Leederville, Australia
Leederville, Australia

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Leusch F.D.L.,Griffith University | Khan S.J.,University of New South Wales | Gagnon M.M.,Curtin University Australia | Quayle P.,Griffith University | And 7 more authors.
Water Research | Year: 2014

We investigated water quality at an advanced water reclamation plant and three conventional wastewater treatment plants using an "ecotoxicity toolbox" consisting of three complementary analyses (chemical analysis, invitro bioanalysis and in situ biological monitoring), with a focus on endocrine disruption. The invitro bioassays were chosen to provide an appropriately wide coverage of biological effects relevant to managed aquifer recharge and environmental discharge of treated wastewater, and included bioassays for bacterial toxicity (Microtox), genotoxicity (umuC), photosynthesis inhibition (Max-I-PAM) and endocrine effects (E-SCREEN and AR-CALUX). Chemical analysis of hormones and pesticides using LCMSMS was performed in parallel to correlate standard analytical methods with the invitro assessment. For two plants with surface water discharge into open drains, further field work was carried out to examine in situ effects using mosquitofish (Gambusia holbrooki) as a bioindicator species for possible endocrine effects. The results show considerable cytotoxicity, phytotoxicity, estrogenicity and androgenicity in raw sewage, all of which were significantly reduced by conventional wastewater treatment. No biological response was detected to RO water, suggesting that reverse osmosis is a significant barrier to biologically active compounds. Chemical analysis and in situ monitoring revealed trends consistent with the invitro results: chemical analysis confirmed the removal trends observed by the bioanalytical tools, and in situ sampling did not reveal any evidence of endocrine disruption specifically due to discharge of treated wastewater (although other sources may be present). Biomarkers of exposure (invitro) and effect (invivo or in situ) are complementary and together provide information with a high level of ecological relevance. This study illustrates the utility of combining multiple lines of evidence in the assessment of water quality. © 2013 Elsevier Ltd.

Linge K.L.,Curtin University Australia | Blythe J.W.,Kellogg Brown and Root | Busetti F.,Curtin University Australia | Blair P.,Water Corporation | And 2 more authors.
Separation and Purification Technology | Year: 2013

A suite of 34 disinfection by-products (DBPs), including eight halomethanes, nine haloacetic acids, six haloacetonitriles, six haloaldehydes, four haloketones and the halonitromethane chloropicrin, were monitored in two microfiltration (MF) and reverse osmosis (RO) treatment plants as part of a larger study of chemical removal by MF/RO treatment for water recycling purposes. Both DBP detection frequency and concentration increased during treatment, and this was attributed to a chloramination step used to minimize RO membrane fouling. The degree of DBP formation was particularly related to plant residence time, with DBPs falling into two distinct groups; the first group in which DBP concentration increased with increasing residence time (e.g. chloroform and bromochloroacetaldehyde) and a second group in which increased residence time did not affect the concentration (e.g. dichloroacetic acid and 1,1-dichloropropanone). These results indicate that MF/RO plant design and wastewater quality are both important factors in minimizing DBP formation within MF/RO treatment. RO rejection was influenced by several chemical-specific properties, including pKa, log Kow and DBP class. Rejection of haloacetic acids, present as charged molecules, was consistently better than 90% and did not alter with log Kow. For all other DBPs, present as neutral molecules, rejection was much more variable, and decreased with decreasing log Kow, although the effect of MW and log Kow on rejection could not be separated. The DBP formation described in this study lead to variable estimations of DBP removal by RO and thus it is recommended that DBPs are used as indicators of RO removal efficiency with caution, and only after DBP formation within RO treatment has been studied. © 2012 Elsevier B.V. All rights reserved.

PubMed | South Australian Water Corporation, University of Western Australia, Water Corporation and Murdoch University
Type: Journal Article | Journal: PloS one | Year: 2017

Next generation sequencing (NGS) has rapidly become an invaluable tool for the detection, identification and relative quantification of environmental microorganisms. Here, we demonstrate two new 16S rDNA primer sets, which are compatible with NGS approaches and are primarily for use in water quality studies. Compared to 16S rRNA gene based universal primers, in silico and experimental analyses demonstrated that the new primers showed increased specificity for the Cyanobacteria and Proteobacteria phyla, allowing increased sensitivity for the detection, identification and relative quantification of toxic bloom-forming microalgae, microbial water quality bioindicators and common pathogens. Significantly, Cyanobacterial and Proteobacterial sequences accounted for ca. 95% of all sequences obtained within NGS runs (when compared to ca. 50% with standard universal NGS primers), providing higher sensitivity and greater phylogenetic resolution of key water quality microbial groups. The increased selectivity of the new primers allow the parallel sequencing of more samples through reduced sequence retrieval levels required to detect target groups, potentially reducing NGS costs by 50% but still guaranteeing optimal coverage and species discrimination.

