ORCID Profile
0000-0003-1175-5161
Current Organisations
Monash University
,
University of South Australia
,
Hawthorn Institute of Education
,
Royal Melbourne Institute of Technology
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Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D2EW00389A
Abstract: A continuous floc image analyser (C-FIA) was developed for tracking the dynamics of floc particle formation, growth and settling during conventional water treatment. This is based on a new RGB signal for flocculation index determination.
Publisher: Springer Science and Business Media LLC
Date: 09-03-2022
Publisher: Elsevier BV
Date: 10-2015
DOI: 10.1016/J.SCITOTENV.2015.05.037
Abstract: The influence of vegetation and soil texture on the concentration and character of dissolved organic matter (DOM) present in runoff from the surface and sub-surface of zero order catchments of the Myponga Reservoir-catchment (South Australia) was investigated to determine the impacts of catchment characteristics and land management practices on the quality of waters used for domestic supply. Catchments selected have distinct vegetative cover (grass, native vegetation or pine) and contrasting texture of the surface soil horizon (sand or clay loam/clay). Water s les were collected from three slope positions (upper, middle, and lower) at soil depths of ~30 cm and ~60 cm in addition to overland flows. Filtered (0.45 μm) water s les were analyzed for dissolved organic carbon (DOC) and UV-visible absorbance and by F-EEM and HPSEC with UV and fluorescence detection to characterize the DOM. Surface and sub-surface runoff from catchments with clay soils and native vegetation or grass had lower DOC concentrations and lower relative abundances of aromatic, humic-like and high molecular weight organics than runoff from sandy soils with these vegetative types. Sub-surface flows from two catchments with Pinus radiata had similar DOC concentrations and DOM character, regardless of marked variation in surface soil texture. Runoff from catchments under native vegetation and grass on clay soils resulted in lower DOC concentrations and hence would be expected to have lower coagulant demand in conventional treatment for potable water supply than runoff from corresponding sandy soil catchments. However, organics in runoff from clay catchments would be more difficult to remove by coagulation. Surface waters from the native vegetation and grass catchments were generally found to have higher relative abundance of organic compounds amenable to removal by coagulation compared with sub-surface waters. Biophysical and land management practices combine to have a marked influence on the quality of source water used for domestic supply.
Publisher: Springer Science and Business Media LLC
Date: 07-01-2012
DOI: 10.1007/S11356-011-0714-Y
Abstract: The characteristics of organics in sulphite pulp mill effluent and in the receiving environment of effluent discharge were investigated to assess the basis for the persistence or attenuation of colour. Characterization of organics was conducted through determination of SUVA, specific colour, and molecular weight distribution of organics using high performance size exclusion chromatography and by solid-state (13) C cross polarization (CP) NMR. The characteristics of organics from mill wastewater before and after secondary aerobic treatment, followed by lime treatment and from the receiving environment, an enclosed brackish lake were compared. Changes in the character of organics in lake water over a period of 14 years were studied in the context of changes in mill processing and climate impacts. High colour in mill effluent and in receiving waters correlated with high SUVA and specific colour levels, high molecular weight range and aromatic content. Conversely, lake waters with low colour had UV absorbing compounds of much lower molecular weight range and low relative abundance of aromatic compounds. Attenuation of colour and changes in the character of organics in the receiving environment coincided with increased concentrations of metal cations. These increased concentrations appear to be due to the effects of climate change, lake management and their presence in mill effluent, with subsequent discharge to the lake. Attenuation of colour was found to be predominantly through removal of high molecular weight aromatic compounds where the removal processes could be through adsorption and co-precipitation with alent metals, as well as through dilution processes.
Publisher: Elsevier BV
Date: 07-2012
DOI: 10.1016/S1001-0742(11)60923-6
Abstract: High performance size exclusion chromatography (HPSEC) is used in water quality research primarily to determine the molecular weight distribution of the dissolved organic matter (DOM), but by applying peak fitting to the chromatogram, this technique can also be used as a tool to model and predict DOM removal. Six low specific UV absorbance (SUVA) source waters were treated using coagulation with alum and both the source and treated water s les were analysed using HPSEC. By comparing the molecular weight profiles of the source and treated waters, it was established that several DOM components were not effectively removed by alum coagulation even after high dosage alum treatment. A peak-fitting technique was applied based on the concept of linking the character (molecular weight profile) of the recalcitrant organics in the treated water with those of the source water. This was then applied to predict DOM treatability by determining the areas of the peaks which were assigned to removable organics from the source water molecular weight profile after peak fitting, and this technique quantified the removable and non-removable organics. The prediction was compared with the actual dissolved organic carbon (DOC) removal determined from jar testing and showed good agreement, with variance between 2% and 10%. This confirmed that this prediction approach, which was originally developed for high SUVA waters, can also be applied successfully to predict DOC removal in low SUVA waters.
