Western Treatment Plant Research Articles

Identification of key water quality characteristics affecting the filterability of biologically treated effluent in low-pressure membrane filtration

There are many water quality characteristics which could influence the filterability of biologically treated effluent from Melbourne's Western Treatment Plant (WTP). Statistical correlation was used to identify the key water characteristics affecting the microfiltration (MF) and ultrafiltration (UF) filterability in terms of permeate volume of the treated effluent. The models developed showed that turbidity, dissolved organic carbon (DOC) and total suspended solids (TSS) were the key factors which influenced the MF and UF filterability. Turbidity was the dominant factor affecting the accuracy of the model for MF filterability while DOC was the major factor affecting the accuracy of the model for UF filterability. A prediction accuracy of 85% was obtained for MF and 86% for UF filterability of the WTP effluent. The characteristics of the organic components of the wastewater were demonstrated by EEM spectra to have seasonal variation which would have reduced the prediction accuracy. As turbidity, DOC and TSS can be determined on-line, the models would be useful for rapid prediction of the filterability of WTP effluent and this may assist the control of low-pressure membrane filtration processes.

Geotechnical laboratory testing of biosolids

Biosolids is the end product of the wastewater treatment process. An innovative research project on biosolids is currently being undertaken in Melbourne, Australia to characterize its geotechnical characteristic which is essential to evaluate the performance of biosolids in various geotechnical applications. The geotechnical engineering characteristics of biosolids at Western Treatment Plant (WTP) in Melbourne, Australia was investigated and presented in this paper. The tests undertaken include consolidation, triaxial shear strength, hydraulic conductivity, compaction, California Bearing Ratio, Atterberg limits, particle density and particle size distribution.

Case Study – Successful Operation of Biotechnology for Odour Control at Western Treatment Plant

Case Study – Successful Operation of Biotechnology for Odour Control at Western Treatment Plant

Assessment of the pollution potential of mercury contaminated biosolids

Environmental context. The re-use of biosolids (sewage sludge) is becoming increasingly popular especially for land applications as soil improvers, fertilisers and composts. However, some biosolids are contaminated with toxic heavy metals and mercury is arguably of the highest environmental and public health concern. Studies on mobility, availability and emissions of mercury from biosolids were carried out to assess the biosolids potential for contamination of the environment and to evaluate applicable techniques for a future remediation. Abstract. Biosolids from Melbourne Water’s Western Treatment Plant (WTP) in Australia contain elevated levels of mercury. Consequently, monitoring programs are crucial in order to assess localised impacts to the environment and on humans immediately surrounding the boundaries of the WTP. Dry biosolids were surveyed for Hg, other heavy metals, cations, soluble anions, sulfur and phosphorus. Mercury concentrations were found to vary between 3.5 and 8.4 mg kg–1 Hg, indicating that biosolids from some locations were above the safety level (5 mg kg–1 Hg) for land applications. High concentrations of soluble anions and cations revealed elevated salinity levels. The biosolids with the highest Hg concentration were further studied to assess their potential for Hg remediation. The results obtained by a sequential extraction procedure showed that 59.01% of the total mercury was complexed with organic ligands. In addition, the influence of air temperature, water content and irradiation on the emission of gaseous elemental mercury from biosolids was studied. Light exposure and water addition were the main factors affecting this emission with flux values up to 132 ng m–2 h–1.

Phytotoxicity of biosolids and screening of selected plant species with potential for mercury phytoextraction

