in growth by nitrogen because of the high availability of phosphorus (& 0.1 mg/l), and likely by light because of self-shading (chlorophyll-a & 0.3 mg/l). Sediments released a substantial amount of nutrients as pH rose above 8.5. Together with a parallel study of the nutrient budget of the lake, a management strategy has been derived to overcome the problem of nutrient enrichment that could be applied to other wetlands in the metropolitan region.
Publisher: Elsevier BV
Date: 03-1992
Publisher: IWA Publishing
Date: 1996
Publisher: IWA Publishing
Date: 1995
Publisher: Elsevier BV
Date: 2017
DOI: 10.1016/J.BIOS.2016.08.091
Abstract: Microbial biofilms are significant ecosystems where the existence of redox gradients drive electron transfer often via soluble electron mediators. This study describes the use of two interfacing working electrodes (WEs) to simulate redox gradients within close proximity (250µm) for the detection and quantification of electron mediators. By using a common counter and reference electrode, the potentials of the two WEs were independently controlled to maintain a suitable "voltage window", which enabled simultaneous oxidation and reduction of electron mediators as evidenced by the concurrent anodic and cathodic currents, respectively. To validate the method, the electrochemical properties of different mediators (hexacyanoferrate, HCF, riboflavin, RF) were characterized by stepwise shifting the "voltage window" (ranging between 25 and 200mV) within a range of potentials after steady equilibrium current of both WEs was established. The resulting differences in electrical currents between the two WEs were recorded across a defined potential spectrum (between -1V and +0.5V vs. Ag/AgCl). Results indicated that the technique enabled identification (by the distinct peak locations at the potential scale) and quantification (by the peak of current) of the mediators for in idual species as well as in an aqueous mixture. It enabled a precise determination of mid-potentials of the externally added mediators (HCF, RF) and mediators produced by pyocyanin-producing Pseudomonas aeruginosa (WACC 91) culture. The twin working electrode described is particularly suitable for studying mediator-dependent microbial electron transfer processes or simulating redox gradients as they exist in microbial biofilms.
Publisher: AIP Publishing
Date: 11-2012
DOI: 10.1063/1.4764935
Abstract: Despite the increasing number of small scale digesters operating, there remains a lack of information with regards to performance optimization from an everyday user's standpoint. The objective of this study was to determine the effects of volumetric dilution and food waste composition on digester performance. Batch experiments utilizing food waste majoring in carbohydrate, protein, lipid, and cellulose, subjected to five concentrations of volumetric dilution (3.7%–17.1% total solids (TS)), were conducted. Irregardless of volumetric dilution, all assays achieved substrate degradation higher than 82.5% and did not suffer methanogenic inhibition, when provided with retention times comparable to those used in small scale digesters. Protein rich and cellulose rich waste achieved the highest methane potential varying between 0.410–0.539 m3/kg volatile solids (VS) and 0.450–0.535 m3/kg VS, respectively. Protein rich assays were also observed to be the first to achieve 50% of its Bo irregardless of concentrations, followed by carbohydrates and cellulose, and lipids having a considerably longer methanation time. Results saw an increase in total methane generated but a decrease in specific yield as % total solid increased. To successfully digest lipid rich waste a dilution no lesser than 1:4 was required.