Publisher: Elsevier BV
Date: 04-2011
Publisher: Elsevier BV
Date: 11-2011
Publisher: IWA Publishing
Date: 30-09-2014
DOI: 10.2166/WS.2013.199
Abstract: In recent climatic events in Australia, the need for frequent jar testing to determine optimum coagulant and flocculant aid doses became apparent in order to determine optimum treatment efficiencies. The generally applied jar test procedure can be time consuming and this prompted investigations for capacity to test waters more rapidly, for a range of treatment conditions and raw water qualities. The aim of the study reported here was to develop a rapid procedure for determination of dissolved organic matter (DOM) removal, measured as dissolved organic carbon (DOC) and UV absorbance (254 nm/cm) for a range of treatment conditions (coagulant dose and pH). Using a previously established predictive model (mEnCo) for coagulant determination, several coagulant doses were then predicted for application in a modified jar test protocol. Best fitted and predicted data using the exponential decay function compared with data from a 6× jar test procedure were obtained using three doses, 0.5× EnCD, EnCD and a VHD (≥2× EnCD). It is proposed that this procedure may be used to more rapidly determine treatment efficiency based on the removal of organics compared with traditionally applied jar tests.
Publisher: Elsevier BV
Date: 07-2016
DOI: 10.1016/J.JES.2017.01.006
Abstract: Minimizing particles in water is a key goal for improving drinking water quality and safety. The media filtration process, as the last step of the solid-liquid separation process, is largely influenced by the characteristics of flocs, which are formed and controlled within the coagulation process. In a laboratory-based study, the impacts of the physical characteristics of flocs formed using aluminum sulfate on the filtration treatment of two comparative water s les were investigated using a photometric dispersion analyzer and a filterability apparatus. In general, the optimum dosage for maximizing filterability was higher than that for minimizing turbidity under neutral pH conditions. For a monomeric aluminum-based coagulant, the charge neutralization mechanism produced better floc characteristics, including floc growth speed and size, than the sweep flocculation mechanism. In addition, the charge neutralization mechanism showed better performance compared to sweep flocculation in terms of DOC removal and floc filterability improvement for both waters, and showed superiority in turbidity removal only when the raw water had high turbidity. For the different mechanisms, the ways that floc characteristics impacted on floc filterability also differed. The low variation in floc size distribution obtained under the charge neutralization mechanism resulted in the flocs being amenable to removal by filtration processes. For the sweep flocculation mechanism, increasing the floc size improved the settling ability of flocs, resulting in higher filter efficiency.
Publisher: Elsevier BV
Date: 05-2012
DOI: 10.1016/J.JHAZMAT.2012.02.039
Abstract: The adsorption of natural organic matter (NOM) from eight typical Chinese surface waters onto alumina was investigated using quartz crystal microbalance with dissipation monitoring (QCM-D). The adsorbed masses of NOM varied between 25ngcm(-2) and 64ngcm(-2), and these showed significant correlation with geographical location, and NOM character and concentrations. Adsorbed mass correlated with DOC concentration (slope k=0.0676, R(2)=0.61) and hydrophobic acid (HoA) and weakly hydrophobic acid (WHoA) (k=0.0342 and 0.0183 R(2)=0.49 and 0.52 for HoA and WHoA, respectively) constituents present in the water s les. The process of adsorbed layer formation was investigated from changes in the ΔD/Δf ratio and viscosity of adsorbed layer with injected time. The adsorbed layer viscosity increased exponentially with injected time (R(2)>0.99) for most s les. S les with low DOC concentration (k=-1091.8, R(2)=0.55) and low content of HoA and WHoA (k=-524.33 and -322.76 R(2)=0.41 and 0.64 for HoA and WHoA, respectively), the slope of logarithm viscosity value is steeper, the property of adsorbed layer and NOM is more inconsistent. The QCM-D technique provides a method to view the process of complexation between NOM and coagulant, and can provide useful information to establish a quantitative calculation model of the coagulation process.
Publisher: Elsevier BV
Date: 11-2002
DOI: 10.1016/S0043-1354(02)00218-X
Abstract: Waters from five reservoirs and "synthetic waters", prepared using terrestrially derived dissolved organic matter (DOM) extracted from vegetation and reservoir catchment soils, were studied for their treatability with alum using a jar test procedure. DOM in drinking water is a precursor for the formation of trihalomethanes (THM) following chlorine disinfection and can also be a substrate for microbial growth in the drinking water distribution system. The trihalomethane formation potential (THMFP) represents an upper concentration limit on THMs formed by chlorination, while bacterial regrowth potential (BRP) is an indicator of the bioavailability of DOM. BRP and THMFP were measured before and after alum treatment and the results were related to the source of the DOM. It was found that freshly derived terrestrial DOM in synthetic water resulted in higher THMFP and BRP than DOM in reservoir waters. For the s les investigated, conventional alum treatment did not always reduce the THM precursor levels formed in laboratory tests below the NH&MRC (1996) guideline level of 250 microg/L nor produce microbially stable waters.
