39 SEPTEMBER 2010 water Abstract The Western Australia’s Premier’s Collaborative Research Program (PCRP) project ‘Characterising Treated Wastewater for Drinking Purposes Following Reverse Osmosis Treatment’ commenced in October 2005, to determine the potential risks of replenishing drinking water aquifers with MF/RO treated secondary wastewater from Perth’s wastewater treatment plants. A brief report on the project won the Michael Flynn Award for the best poster paper at Ozwater’10. The results included those published in Water, February 2010, by Rodriguez et al, entitled Efficiency of RO for Removal of Chemical Contaminants. Consequently, this version has been drafted to cover the other aspects of the study, principally the identification of suitable indicators which could be used to validate treatment performance. Introduction In recent years Perth has experienced a significant reduction in water available from dams and groundwater. Population growth, decreases in traditional drinking water sources and climate variability mean that Perth needs to look increasingly at using water more efficiently and developing new water sources. One of several government strategies is through recycling of treated wastewater. However, a lack of knowledge of health and environmental risks associated with chemicals in wastewater has been a barrier preventing establishment of large reuse schemes. In 2005 the Western Australian government awarded a grant to the Department of Health, Department of Environment, Water Corporation of Western Australia, Curtin University, ChemCentre, CSIRO and the National Measurement Institute to complete a collaborative project on recycled water quality in the context of potential re- injection to groundwater. The specific objectives of the project were: • To analyse the final treated wastewaters from the Water Corporation’s three large metropolitan wastewater treatment plants (WTTPs) to characterise their microbial and chemical constituents and understand any seasonal and catchment differences in trace contaminants of concern in relation to human health and health of the environment; • To assess the performance of microfiltration and reverse osmosis (MF/RO) membrane treatment at the Kwinana Water Reclamation Plant (KWRP) and the specially constructed Beenyup Pilot Plant (BPP), to consistently produce water meeting the various health and environmental guidelines for augmentation of drinking water supplies by re-injection into groundwater; • To use the research output to develop and refine health and environmental guidelines for aquifer recharge of recycled water for indirect potable reuse on the Swan Coastal Plain. Chemical and Data Analysis Almost 400 chemicals, in 15 different chemical classes (see Table 1), were tested in the project. Eight laboratories were involved in the analysis and more than 20,000 records produced, not including field and trip blanks. Chemicals were selected for analysis based on their current use in Western Australia, their toxicological concern and evidence of detection in wastewater reported in the literature. Measured contaminant concentrations were compared with established drinking water standards and requirements or other toxicological guidelines to determine human health risks (Rodriguez et al., 2007). As guidelines and standards had not been developed for many chemicals, the threshold of toxicological concern was used for the preliminary health risk assessment to determine key contaminants that need to be monitored (Rodriguez et al., 2007). The data collected was used to calculate the percentage detection and median concentrations in wastewater and MF/RO treated water (post-RO water) for each chemical. Analysis by wastewater treatment plant (WWTP) and by season was also conducted. Treatment efficiency was calculated for chemicals detected in wastewater using wastewater and post- Figure 1. A schematic showing MF/RO treatment process and the sampling locations for wastewater, post-MF and post-RO samples. A pre-chloramination step used to protect the RO membrane is also highlighted and was found to increase concentration of some chemicals, such as disinfection by-products, during MF/RO treatment. wastewater treatment refereed paper technical features VALIDATION OF DUAL MEMBRANE TREATMENT FOR INDIRECT POTABLE REUSE K Linge, P Blair, F Busetti, C Rodriguez, M Handyside, J Blythe, M Bromley, O Lord, S Higginson, A Heitz, C Joll, C Newby, S Toze Evidenced-based approach to recycled water safety for groundwater replenishment. brought to you by CORE View metadata, citation and similar papers at core.ac.uk provided by espace@Curtin