Publisher: Elsevier BV
Date: 10-1997
Publisher: Elsevier BV
Date: 07-2012
Publisher: Elsevier BV
Date: 09-2012
DOI: 10.1016/J.WATRES.2012.05.016
Abstract: High free ammonia released during anaerobic digestion of livestock wastes is widely known to inhibit methanogenic microorganisms and result in low methane production. This was encountered during our earlier thermophilic semi-continuously fed continuously-stirred tank reactor (CSTR) treatment of piggery wastewater. This study explored chemical and biological means to mitigate ammonia inhibition on thermophilic anaerobic treatment of piggery wastewater with the aim to increase organic volatile carbon reduction and methane production. A series of thermophilic anaerobic batch experiments were conducted on the digested piggery effluent to investigate the effects of pH reduction (pH 8.3 to 7.5, 7.0 and 6.5) and additions of biomass (10% v/v and 19% v/v anaerobic digested piggery biomass and aerobic-anaerobic digested municipal biomass), natural zeolite (10, 15 and 20 g/L) and humic acid (1, 5 and 10 g/L) on methane production at 55 °C for 9-11 days. Reduction of the wastewater pH from its initial pH of 8.3 to 6.5 produced the greatest stimulation of methane production (3.4 fold) coupled with reductions in free ammonia (38 fold) and total volatile fatty acids (58% TVFA), particularly acetate and propionate. Addition of 10-20 g/L zeolite to piggery wastewater with and without pH reduction to 6.5 further enhanced total VFA reduction and methane production over their respective controls, with 20 g/L zeolite producing the highest enhancement effect despite the ammonia-nitrogen concentrations of the treated wastewaters remaining high. Without pH reduction, zeolite concentration up to 20 g/L was required to achieve comparable methane enhancement as the pH-reduced wastewater at pH 6.5. Although biomass (10% v/v piggery and municipal wastes) and low humic acid (1 and 5 g/L) additions enhanced total VFA reduction and methane production, they elevated the residual effluent total COD concentrations over the control wastewaters (pH-unadjusted and pH-reduced) unlike zeolite treatment. The outcomes from these batch experiments support the use of pH reduction to 6.5 and zeolite treatment (10-20 g/L) as effective strategies to mitigate ammonia inhibition of the thermophilic anaerobic treatment of piggery wastewater.
Publisher: Elsevier
Date: 2019
Publisher: IWA Publishing
Date: 04-2000
Abstract: The Oil From Sludge (Enersludge™) process converts sewage sludge into hydrocarbons, partially fixing heavy metals in the by-product ash. Research was carried out to investigate the speciation and leaching behaviour of heavy metals (cadmium, copper, chromium, nickel, lead and zinc) when using this ash product in concrete. This was achieved by conducting a sequential extraction procedure, a soluble fraction test and dynamic leach test. Sequentialextraction showed that heavy metals in the ash speciated mainly into a stable form. Leachable heavy metals were derived mainly from the concrete (control s les). The soluble fraction test and the dynamic leach test indicated that heavy metals from concrete with Oil From Sludge ash addition exhibited a low leachability.
Publisher: Springer Science and Business Media LLC
Date: 11-02-2022
DOI: 10.1007/S43615-022-00153-1
Abstract: We observe that some industrial areas thrive, whilst others under-perform, and that the competitive potential of an enterprise located within an industrial area is impacted by a range of non-apparent characteristics related to the particular location. A dynamic industrial area is a better place for an industrial enterprise to be located than one that on the face of it seems lack-lustre—the ‘dynamism’ of the industrial area seems not that well understood or described. The goal of the literature review was to determine to what extent researchers have gone beyond the traditional view that industrial symbiosis (IS) is singularly focused on the symbiotic relationships that are responsible for the beneficial outcomes associated with product, by-product, and utility exchanges. We attempted to expose other forms of symbiotic relationships that might also contribute to the improved economic outcomes of companies located within complex industrial areas. Our findings confirm there are additional interacting factors contributing to the relative success (dynamism) of a given complex industrial area. We posit that an industrial area will exhibit varying degrees of success or failure, depending on the extent to which its creators have given thought to how it will operate to contribute to the international competitive advantages of its industrial inhabitants. We identified four contributing factors that contribute to this dynamism, and these align with an emerging four-dimensional framework for IS which the author is describing as the KIC4 dimensions of industrial symbiosis.