Publisher: Elsevier BV
Date: 05-2016
DOI: 10.1016/J.JHAZMAT.2016.01.030
Abstract: Dissolved organic matter (DOM) in surface waters used for drinking purposes can vary markedly in character dependent on their sources within catchments. The character of DOM further influences the formation of disinfection by products when precursor DOM present in drinking water reacts with chlorine during disinfection. Here we report the development of models that describe the formation potential of trihalomethanes (THMFP) dependent on the character of DOM in waters from discrete catchments with specific land-use and soil textures. DOM was characterized based on UV absorbance at 254 nm, apparent molecular weight and relative abundances of protein-like and humic-like compounds. DOM character and Br concentration (up to 0.5 mg/L) were used as variables in models (R(2)>0.93) of THMFP, which ranged from 19 to 649 μg/L. Chloroform concentration (12-594 μg/L) and relative abundance (27-99%) were first modeled (R(2)>0.85) and from these, the abundances of bromodichloromethane and chlorodibromomethane estimated using power and exponential functions, respectively (R(2)>0.98). From these, the abundance of bromoform is calculated. The proposed model may be used in risk assessment of catchment factors on formation of trihalomethanes in drinking water, in context of treatment efficiency for removal of organic matter.
Publisher: Bentham Science Publishers Ltd.
Date: 31-12-2013
Publisher: Thomas Telford Ltd.
Date: 07-2011
DOI: 10.1680/WAMA.2011.164.7.361
Abstract: The harvesting, storage and reuse of stormwater from permeable pavement reservoirs provides an opportunity to alleviate water shortages in urban areas. Reservoirs may be filled with a range of basecourse aggregate materials that provide structural support to the pavement. The materials have the potential to affect the quality of stored water. This research investigated changes in water quality when water was stored in two types of basecourse aggregate. Synthetic stormwater was placed in permeable pavement reservoir models filled with dolomite aggregate or quartzite aggregate or control reservoirs with no aggregate. The influence of residence time was investigated by monitoring stored water quality for up to 144 h. Conductivity and pH increased in both aggregate-filled reservoirs. Total suspended solids and turbidity also increased in the aggregate-filled reservoirs, before falling to levels significantly lower than the control reservoirs. Levels of phosphorous and organic nitrogen were significantly lower in the aggregate-filled reservoirs after 144 h. Total zinc, copper and lead were reduced by 94–99% in the aggregate-filled reservoirs compared with the controls after 144 h storage.
Publisher: Elsevier BV
Date: 12-2013
Publisher: Elsevier BV
Date: 04-2000
Publisher: IWA Publishing
Date: 10-2008
DOI: 10.2166/WST.2008.475
Abstract: Natural Organic Matter (NOM) from Myponga Reservoir, South Australia, was separated into four organic fractions based on their hydrophobic and hydrophilic properties using a sequence of non-ionic and ionic resins. NOM fractions were isolated for the purpose of determining the impact of alum coagulation on removal of these fractions in conventional water treatment, and their potential as precursors in the formation of disinfection by-products (DBP) and in supporting microbial growth. The NOM comprised VHA (very hydrophobic acids), SHA (slightly hydrophobic acids), CHA (charged hydrophilics) and NEU (neutral hydrophilics) fractions. These fractions were then jar tested with alum using low (50 mg/L), operational (100 mg/L) and very high (200 mg/L) doses to assess the removal capacities for these fractions in a conventional treatment plant. High-performance size exclusion chromatography-UV-DOC (HPSEC-UV-DOC) revealed that alum removed more of the hydrophobic and higher molecular weight components of NOM, but less of the NEU fraction and lower molecular weight components of NOM. Determination of biodegradable dissolved organic carbon (BDOC) indicated that the NEU fraction had the highest biodegradability, followed by the CHA, SHA and VHA fractions. The VHA fraction had the highest total-trihalomethane formation potential (t-THMFP), followed by NEU, SHA and CHA. The NOM not removed by alum coagulation had the potential to support microbial growth (NEU fraction), and disinfection by-product (DBP) formation (VHA and NEU fractions). To obtain treated water with lower overall residual NOM, other treatment methods would need to be applied in addition to alum coagulation in order to reduce the concentration of the neutral fraction.