Mercury contaminated stockpiles of biosolids (3.5-8.4 mg kg(-1) Hg) from Melbourne Water's Western Treatment Plant (MW-WTP) were investigated to evaluate the possibility for their phytoremediation. Nine plant species (Atriplex codonocarpa, Atriplex semibaccata, Austrodanthonia caespitosa, Brassica juncea, Brassica napus, Gypsophila paniculata, Sorghum bicolor, Themeda triandra and Trifolium subterraneum) were screened for phytoextraction potential in Hg-contaminated biosolids from MW-WTP. In addition, the same plant species were germinated and grown in two other substrates (i.e. potting mix and potting mix spiked with mercury(II)). Growth measurements and the mercury uptake for all three substrates were compared. Some plant species grown in potting mix spiked with mercury(II) grew more vigorously than in the other two substrates and showed higher levels of sulphur in their tissues. These results suggested that the mercury stress activated defence mechanisms and it was hypothesised that this was the likely reason for the enhanced production of sulphur compounds in the plant species studied which stimulated their growth. Some species did not grow in biosolids because of the combined effect of high mercury toxicity and high salt content. Atriplex conodocarpa and Australodanthonia caespitose proved to be the most suitable candidates for mercury phytoextraction because of their ability to translocate mercury from roots to the above-ground tissues.

A comparative study of microfiltration and ultrafiltration of activated sludge-lagoon effluent

Melbourne’s Western Treatment Plant is unusual in that it employs a sequential activated sludge-lagoon (AS-lagoon) system to treat municipal wastewater. Reuse of the treated water is limited for some applications due to salt content, and membrane pre-treatment prior to reverse osmosis is under consideration. The use of microfiltration (MF) and ultrafiltration (UF) for improving the quality of water prior to reverse osmosis was investigated. The organic components of the feed water (AS-lagoon effluent), permeates and foulant layers were characterised using three-dimensional excitation-emission-matrix (EEM) spectroscopy, attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR), dissolved organic carbon (DOC) determination, size exclusion chromatography (SEC) and ultraviolet (UV) absorbance. DOC removal was 28% for UF and 2% for MF. MF removed mostly non-UV absorbing molecules of AMW 40–70 kDa, whereas UF removed molecules in this size range, a high proportion of which were UV-absorbing, as well as some organic compounds in the 3–8 kDa range, some of which were UV-absorbing. The organic compounds removed by UF had hydrophobic, hydrophilic and transphilic character, and were shown to comprise humic-like matter, soluble microbial products and protein-like extracellular matter. Fulvic-like matter largely passed through the UF membrane. ATR-FTIR analysis of fouled MF and UF membranes showed that polysaccharides, polysaccharide-like compounds and proteins were the prominent components in the fouling layer.

Diagnostic analysis of RO desalting treated wastewater

Diagnostic analysis of reverse osmosis membranes that were fed with Western treatment plant (WTP) recycled water was investigated by both thermodynamic calculations and laboratory experiments in order to predict the feasibility of RO desalting for WTP. The thermodynamic calculations suggested that RO recoveries of 80–85% were feasible with careful control of feed water pH and the use of chemical additives such as antiscalants and chelating agents, it also predicted the major minerals of concern to be silica, calcium fluoride, calcium carbonate, and calcium phosphate. Following the thermodynamic simulations, diagnostic laboratory experiments were undertaken. The experiments showed that the major contributor to scale formation was indeed calcium phosphate and possibly another calcium based compound, which was strongly suspected to be calcium carbonate. Based on previously published literature that indicated anti-scalants did not substantially decrease the scaling effect of calcium phosphate and laboratory tests that indicated controlling the pH to 6.4 in the feed water dramatically reduced scaling formation, it was suggested that the feed water could be controlled by pH adjustments only. Inter-stage pH correction was suggested as an optional technique to enhance the overall water recovery to above 95%.

Excursion – Western Treatment Plant

Excursion – Western Treatment Plant

Case Study: Odour Risk Management at the Western Treatment Plant, one of Australia's Largest and Most Unique Wastewater Treatment Plants

Case Study: Odour Risk Management at the Western Treatment Plant, one of Australia's Largest and Most Unique Wastewater Treatment PlantsThe Western Treatment Plant (WTP) is one of Australia's largest and most unique wastewater treatment plants (WWTP) treating over 52% of Melbourne's sewage in a process consisting of open carriers, covered anaerobic lagoons, aerobic lagoons and activated sludge treatment. Large lagoons are also used for the storage and processing of dewatered waste activated sludge from a number of Barwon Water...Author(s)Josef CescaMethew CunningtonSourceProceedings of the Water Environment FederationSubjectSession 1: Methods of Sampling, Measuring, and Estimating Emissions IDocument typeConference PaperPublisherWater Environment FederationPrint publication date Jan, 2008ISSN1938-6478SICI1938-6478(20080101)2008:4L.1;1-DOI10.2175/193864708788807853Volume / Issue2008 / 4Content sourceOdors and Air Pollutants ConferenceFirst / last page(s)1 - 15Copyright2008Word count476