Lee E.,Murdoch University | Ryan U.M.,Murdoch University | Monis P.,South Australian Water Corporation | McGregor G.B.,Information Technology | And 3 more authors.
Water Research | Year: 2014

Reliable identification of cyanobacterial isolates has significant socio-economic implications as many bloom-forming species affect the aesthetics and safety of drinking water, through the production of taste and odour compounds or toxic metabolites. The limitations of morphological identification have promoted the application of molecular tools, and encouraged the adoption of combined (polyphasic) approaches that include both microscopy- and DNA-based analyses. In this context, the rapid expansion of available sequence data is expected to allow increasingly reliable identification of cyanobacteria, and ultimately resolve current discrepancies between the two approaches.In the present study morphological and molecular characterisations of cyanobacterial isolates (n=39), collected from various freshwater sites in Australia, were compared. Sequences were obtained for the small ribosomal subunit RNA gene (16S rDNA) (n=36), the DNA-dependent RNA polymerase gene (rpoC1) (n=22), and the phycocyanin operon, with its intergenic spacer region (cpcBA-IGS) (n=19). Phylogenetic analyses identified three cyanobacterial orders: the Chroococcales (n=8), Oscillatoriales (n=6), and Nostocales (n=25). Interestingly, multiple novel genotypes were identified, with 22% of the strains (17/77) having <95% similarity to available sequences in GenBank.Morphological and molecular data were in agreement at the species level for only 26% of the isolates obtained (10/39), while agreement at the genus level was obtained for 31% (12/39). Confident identification of the remaining 44% of the strains (17/39) beyond the order level was not possible. The present study demonstrates that, despite the taxonomic revisions, and advances in molecular-, and bioinformatics-tools, the lack of reliable morphological features, culture-induced pleomorphism, and proportion of misidentified or poorly described sequences in GenBank, still represent significant factors, impeding the confident identification of cyanobacteria species. © 2014 Elsevier Ltd.

Kinkela K.,Water Corporation | Pearce L.J.,Water Corporation
Australian Journal of Water Resources | Year: 2014

Design flood events are strongly influenced by seasonality in southwest Western Australia (WA). This region is also known to be dominated by potentially high baseflow contributions during large floods. The proportion of baseflow to use in design has limited understanding, especially in the large to extreme flood range. Australian Rainfall and Runoff Update Project 7 used an adapted version of the Lyne & Hollick (1979) baseflow separation method to develop prediction equations that estimate baseflow contributions for annual design floods. This study found that the Lyne & Hollick separation technique was not applicable to all sites in southwest WA. Instead a manual graphical separation technique was adopted which provided more representative baseflow separations. Catchment specific and regional seasonal trends were derived and upper envelope curves were adopted for regional design estimates to ensure baseflow contribution was not underestimated. In the Darling Scarp region the recommended baseflow proportion to the total flood peak for rare to extreme design floods is 4% in summer and 11% in winter. The highly variable nature of baseflow response suggests that, where possible, at-site gauged data should be analysed to assess design baseflow contribution. © Institution of Engineers Australia, 2014.

Krstevski S.,Water Corporation
Urban Water Management: Challenges and Oppurtunities - 11th International Conference on Computing and Control for the Water Industry, CCWI 2011 | Year: 2011

This paper explores secondary transients experienced in a large transfer system as a result of an imposed power failure at the pump station. The focus is on high pressure fluctuations on the suction pipe of the pump station, between the surge vessel and the pumping units. The model results indicating a rapid pressure drop on the upstream side of the non return valve were confirmed by the field test using high speed pressure loggers, although the tests show a lesser extent of fluctuations. The paper discusses the uncertainty and lack of prospect for adequate calibration of the model because of the simultaneous impact of multiple parameters not included in the original model such as transient friction factor, air dissolved in the water at different pressure, transient air cavities, elasticity of vessels, fluid-structure interaction and water leaks. The results from a recent study indicate that while the models are valuable tool during planning-design stage, they are inferior compared to field tests while assessing performance or fine tuning operational settings of the real system.