Publisher: Informa UK Limited
Date: 10-2012
Publisher: Springer Science and Business Media LLC
Date: 15-08-2008
Publisher: Elsevier BV
Date: 08-2009
Publisher: Elsevier BV
Date: 09-2009
Publisher: Elsevier BV
Date: 06-2012
Publisher: Elsevier BV
Date: 07-2016
DOI: 10.1016/J.JES.2017.01.010
Abstract: A model is developed to enable estimation of chloramine demand in full scale drinking water supplies based on chemical and microbiological factors that affect chloramine decay rate via nonlinear regression analysis method. The model is based on organic character (specific ultraviolet absorbance (SUVA)) of the water s les and a laboratory measure of the microbiological (F
Publisher: Elsevier BV
Date: 12-2002
Publisher: CSIRO Publishing
Date: 1993
DOI: 10.1071/MF9930825
Abstract: Water and sediment s les from Lake Bonney (south-eastern South Australia) were collected at various distances from the effluent discharge point of a sulfite-based pulp mill and analysed for chlorophenolic compounds. The period of s le collection (July 1991 to January 1992) occurred during a time when bleaching process of the mill was being converted from using molecular chlorine to using hydrogen peroxide. In water s les, the major chlorophenolic compounds detected were 2,4,6-trichlorophenol, tetrachlorocatechol and chlorinated guaiacols. In sediment s les, the major chlorophenolic compounds detected were chlorinated guaiacols and chlorinated catechols. The concentrations of these compounds in lake water generally decreased over the s ling period, corresponding to the decrease in use of molecular chlorine. Concentrations in sediment decreased with increasing distance from the discharge point. The presence of chlorinated guaiacols in water and sediment at a site 17 km from the effluent discharge point indicated that these compounds degrade slowly in the lake. The presence of the chlorinated catechols in sediments at localities where these compounds were not detected in the water suggests that de-0-methylation of adsorbed chlorinated guaiacols occurs and/or that there is preferential adsorption of chlorinated catechols to sediment.
Publisher: Elsevier BV
Date: 05-2016
DOI: 10.1016/J.CHEMOSPHERE.2016.02.030
Abstract: In full scale water treatment operation, the rapid filtration process, as the last step of solid-liquid separation, is largely influenced by floc characteristics. In this study, aluminium sulphate (alum) and nano-Al13 were investigated to understand the influence of coagulant species on the formation and filterability of flocs. At neutral pH, it was found that nano-Al13, a high MW polymer, showed better floc filterability than alum. This is because of the densely compacted and well-distributed size flocs from nano-Al13, even though floc sizes of alum were generally bigger. Al specie distributions of the two coagulants at different pH levels were compared by using electrospray ionization time-of-flight mass spectrometry (ESI-TOF-MS) to further elucidate the reasons for the superiority of nano-Al13 in floc filterability. Depolymerisation/re-polymerisation of nano-Al13 occurred as pH changed, and Al species from nano-Al13were more abundant than that from alum, especially for the high molecular weight (MW) oligomers such as Al11, Al12, Al13 and Al14. Under the charge neutralisation mechanism, higher MW Al species was found to improve coagulation performance and floc filterability. In addition, breakage resistance and regrowth ability of nano-Al13 was better than alum, at weak acid condition. Flocs formed by the charge neutralisation mechanism readily regenerated after being thoroughly broken up. The floc regrowth ability of nano-Al13 at high shear rates (200 rpm and 300 rpm) was much better than at low shear and better than any shear applied to alum., and the flocs after breakage at 200 rpm and 300 rpm also showed better filterability than other conditions.
Publisher: Springer Science and Business Media LLC
Date: 04-12-2013
DOI: 10.1007/S11356-013-2351-0
Abstract: The paper-making process can produce large amounts of wastewater (WW) with high particulate and dissolved organic loads. Generally, in developed countries, stringent international regulations for environmental protection require pulp and paper mill WW to be treated to reduce the organic load prior to discharge into the receiving environment. This can be achieved by primary and secondary treatments involving both chemical and biological processes. These processes result in complex changes in the nature of the organic material, as some components are mineralised and others are transformed. In this study, changes in the nature of organics through different stages of secondary treatment of pulp and paper mill WW were followed using three advanced characterisation techniques: solid-state (13)C nuclear magnetic resonance (NMR) spectroscopy, pyrolysis-gas chromatography mass spectrometry (py-GCMS) and high-performance size-exclusion chromatography (HPSEC). Each technique provided a different perspective on the changes that occurred. To compare the different chemical perspectives in terms of the degree of similarity/difference between s les, we employed non-metric multidimensional scaling. Results indicate that NMR and HPSEC provided strongly correlated perspectives, with 86 % of the discrimination between the organic s les common to both techniques. Conversely, py-GCMS was found to provide a unique, and thus complementary, perspective.
Publisher: Informa UK Limited
Date: 04-2013
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D2EW00376G
Abstract: An optimized electrocoagulation process was investigated for enhanced removal of dissolved organic matter for eco-friendly drinking water production from surface water sources. A model-based control system was developed for electro-coagulant dosing.
Publisher: Elsevier BV
Date: 07-2016
DOI: 10.1016/J.JES.2016.11.007
Abstract: The management of chloramine decay and the prevention of nitrification are some of the critical issues faced by water utilities that use chloramine as a disinfectant. In this study, potential association between high performance size exclusion chromatography (HPSEC) data obtained with multiple wavelength Ultraviolet (UV) detection from two drinking water distribution systems in Australia and nitrification occurrence was investigated. An increase in the absorbance signal of HPSEC profiles with UV detection at λ=230nm between apparent molecular weights of 200 to 1000Da was observed at s ling sites that experienced rapid chloramine decay and nitrification while its absorbance signal at λ=254nm decreased. A chloramine decay index (C.D.I) defined as the ratio of area beneath the HPSEC spectra at two different wavelengths of 230 and 254nm, was used in assessing chloramine decay occurrences. The C.D.Is of waters at locations that experienced nitrification were consistently higher than locations not experiencing nitrification. A simulated laboratory study showed that the formation of nitrite/nitrate and/or soluble microbial products and/or the release of extracellular polymeric substances (EPS) during nitrification may contribute to the C.D.I. increase. These findings suggest that C.D.I derived from HPSEC with multiple wavelength UV detection could be an informative index to track the occurrence of rapid chloramine decay and nitrification.