Potential microbial and chemical hazards to waterbirds at the Western Treatment Plant

Summary The Western Treatment Plant, a major sewage treatment plant west of Melbourne, Australia, is widely regarded as a significant conservation site for waterbirds. But experiences from various parts of the world suggest that sewage can also be hazardous to waterbirds, and has probably been responsible for mass‐kill events. The intent of this contribution is to raise awareness about the potential for adverse impacts of sewage treatment plants on waterbirds, and to stimulate debate on the issue, with the ultimate objective of developing appropriate management strategies to mitigate the risk of mass kills.

Excursion – Western Treatment Plant

Excursion – Western Treatment Plant

The ecology of sewage treatment gradients in relation to their use by waterbirds

The distribution and abundance of waterbirds along sewage treatment gradients at the Western Treatment Plant (Victoria, Australia) were studied in late summer/early autumn 2000. In general, the highest densities and diversity of waterbirds, and of zooplankton, were found in the ponds towards the end of a treatment series. Filter-feeding waterfowl (Anatidae) probably used these ponds because of the availability of zooplankton as a food-source. Dissolved oxygen concentration generally increased along the treatment gradient and un-ionised sulphide concentration decreased, and it is possible that either one, or both, of these played a key role in determining the distribution of zooplankton.

Multivariate monitoring of a biological wastewater treatment process: a case study at Melbourne Water's Western Treatment Plant

Biological wastewater treatment is a complex, multivariate process, in which a number of physical and biological processes occur simultaneously. In this study, principal component analysis (PCA) and parallel factor analysis (PARAFAC) were used to profile and characterise Lagoon 115E, a multistage biological lagoon treatment system at Melbourne Water's Western Treatment Plant (WTP) in Melbourne, Australia. In this study, the objective was to increase our understanding of the multivariate processes taking place in the lagoon. The data used in the study span a 7-year period during which samples were collected as often as weekly from the ponds of Lagoon 115E and subjected to analysis. The resulting database, involving 19 chemical and physical variables, was studied using the multivariate data analysis methods PCA and PARAFAC. With these methods, alterations in the state of the wastewater due to intrinsic and extrinsic factors could be discerned. The methods were effective in illustrating and visually representing the complex purification stages and cyclic changes occurring along the lagoon system. The two methods proved complementary, with each having its own beneficial features.

Lagoon Effluent Treatment Using Grass Filtration

The Western Treatment Plant (WTP) is one of the largest treatment plants in Australia treating more than 500 ML of sewage per day, discharging treated effluent to Port Phillip Bay in Victoria, Australia. The Port Phillip Bay Environmental Study (1992–1996) concluded that there was a need to reduce nitrogen loads from WTP to lower the risk of eutrophication, especially during winter when grass filtration was in operation. Therefore, in 1997, Melbourne Water initiated a pilot study to investigate the effectiveness of grass filtration for polishing wastewater that had received prior lagoon treatment. The study involved field monitoring of seven trial grass filtration bays at the WTP for hydraulic and water quality data from mid-May to early-October 1997. The results of the pilot study revealed that the removal rates of these nutrients were higher during the first half of the trials than during the second half. The results also showed that the removal rates of nutrients were inversely proportional to the hydraulic loading rates of the bays. A hydraulic loading rate of 40 mm/d was found to be optimal in this pilot study for achieving a balance between wastewater throughput and nutrient removal.