Publisher: Wiley
Date: 05-1967
Publisher: EDP Sciences
Date: 2023
DOI: 10.1051/REES/2023009
Abstract: Bioelectrochemical systems (BESs) can be integrated in situ into anaerobic digesters for increasing methane (CH 4 ) content of biogas. Using BES ex situ for improving biogas quality has recently been gaining attention. However, information on the process under thermophilic conditions is very limited. In this study, we placed a BES cathode in-line at the exit gas from a thermophilic anaerobic digester to convert carbon dioxide (CO 2 ) in the biogas into CH 4 . The performance of the ex situ BES reactor under thermophilic conditions was evaluated. When poising the cathode at −1.1 V versus Ag/AgCl in the ex situ BES reactor, CH 4 content increased from 50% to 85%. Of the incoming CO 2 73% was biologically converted to CH 4 and 23% absorbed by alkalinity generated in the cathode. The energy output as additional CH 4 as a percentage of the energy input to operate the BES was calculated at 56%. The biocathode of the BES reactor was dominated by Methanothermobacter spp., which are thermophilic hydrogen consuming methanogens. This study confirms that thermophilic BES can be used as an ex situ treatment process for enriching the CH 4 content of biogas. However, energy efficiency of the process was found to be limited by the lack of an energetically efficient anodic reaction. For industrial applications, optimisation of energy efficiency is an area for further research.
Publisher: SAGE Publications
Date: 05-1993
DOI: 10.1177/0734242X9301100306
Abstract: The disposal of fine bauxite refining residue (red mud) has occupied huge areas of land which remain derelict and subject to wind and water erosion. The major constraints in rehabilitation are the high alkalinity, salinity and sodicity of red mud. This paper describes a greenhouse study to evaluate the use of waste gypsum as ameliorants for red mud. Red mud was amended with gypsum at 0, 2, 5 and 8% (w/w) and its effect on the growth of two grass species, Agropyron elongatum (Tall wheat grass) and Cynodon dactylon (Bermuda grass), was evaluated. Gypsum amendment significantly reduced the pH, electrical conductivity (EC), and Na and Al content of red mud and provided a continuous supply of Ca 2+ , which resulted in a lower soil exchangeable sodium percentage (ESP). The improved soil conditions at ≥ 5% gypsum amendment significantly increased seedling emergence and dry weight yields. The enhanced plant growth and seedling emergence show significant negative correlations with pH, Al and ESP of soil. Tissue analyses indicated that the availability of P, K, Mg and Ca also increased for ≥ 5% gypsum amended red mud, while Na and Fe were less available. Results from the present study indicated that waste gypsum is an effective ameliorant for red mud revegetation and no topsoil amendment is required.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 11-1991
Publisher: Wiley
Date: 23-09-2014
DOI: 10.1111/NPH.13030
Abstract: In wheat stems, the levels of fructan‐dominated water‐soluble carbohydrates ( WSC ) do not always correlate well with grain yield. Field drought experiments were carried out to further explain this lack of correlation. Wheat ( Triticum aestivum ) varieties, Westonia, Kauz and c . 20 genetically erse double haploid ( DH ) lines derived from them were investigated. Substantial genotypic differences in fructan remobilization were found and the 1‐ FEH w3 gene was shown to be the major contributor in the stem fructan remobilization process based on enzyme activity and gene expression results. A single nucleotide polymorphism ( SNP ) was detected in an auxin response element in the 1‐ FEH w3 promoter region, therefore we speculated that the mutated Westonia allele might affect gene expression and enzyme activity levels. A cleaved lified polymorphic ( CAP ) marker was generated from the SNP . The harvested results showed that the mutated Westonia 1‐ FEH w3 allele was associated with a higher thousand grain weight ( TGW ) under drought conditions in 2011 and 2012. These results indicated that higher gene expression of 1‐ FEH w3 and 1‐ FEH w3 mediated enzyme activities that favoured stem WSC remobilization to the grains. The CAP marker residing in the 1‐ FEH w3 promoter region may facilitate wheat breeding by selecting lines with high stem fructan remobilization capacity under terminal drought.