Publisher: Elsevier BV
Date: 06-2013
Publisher: Elsevier BV
Date: 06-2005
Publisher: Elsevier BV
Date: 02-2012
DOI: 10.1016/S1001-0742(11)60717-1
Abstract: Correlations between raw water characteristics and pH after enhanced coagulation to maximize dissolved organic matter (DOM) removal using four typical coagulants (FeCl3, Al2(SO4)3, polyaluminum chloride (PACl) and high performance polyaluminum chloride (HPAC)) without pH control were investigated. These correlations were analyzed on the basis of the raw water quality and the chemical and physical fractionations of DOM of thirteen Chinese source waters over three seasons. It was found that the final pH after enhanced coagulation for each of the four coagulants was influenced by the content of removable DOM (i.e. hydrophobic and higher apparent molecular weight (AMW) DOM), the alkalinity and the initial pH of raw water. A set of feed-forward semi-empirical models relating the final pH after enhanced coagulation for each of the four coagulants with the raw water characteristics were developed and optimized based on correlation analysis. The established models were preliminarily validated for prediction purposes, and it was found that the deviation between the predicted data and actual data was low. This result demonstrated the potential for the application of these models in practical operation of drinking water treatment plants.
Publisher: Elsevier BV
Date: 08-2013
Publisher: Elsevier BV
Date: 10-2014
Publisher: Elsevier BV
Date: 10-2014
Publisher: IWA Publishing
Date: 02-2011
DOI: 10.2166/WST.2011.248
Abstract: The use of coagulation and flocculation for tertiary treatment of pulp and paper mill effluent was investigated, where the evaluation was based on the removal of nitrogen (N), phosphorus (P) and BOD from post-coagulated wastewater. The study was undertaken on laboratory scale aerobic stabilisation basins (ASB). Two post coagulated (alum) wastewaters were studied, where the BOD:N:P ratios were 100:1.3:0.06 and 100:1.3:0.3. These wastewaters were treated in two identical concurrent simulations (A & B). The influent ratio for ‘A’ was selected representing the composition of actual coagulated Pinus radiata sulfite pulp effluent mixed with paper mill effluent. The input composition for ‘B’ represented a typical P concentration found in existing pulp and paper mill effluents. Unmodified sludge collected from a mill-pond was added at 4% v/v to each simulation replicating the treatment conditions at full-scale. Similar high percentage removals of BOD and COD occurred after 28 days (two HRTs) which were 94 and 67% respectively for ‘A’, and 98 and 70% respectively for ‘B’, where both remained at steady state during the third HRT. A statistical analysis of the data revealed that there was no significant difference in the s le variance of the BOD and COD results.
Publisher: IWA Publishing
Date: 19-08-2021
Abstract: The bacterial regrowth potential (BRP) method was utilised to indirectly measure the assimilable organic carbon (AOC) as an indicator for the assessment of the microbial regrowth potential in drinking water distribution systems. A model using various microbial growth parameters was developed in order to standardise the experimental interpretation for BRP measurement. This study used 82 experimental BRP data sets of water s les collected from the water treatment plant to locations (customer taps) in the distribution system. The data were used to model the BRP process (growth curve) by a data fitting procedure and to obtain a best-fitted equation. Statistical assessment and validation of the model obtained equation by fitting these 82 sets of data were conducted, and the results show average R2 values were 0.987 for treated water s les (collected at the plant prior to chlorination) and 0.983 for tap water (collected at the customer taps). The F values obtained from the F-test are all exceeded their corresponding F critical values, and the results from the t-test also showed a good outcome. These results indicate this model would be successfully applied in modelling BRP in drinking water supply systems.
Publisher: Elsevier BV
Date: 10-2014
DOI: 10.1016/J.JES.2014.08.001
Abstract: The treatment of organics present in the lower reaches of a major river system (the Murray-Darling Basin, Australia) before (March-July 2010), during (December 2010-May 2011) and after (April-December 2012) a major flood period was investigated. The flood period (over 6months) occurred during an intense La Niña cycle, leading to rapid and high increases in river flows and organic loads in the river water. Dissolved organic carbon (DOC) increased (2-3 times) to high concentrations (up to 16mg/L) and was found to correlate with river flow rates. The treatability of organics was studied using conventional jar tests with alum and an enhanced coagulation model (mEnCo©). Predicted mean alum dose rates (per mg DOC) were higher before (9.1mg alum/mg DOC) and after (8.5mg alum/mg DOC) than during the flood event (8.0mg alum/mg DOC), indicating differences in the character of the organics in raw waters. To assess the character of natural organic matter present in raw and treated waters, high performance size exclusion chromatography with UV and fluorescence detectors were used. During the flood period, high molecular weight UV absorbing compounds (>2kDa) were mostly detected in waters collected, but were not evident in waters collected before and afterwards. The relative abundances of humic-like and protein-like compounds during and following the flood period were also investigated and found to be of a higher molecular weight during the flood period. The treatability of the organics was found to vary over the three climate conditions investigated.