Variation in the response of intertidal infaunal invertebrates to nutrient additions: field manipulations at two sites within Port Phillip Bay, Australia

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 250:35-49 (2003) - doi:10.3354/meps250035 Variation in the response of intertidal infaunal invertebrates to nutrient additions: field manipulations at two sites within Port Phillip Bay, Australia Liz Morris1,2,*, Michael J. Keough2 1Department of Zoology, University of Melbourne, Melbourne 3010, Australia 2Present address: Marine and Freshwater Resources Institute, PO Box 114, Queenscliff 3225, Australia *Email: liz.morris@nre.vic.gov.au ABSTRACT: Nutrient addition experiments are one way of testing the importance of nutrients in ecological systems and can be undertaken relatively easily in soft sediments. We added nutrients (Osmocote®) at 2 sites in Port Phillip Bay, Australia, which differed in proximity to sources of nutrient loading. Changes in faunal assemblages were assessed over an 18 wk experimental period in 1998. At the Sand Island site, nitrate levels were elevated in the high dose treatments and 3 taxa showed responses to nutrient additions, with differences in densities between control and dosed plots of between 50 and 600%. Assemblage-level measures of total abundance and diversity were approximately 20 to 80% greater in dosed plots relative to controls at the end of the experimental period. In contrast, at the more enriched Western Treatment Plant site, 3 of the 10 most dominant taxa were affected by the nutrient additions, with changes of between 50 and 200% observed during the course of the experiment. At this site none of the assemblage level measures of abundance, biomass and diversity reflected an effect of the dose treatments. These results are broadly consistent with other studies that suggest that in areas of low ambient nutrient availability diversity is likely to increase, while in areas with high background nutrient loadings there is likely to be a decrease. At Sand Island, changing the nutrient status of the area is liable to result in rapid changes in several deposit-feeding populations. At the Western Treatment Plant, the same absolute change in N may have less impact on the invertebrate fauna. KEY WORDS: Western Treatment Plant · Swan Bay · Victoria · Benthos · Macroinvertebrates · Field experiments · Experimental power Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 250. Online publication date: March 26, 2003 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2003 Inter-Research.

Modelling treated waste disposal in Port Phillip Bay and Bass Strait: Biogeochemical and physical removal

Large cities, such as Melbourne, generate substantial quantities of sewage, which, after treatment, must be disposed. Melbourne's sewage is disposed via two routes, that treated at the Western Treatment Plant (WTP) is discharged in enclosed Port Phillip Bay, while the Boags Rock outfall empties into the exposed Bass Strait. In Port Phillip Bay biogeochemical processes control the fate of waste, while in the Bass Strait physical mixing rapidly disperses the waste. These different processes require very different ecosystem models. Port Phillip Bay requires detailed modelling of water-column and in-sediment processes, in particular detailed models of recycling processes, and also modelling of benthos–water-column interactions. Interaction of these components gives the model a nonlinear response to change in load. The Bass Strait ecosystem model is simple with no modelling of the sediment and limited modelling of water-column recycling. This model's behaviour is largely controlled by the physical environment.

The use of algal-bacterial biofilms to enhance nitrification rates in lagoons: experience under laboratory and pilot-scale conditions

Investigations were undertaken at the Western Treatment Plant (WTP), near Melbourne, Australia, to find ways of increasing overall ammonia and nitrogen removal rates in the WTP lagoon systems. Immobilisation of nitrifying bacteria in biofilms was one approach explored. Preliminary tests showed that algal/bacterial biofilms capable of achieving ammonia removal rates of 3 to 4 μg N/cm2·h would form on support surfaces immersed in the WTP lagoons. A laboratory-scale investigation was carried out to characterise the influence of parameters such as pH, temperature, COD level, dissolved oxygen concentration and incubation depth on biofilm performance. This study was followed by a pilot-scale investigation in a series of experimental ponds at the WTP. This compared the performance of three ponds, two containing 9360 m2 and 18240 m2 respectively of a geotextile biofilm support material and one containing no biofilm support material (the control pond). Ammonia removal rates comparable to those obtained in the preliminary tests were obtained when the biofilm support material was within the top 500 mm of the lagoon, i.e. in the photic zone. COD and suspended solids levels in the effluents from the biofilm containing ponds were substantially lower than those in the control pond effluent.