Ni B.-J.,University of Queensland | Ye L.,University of Queensland | Law Y.,University of Queensland | Byers C.,Water Corporation | Yuan Z.,University of Queensland
Environmental Science and Technology | Year: 2013

Mathematical modeling of N2O emissions is of great importance toward understanding the whole environmental impact of wastewater treatment systems. However, information on modeling of N2O emissions from full-scale wastewater treatment plants (WWTP) is still sparse. In this work, a mathematical model based on currently known or hypothesized metabolic pathways for N2O productions by heterotrophic denitrifiers and ammonia-oxidizing bacteria (AOB) is developed and calibrated to describe the N2O emissions from full-scale WWTPs. The model described well the dynamic ammonium, nitrite, nitrate, dissolved oxygen (DO) and N2O data collected from both an open oxidation ditch (OD) system with surface aerators and a sequencing batch reactor (SBR) system with bubbling aeration. The obtained kinetic parameters for N2O production are found to be reasonable as the 95% confidence regions of the estimates are all small with mean values approximately at the center. The model is further validated with independent data sets collected from the same two WWTPs. This is the first time that mathematical modeling of N2O emissions is conducted successfully for full-scale WWTPs. While clearly showing that the NH2OH related pathways could well explain N2O production and emission in the two full-scale plants studied, the modeling results do not prove the dominance of the NH2OH pathways in these plants, nor rule out the possibility of AOB denitrification being a potentially dominating pathway in other WWTPs that are designed or operated differently. © 2013 American Chemical Society.

Ye L.,University of Queensland | Ni B.-J.,University of Queensland | Law Y.,University of Queensland | Law Y.,Nanyang Technological University | And 2 more authors.
Water Research | Year: 2014

The quantification of nitrous oxide (N2O) emissions from open-surface wastewater treatment systems with surface aerators is difficult as emissions from the surface aerator zone cannot be easily captured by floating hoods. In this study, we propose and demonstrate a novel methodology to estimate N2O emissions from such systems through determination of the N2O transfer coefficient (kLa) induced by surface aerators based on oxygen balance for the entire system. The methodology is demonstrated through its application to a full-scale open oxidation ditch wastewater treatment plant with surface aerators. The estimated kLa profile based on a month-long measurement campaign for oxygen balance, intensive monitoring of dissolved N2O profiles along the oxidation ditch over a period of four days, together with mathematical modelling, enabled to determine the N2O emission factor from this treatment plant (0.52±0.16%). Majority of the N2O emission was found to occur in the surface aerator zone, which would be missed if the gas hood method was applied alone. © 2013 Elsevier Ltd.

Rygaard M.,Technical University of Denmark | Arvin E.,Technical University of Denmark | Bath A.,Water Corporation | Binning P.J.,Technical University of Denmark
Water Research | Year: 2011

It is possible to optimize drinking water composition based on a valuation of the impacts of changed water quality. This paper introduces a method for assessing the potential for designing an optimum drinking water composition by the use of membrane desalination and remineralization. The method includes modeling of possible water quality blends and an evaluation of corrosion indices. Based on concentration-response relationships a range of impacts on public health, material lifetimes and consumption of soap have been valued for Perth, Western Australia and Copenhagen, Denmark. In addition to water quality aspects, costs of water production, fresh water abstraction and CO 2-emissions are integrated into a holistic economic assessment of the optimum share of desalinated water in water supplies. Results show that carefully designed desalination post-treatment can have net benefits up to €0.3 ± 0.2 per delivered m 3 for Perth and €0.4(±0.2) for Copenhagen. Costs of remineralization and green house gas emission mitigation are minor when compared to the potential benefits of an optimum water composition. Finally, a set of optimum water quality criteria is proposed for the guidance of water supply planning and management. © 2011 Elsevier Ltd.

PubMed | Water Corporation and Curtin University Australia
Type: | Journal: Environmental management | Year: 2017

This research has determined the carbon footprint or the carbon dioxide equivalent (CO

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