Publisher: Elsevier BV
Date: 06-2023
Publisher: Elsevier BV
Date: 02-2016
DOI: 10.1016/J.CHEMOSPHERE.2015.09.066
Abstract: The treatability of NOM present in runoff and subsurface waters from discrete zero-order catchments (ZOCs) with three land management practices (Australian native vegetation, pine plantation, grasslands) on varying soil textures of a closed drinking water reservoir-catchment was investigated. Subsurface water s les were collected by lysimeters and shallow piezometers and surface waters by installation of barriers that erted waters to collection devices. For small s le volumes collected, a 'micro' jar testing procedure was developed to assess the treatability of organics by enhanced coagulation using alum, under standardised conditions. DOM present in water s les was quantified by measurement of DOC and UV absorbance (at 254 nm) and characterized using these and F-EEM. The mean alum dose rate (mg alum per mg DOC removed or Al/DOC) was found to be lower for DOM from sandy soil ZOCs (21.1 ± 11.0 Al/DOC) than from clayey soil ZOCs (38.6 ± 27.7 Al/DOC). ZOCs with Pinus radiata had prominent litter layers (6.3 ± 2.6 cm), and despite differences in soil textures showed similarity in DOM character in subsurface waters, and in alum dose rates (22.2 ± 5.5 Al/DOC). For sandy soil ZOCs, the lowest alum dose rates (16.5 ± 10.6 Al/DOC) were for waters from native vegetation catchment while, for clayey soil ZOCs, waters from pine vegetation had the lowest alum dose rates (23.0 ± 5.0 Al/DOC). Where ZOCs have a prominent O horizon, soil minerals had no apparent influence on the treatability of DOM.
Publisher: Elsevier BV
Date: 04-2011
Publisher: CSIRO Publishing
Date: 2001
DOI: 10.1071/MF00058
Abstract: Conventional pyrolysis—GC—MS,thermochemolysis and alkaline CuO oxidation were applied to determine differences between dissolved organic matter (DOM)from terrestrial plants,soil horizons and drinking water reservoirs in two catchments in South Australia.These two reservoir-catchment systems were selected on the basis of contrasting vegetation and land use.Pyrolysis of DOM yielded furans,aliphatic products and N-containing compounds,which are indicative of polysaccharides,lipids and proteins,respectively.Thermo-chemolysis enabled detection of methoxy-benzyl compounds derived from various sources of DOM,indicating that these compounds can be used as bio-markers of vascular plant sources.Vanillic acid was detected from DOM isolates from the vegetation,soils and reservoir waters of the two catchments,using CuO oxidation,and hence this compound also appears to be a suitable bio-marker for tracing allochthonous DOM input into the reservoirs. Each of the three techniques resulted in the formation of different compounds from the DOM isolates,which indicated the type of precursor bio-polymer and/or some of the methoxyphenol structures of lignin.
Publisher: Elsevier BV
Date: 06-2013
Publisher: IWA Publishing
Date: 06-2009
Publisher: Elsevier BV
Date: 2017
DOI: 10.1016/J.ENVPOL.2016.10.054
Abstract: Dissolved organic matter (DOM) in surface waters used for drinking purposes can vary markedly in character depending on its source within catchments and the timing and intensity of rainfall events. Here we report the findings of a study on the character and concentration of DOM in waters collected during different seasons from Myponga River and Reservoir, South Australia. The character of DOM was assessed in terms of its treatability by enhanced coagulation and potential for disinfection by-product i.e. trihalomethane (THM) formation. During the wet seasons (winter and spring), water s les from the river had higher DOC concentrations (X¯: 21 mg/L) and DOM of higher average molecular weight (AMW: 1526 Da) than waters collected during the dry seasons (summer and autumn: DOC: 13 mg/L AMW: 1385 Da). Even though these features led to an increase in the percentage removal of organics by coagulation with alum (64% for wet compared with 53% for dry season s les) and a lower alum dose rate (10 versus 15 mg alum/mg DOC removal), there was a higher THM formation potential (THMFP) from wet season waters (treated waters: 217 μg/L vs 172 μg/L). For reservoir waters, s les collected during the wet seasons had an average DOC concentration (X¯: 15 mg/L), percentage removal of organics by alum (54%), alum dose rates (13 mg/mg DOC) and THMFP (treated waters: 207 μg/L) that were similar to s les collected during the dry seasons (mean DOC: 15 mg/L removal of organics: 52% alum dose rate: 13 mg/mg DOC THMFP: 212 μg/L for treated waters). These results show that DOM present in river waters and treatability by alum are highly impacted by seasonal environmental variations. However these in reservoir waters exhibit less seasonal variability. Storage of large volumes of water in the reservoir enables mixing of influent waters and stabilization of water quality.