A contour plot approach that uses data accumulated during routine monitoring to obtain insights into lagoon behaviour

Regular monitoring of wastewater characteristics is undertaken on most wastewater treatment plants. The data acquired during this process are usually filed and forgotten. However, systematic analysis of these data can provide useful insights into plant behaviour. Conventional graphical techniques are inadequate to give a good overall picture of how wastewater characteristics vary, with time and along the lagoon system. An approach based on the use of contour plots was devised that largely overcomes this problem. Superimposition of contour plots for different parameters can be used to gain a qualitative understanding of the nature and strength of relationships between the parameters. This is illustrated in an analysis of monitoring data for lagoon 115 East at the Western Treatment Plant, near Melbourne, Australia. In this illustrative analysis, relationships between ammonia removal rates and parameters such as chlorophyll a level and temperature are explored using a contour plot superimposition approach. It is concluded that this approach can help improve our understanding, not only of lagoon systems, but of other wastewater treatment systems as well.

Floating geomembrane covers for odour control and biogas collection and utilization in municipal lagoons

The use of anaerobic lagoons as the first pond in waste stabilization pond systems in tropical and warm-temperature climates is considered a highly cost-effective and practical way to treat municipal wastewater. These anaerobic ponds, designed with hydraulic residence times of up to six days, can effect BOD5 removals of 60 to 80%. The subsequent aerobic stabilization pond surface area is greatly reduced over systems designed without anaerobic treatment up front due to the organic load reduction occurring anaerobically. In lagoon systems with mechanical aeration, operation costs can be greatly reduced. While odour is a concern with anaerobic treatment, anaerobic ponds treating municipal wastewater can be designed to be relatively odour-free given sufficiently low wastewater sulfate concentrations. However, when sulfate concentrations are high, or when odour control or greenhouse gas emissions are significant issues, or when the wastewater is relatively high in organic strength resulting in commercial production of methane gas, anaerobic lagoons can be covered, and the biogas collected and burned both to produce energy and reduce emissions and odour. The City of Melbourne treats approximately 50% of its municipal wastewater at the Western Treatment Plant in waste stabilization ponds designed with anaerobic ponds as the first pond in the system. Each of three pond systems at the Western Treatment Plant receives an average dry weather flow of 120,000 m3/d with an average strength of 400 mg/L BOD5. This paper describes the design, installation and commissioning of two 3.9 hectare floating, self draining, geomembrane covers on the anaerobic section of two of these lagoon systems. Biogas collection and utilization were an important part of the installation. A description of how the biogas is collected, the quantities generated and an overview of the control system used to operate the biogas handling facility is also included. Particular emphasis was placed on maximizing biogas utilization in design of the biogas control system.

A contour plot technique for depicting wastewater lagoon parameters and analysing their interrelatedness

Most wastewater treatment plants regularly monitor plant performance. Analysis of the resulting data can provide valuable insights into plant behaviour. A useful first step in the systematic analysis of such data is to depict them graphically. The resulting plots help identify the more obvious relationships between measured wastewater characteristics. They also help in locating anomalous data points. In the case of multi-pond wastewater treatment lagoons, finding an informative way of depicting the monitoring data is difficult. This is because the required data plots need to show not only how measured characteristics vary with time but also how they vary along the pond chain. Conventional 2-D “time-series” plots are inadequate for this task if the lagoon comprises more than a few ponds, or if the amount of accumulated data is large. An alternative, contour plot based approach was developed that overcomes the problems with conventional 2-D plots. The procedure for producing such plots is described and factors affecting their accuracy discussed. A major advantage of the contour plot approach is that contour plots for different parameters can be superimposed. By examining these superimposed plots, one can learn much about the way different parameters are related. A procedure is described that enables the interrelatedness of any given pair of parameters to be systematically characterised. The effectiveness of the contour plot approach is illustrated using data obtained over a 9-year period for an 11 (later 10) pond lagoon at the Western Treatment Plant in Melbourne, Australia.