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Hardisty P.E.,Level 7 Systems | Hardisty P.E.,University of Western Australia | Sivapalan M.,WorleyParsons EcoNomics | Humphries R.,Water Corporation of Western Australia
Journal of Environmental Management | Year: 2013

Options for treatment and discharge of wastewater in regional Western Australia (WA) are examined from the perspective of overall sustainability and social net benefit. Current practice in the state has typically involved a basic standard of treatment deemed to be protective of human health, followed by discharge to surface water bodies. Community and regulatory pressure to move to higher standards of treatment is based on the presumption that a higher standard of treatment is more protective of the environment and society, and thus is more sustainable. This analysis tests that hypothesis for Western Australian conditions. The merits of various wastewater treatment and discharge strategies are examined by quantifying financial costs (capital and operations), and by monetising the wider environmental and social costs and benefits of each option over an expanded planning horizon (30 years). Six technical treatment-disposal options were assessed at a test site, all of which met the fundamental criterion of protecting human health. From a financial perspective, the current business-as-usual option is preferred - it is the least cost solution. However, valuing externalities such as water, greenhouse gases, ecological impacts and community amenity, the status quo is revealed as sub-optimal. Advanced secondary treatment with stream disposal improves water quality and provides overall net benefit to society. All of the other options were net present value (NPV) negative. Sensitivity analysis shows that the favoured option outperforms all of the others under a wide range of financial and externality values and assumptions. Expanding the findings across the state reveals that moving from the identified socially optimal level of treatment to higher (tertiary) levels of treatment would result in a net loss to society equivalent to several hundred million dollars. In other words, everyone benefits from improving treatment to the optimum point. But society, the environment, and the Corporation are all worse off when treatment levels are pushed beyond what is economic and sustainable. © 2012 Elsevier Ltd. Source

Pearce L.J.,Water Corporation of Western Australia
Proceedings of the 34th Hydrology and Water Resources Symposium, HWRS 2012 | Year: 2012

Usual flood estimation practice in Australia is to produce annual design floods based on assessment of annual flood peaks. Combining summer and winter flood frequency results to construct an overarching annual frequency curve can produce different results to the commonly adopted annual method. In south-west Western Australia flood events are strongly influenced by seasonality. This is a consequence of differing storm mechanisms and antecedent conditions of summer and winter events. Seasonal rainfall frequency distributions indicate most summer rainfalls dominate the low probability exceedance end of frequency curves. Equivalent flood frequency analysis shows similar tendencies, but with summer dictating at rarer probabilities than rainfall. The exceedance probability at which summer dominates is influenced by region, soil types, percentage clearing and impervious areas. This paper addresses the importance of seasonality in design flood estimation. © 2012 Engineers Australia. Source

Bekele E.,CSIRO | Toze S.,CSIRO | Toze S.,University of Queensland | Patterson B.,CSIRO | And 2 more authors.
Water Research | Year: 2011

Secondary treated wastewater was infiltrated through a 9 m-thick calcareous vadose zone during a 39 month managed aquifer recharge (MAR) field trial to determine potential improvements in the recycled water quality. The water quality improvements of the recycled water were based on changes in the chemistry and microbiology of (i) the recycled water prior to infiltration relative to (ii) groundwater immediately down-gradient from the infiltration gallery. Changes in the average concentrations of several constituents in the recycled water were identified with reductions of 30% for phosphorous, 66% for fluoride, 62% for iron and 51% for total organic carbon when the secondary treated wastewater was infiltrated at an applied rate of 17.5 L per minute with a residence time of approximately four days in the vadose zone and less than two days in the aquifer. Reductions were also noted for oxazepam and temazepam among the pharmaceuticals tested and for a range of microbial pathogens, but reductions were harder to quantify as their magnitudes varied over time. Total nitrogen and carbamazepine persisted in groundwater down-gradient from the infiltration galleries. Infiltration does potentially offer a range of water quality improvements over direct injection to the water table without passage through the unsaturated zone; however, additional treatment options for the non-potable water may still need to be considered, depending on the receiving environment or the end use of the recovered water. © 2011. Source

Marti C.L.,University of Western Australia | Antenucci J.P.,University of Western Australia | Luketina D.,Water Corporation of Western Australia | Okely P.,University of Western Australia | Imberger J.,University of Western Australia
Journal of Hydraulic Engineering | Year: 2010

Field experiments were conducted to investigate the near-field dilution characteristics of a hypersaline brine discharge into coastal waters via an offshore diffuser from a desalination plant. The aim was to determine the dilution of the negatively buoyant plume as it exited the diffuser under three different discharge Froude number regimes (one-third, two-thirds, and full-flow capacity) and to compare these measurements to scaling arguments derived from laboratory measurements. Equations based on the densimetric jet Froude number F, obtained from laboratory experiments, were found to adequately describe the dilution of the brine for cases when F>20. For F<20, no laboratory results exist and the dilution was found to be greater than that anticipated from an extrapolation of the laboratory results. © 2011 ASCE. Source

Cardell-Oliver R.,Cooperative Research Center for Water Sensitive Cities | Cardell-Oliver R.,University of Western Australia | Wang J.,Cooperative Research Center for Water Sensitive Cities | Wang J.,University of Western Australia | Gigney H.,Water Corporation of Western Australia
Journal of Water Resources Planning and Management | Year: 2016

Knowledge of when, how, and by whom water is being used is crucial for planning ways to conserve drinking water. The goal of this paper is to identify groups of similar households (whom) based on their regular high-magnitude behaviors (RHMBs) of water consumption (when and how). RHMBs are frequent recurrences of high water use with regular timing. Household RHMBs are promising targets for behavior change. A two-stage data analytics approach is proposed. First, smart meter data is analyzed to identify RHMBs automatically. Second, salient features of the RHMBs are used to group households with similar behaviors. The approach is evaluated on two contrasting towns from low-rainfall regions of Australia. RHMBs accounted for 2 to 10 times more water than the traditional water efficiency target of continuous flows. For one group of 220 households, 60% of peak-hour demand was RHMBs. This paper demonstrates how RHMBs can be used to pinpoint opportunities for tailored demand management. Targets for substantial reductions in water consumption and supply costs are identified. © 2016 American Society of Civil Engineers. Source

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