Publisher: IWA Publishing
Date: 02-2013
DOI: 10.2166/WS.2012.095
Abstract: The dissolved organic matter (DOM) plays significant role in water safety due to not only the natural occurrence but also man-induced pollution. To characterize and predict DOM treatability becomes therefore a very important and hot topic. In this paper, enhanced coagulation by four typical coagulants (FeCl3, Al2(SO4)3, polyaluminum chloride (PAC) and high performance polyaluminum chloride (HPAC)) without pH control was characterized using the chemical fractionation (resin adsorption, RA) and physical fractionation (high performance size exclusion chromatography (HPSEC) combined with peak fitting technique). The results show that the DOM removal can be separated into two stages, rapid removal and continual slow removal. The PAC exhibits efficient removal in the rapid part while the traditional salts are more efficient in the latter part. It is also very important for pH control to improve DOM removal by the traditional coagulants. DOM treatability per unit dosage (1 × 10−4 mol/l) for the four coagulants was then calculated in the order of HPAC (26.0%) & PAC (17.3%) & FeCl3 (14.3%) & Al2(SO4)3 (12.0%). Two sets of DOM treatability models, i.e. removal efficiency, for enhanced coagulation of the four coagulants were developed by combining the chemical and physical DOM fractions based on the quantitative analysis of the removal state of raw water. The two sets of models could be transformed to each other. The composition of the removable DOM by enhanced coagulation of the four coagulants was revealed and validated using 29 raw waters (in 13 source waters in three seasons), and as a result the low deviation indicated that the predicted data matched well with the actual data. It provided the possibility for the application in practical operation of water plant.
Publisher: Wiley
Date: 06-1999
Publisher: Inderscience Publishers
Date: 2016
Publisher: Elsevier BV
Date: 11-2016
DOI: 10.1016/J.WATRES.2016.08.052
Abstract: Prechlorination is commonly used to minimize operational problems associated with biological growth as well as taste and odor control during drinking water treatment. However, prechlorination can also oxidise micropollutants into intermediate byproducts. This could impose profound effects on the safety of the finished water if the transformed byproducts are more toxic and less removable. This study investigated the effect of prechlorination on decomposition and subsequent removal of the four organophosphorus pesticides (OPPs): chlorpyrifos, diazinon, malathion and tolclofos-methyl using a simulated conventional water treatment process of powdered activated carbon assisted coagulation-sedimentation-filtration (PAC-CSF) and postchlorination. It was found that, following prechlorination, not only did the percentage of OPPs oxidation vary significantly, but also the concentration of transformed oxons, which are more toxic than their parent compounds, increased as the major identified oxidation byproducts in water. Removal of these oxons proved to be more difficult by the PAC-CSF than their parent OPPs, because they are more water soluble and more hydrophilic. Both the OPP oxidation and oxon formation increased with chlorine dose during prechlorination. Meanwhile, the continuing chlorination of OPPs by residual free chlorine during PAC-CSF further complicated the pesticide removal processes, generally resulting in a gradually increased formation of oxons. Moreover, in the final treatment stage of postchlorination, the more chlorine-reactive pesticides, malathion and diazinon, were completely oxidised and the formation of corresponding oxons was increased with the prechlorine dose. In contrast, a certain amount of the less chlorine-reactive pesticide tolclofos-methyl still remained in solution after postchlorination, accompanied by an increased formation of tolclofos-methyl oxon with prechlorine dose. Since the oxons are resistant to further oxidation and less adsorbable during the PAC-CSF process, the gross removal of these pesticides and their oxons decreased with increase of the prechlorine dose. This led to an accumulation of the more toxic oxons in the finished water, especially at higher chlorine doses during prechlorination. The significance of this work is the demonstration that, under circumstances where prechlorination is used and source water contains traces of OPPs, alternative practices should be prioritized to avoid the potential risks involved in consumption of the treated water.
Publisher: Informa UK Limited
Date: 03-2013
Publisher: IWA Publishing
Date: 12-2009
DOI: 10.2166/WST.2009.753
Abstract: Permeable pavement reservoirs provide an important opportunity for the harvesting and storage of stormwater for reuse. This research aims to determine whether storage in dolomite, calcite and quartzite mineral aggregates in the base course of a permeable pavement impacts on the survival of the pathogen indicator organism Escherichia coli (E. coli) in storage. The reasons for depletion were also investigated. Twelve model permeable pavement storage reservoirs were filled, in triplicate, with dolomite, calcite and quartzite. Three reservoirs contained no aggregate. After filling with pathogen spiked rainwater, the concentration of E. coli was examined for 22 days in the reservoirs. The reservoirs were then agitated to determine if there was E. coli present which was not in aqueous suspension. The results of the experiments show that there is no significant difference in the depletion of E. coli found in reservoirs without aggregate, and those filled with dolomite or calcite. The rate of depletion was found to be significantly lower in the quartzite filled reservoirs. Agitation of the reservoirs yielded increases in the aqueous concentration of E. coli in all reservoir types, suggesting that the bacteria are adhering to the surface of the mineral aggregate and to the reservoir walls.