Publisher: Elsevier BV
Date: 02-2019
Publisher: Informa UK Limited
Date: 02-2013
DOI: 10.1080/09593330.2012.701236
Abstract: The production of crude cellulase in solid-state fermentation was simplified by using environmental selection pressures as an alternative to specialized strains and by re-using cellulose-to-ethanol fermentation substrate for cellulase production. The performance of wild strains of Trichoderma viride isolated from wheat and bark were found not to differ significantly from a 'cellulase-enhanced' strain of Trichoderma reesei. The filter paper activity of a strain of Aspergillus niger isolated in the laboratory was more than two times higher than the specialized T. reesei at 10 days. Activities of enrichment cultures obtained from compost and horse manure were more than double T. reesei after 10 days. Using the solid residue of previous simultaneous saccharification and fermentations of wheat straw to ethanol as substrate for cellulase production brought forward the onset of cellulase production and increased cellulase levels by 50%. The findings may help to simplify the on-site manufacture of cellulase for cellulose-to-ethanol conversion and reduce the amount of substrate required for the overall process.
Publisher: Elsevier BV
Date: 08-2012
DOI: 10.1016/J.BIORTECH.2012.04.082
Abstract: This study aims to investigate thermophilic methanogens in turf used as an inoculum. Results showed that Methanoculleus sp. regarded as hydrogenotrophic and Methanosarcina sp. regarded as acetoclastic methanogens were present in turf tested. However, active acetoclastic methanogens were present in turf soil only. The current study showed that thermophilic methanogens were present in various turf grass species: Stenotaphrum secundatum, Cynodon dactylon, and Zoysia japonica. Severe treatments of grass leaves under oxic conditions, including blending, drying and pulverizing did not affect the thermophilic hydrogenotrophic methanogenic activity of the grass. A dried and pulverized grass extract could be generated that can serve as a readily storable methanogenic inoculum for thermophilic anaerobic digestion. The methanogens could also be physically extracted into an aqueous suspension, suitable as an inoculum. The possible contribution of the presence of methanogens on grass plants to global greenhouse emissions is briefly discussed.
Publisher: Oxford University Press (OUP)
Date: 30-05-2017
DOI: 10.1111/LAM.12747
Abstract: Control of biofouling on seawater reverse osmosis (SWRO) membranes is a major challenge as treatments can be expensive, damage the membrane material and often biocides do not remove the polymers in which bacteria are embedded. Biological control has been largely ignored for biofouling control. The objective of this study was to demonstrate the effectiveness of xanthine oxidase enzyme against complex fouling communities and then identify naturally occurring bacterial strains that produce the free radical generating enzyme. Initially, 64 bacterial strains were isolated from different locations of the Perth Seawater Desalination Plant. In our preceding study, 25/64 isolates were selected from the culture collection as models for biofouling studies, based on their prevalence in comparison to the genomic bacterial community. In this study, screening of these model strains was performed using a nitroblue tetrazolium assay in the presence of hypoxanthine as substrate. Enzyme activity was measured by absorbance. Nine of 25 strains tested positive for xanthine oxidase production, of which Exiguobacterium from sand filters and Microbacterium from RO membranes exhibited significant levels of enzyme production. Other genera that produced xanthine oxidase were Marinomonas, Pseudomonas, Bacillus, Pseudoalteromonas and Staphylococcus. Strain variations were observed between members of the genera Microbacterium and Bacillus. Xanthine oxidase, an oxidoreductase enzyme that generates reactive oxygen species, is endogenously produced by many bacterial species. In this study, production of the enzyme by bacterial isolates from a full-scale desalination plant was investigated for potential use as biological control of membrane fouling in seawater desalination. We have previously demonstrated that free radicals generated by a commercially available xanthine oxidase in the presence of a hypoxanthine substrate, effectively dispersed biofilm polysaccharides on industrially fouled membranes. Bacterial xanthine oxidase production in the presence of hypoxanthine may prove to be a cost effective, in situ method for alleviation of fouling.
Publisher: Elsevier BV
Date: 08-1994
Publisher: Elsevier
Date: 2017
No related grants have been discovered for Goen Ho.