Publisher: IWA Publishing
Date: 1999
Publisher: Adelaide, SA, CSIRO Land & Water
Date: 2005
Publisher: Elsevier BV
Date: 05-2003
Publisher: Wiley
Date: 11-2005
DOI: 10.2134/JEQ2005.0013
Abstract: Concentrations of phosphorus (P) in runoff from agricultural catchments in southern Australia are high and well above national and international limits. Phosphorus was found to exit two subcatchments of 3.6 and 4.2 ha in the Adelaide hills via both overland flow and interflow. The subcatchments had texture-contrast soils with high inputs of superphosphate and were openly grazed by cattle all year. Interflow at the boundary of the B and C soil horizons accounted for as much as half the total water flow that was measured (overland flow, A-B interflow, and B-C interflow). The average flow-weighted concentration of total P within overland flow was as high as 0.25 mg L(-1), and 0.05 mg L(-1) in B-C interflow. In most years P loss was in the dissolved (<0.45 microm) form. In some years, interflow was the major pathway for P loss off these catchments. The B-C interflow cannot be discounted when searching for management options to reduce P loss from texture-contrast soils to waterways. Preliminary laboratory experiments showed promise that gypsum could modify agricultural soils and reduce the concentrations of P (and dissolved organic C) in runoff before it enters public water supply reservoirs. In this study, gypsum, applied at a rate of 15 Mg ha(-1) to the 4.2-ha subcatchment, substantially modified the soil chemistry, and thereby soil structure. The size and stability of structural aggregates increased markedly and this change affected not only the A but also the upper B horizons, to a profile depth of approximately 50 cm. However, the impact of these physicochemical changes on P concentrations in runoff was not marked. Average profile P concentrations were only slightly lower in the runoff from the subcatchment following treatment. The high subsoil macroporosity of the gypsum-treated subcatchment caused an increase in the proportion of runoff by interflow.
Publisher: American Chemical Society (ACS)
Date: 02-08-2008
DOI: 10.1021/ES800794R
Abstract: This paper reports the use of high performance size exclusion chromatography (HPSEC) as a tool to assess NOM removal by coagulation. Quantitative information such as percentage removal can be determined after "peak-fitting" the HPSEC molecular weight profile of the source water. A peak-fitting approach was developed based on the molecular weight profile of dissolved organic matter from surface water. A sequential jar testing procedure with five treatment steps was used to characterize organics and to confirm that several NOM components were recalcitrant to coagulation with alum. Despite differences found in both the concentration and character of NOM in three surface waters studied, the final concentrations and characteristics (e.g., molecular weight profile) were very similar after five treatment stages. The molecular weight profiles of the recalcitrant organics were subsequently used to build a peak-fitting technique for NOM removal. The approach was validated by further jar test results of several other water sources, such as ground and river waters, including one found to be very difficult to treat in terms of NOM removal by alum treatment. Predictions of removable and nonremovable organic fractions by coagulation using this peak fitting technique were found to be within 10% of actual values.
Publisher: Wiley
Date: 05-09-2001
DOI: 10.1002/JCTB.486
Publisher: Elsevier BV
Date: 12-2012
Publisher: Adelaide, SA, CSIRO
Date: 2006
Publisher: Elsevier BV
Date: 08-2015
Publisher: Elsevier BV
Date: 02-2010
Publisher: IWA Publishing
Date: 12-2012
DOI: 10.2166/WST.2012.448
Abstract: Resin fractionation is the most widely used technique to isolate and characterize natural organic matter (NOM) based on its hydrophobicity and hydrophilicity, however, it is also recognized as a time consuming technique. This paper describes the use of reverse phase high performance liquid chromatography (RPHPLC) as a rapid assessment technique to determine the hydrophobicity/hydrophilicity of NOM. The optimum column separation condition was achieved and without the need for concentrating the s le prior to analysis and with good reproducibility of the peak retention time and the peak area. The characterization results were further compared with the traditional resin fractionation technique using DAX-8 and XAD-4 resins. The results demonstrated that the polarities defined by the two methods were different but consistent and also that the fractions absorbed onto XAD-4 were less hydrophobic than those absorbed onto DAX-8. The difference in definition between resin fractionation and RPHPLC were further investigated.
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Funder: Australian Research Council
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Funder: Department of Environment, Water and Natural Resources
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Funder: Australian Research Council
View Funded ActivityStart Date: 2010
End Date: 2012
Funder: Australian Research Council
View Funded ActivityStart Date: 2011
End Date: 2013
Funder: Australian Research Council
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