This project has four specific objectives: (1) To identify ways to prevent or reduce the incidence of foaming during anaerobic digestion of sewage sludge; (2) to identify the core microbiome associated with efficient digestor performance during stabilisation of sewage sludge; (3) to assess how changes in the reactor environment affect contaminant transformations; (4) to assess the impacts of biosolid post-treatments on the metabolic capacity of the microbial community, pathogen-survival, contaminant-transformations and ecotoxicology of final products.

PhD Thesis underway by Timothy Micallef.

This project characterised the acute cytotoxicity of a hydraulic fracturing fluid using a human gastrointestinal cell line and, using this data, contribute to the understanding of potential human health risks posed by Coal Seam Gas (CSG) extraction in Queensland.

Honours Thesis completed by Madeleine Payne in October 2012.

Anabaena circinalis, is a commonly occurring cyanobacterial species in Australian source waters. Its presence poses a number of health and aesthetic issues for drinking water quality due to its production of secondary metabolites. This project isolated and characterised a novel toxic fraction from the Anabaena culture.

Honours Thesis completed by Stefania Sotora in November 2012.

This project proposes to use novel concepts in computational chemistry to predict the likely transformation products (TP) of relevant EDCs/PPCPs with a range of disinfection and oxidation options (such as chlorine, chloramines and chlorine dioxide) commonly used in the production of drinking water, and to apply comprehensive in vitro toxicity testing to determine their likely toxicity profile.

Wastewater must be treated to remove harmful pathogens and chemicals before it can be released to the environment, but the cost of proving that all pollutants have been removed is prohibitive because potentially thousands of separate chemicals would have to be measured. Another problem is that classical chemistry measurement tests are sometimes not sensitive enough to be able to detect the very low levels of chemicals which still harm animals and plants. This research developed a suite of extremely sensitive in vitro cell culture tests and an in-situ laboratory test in which mosquitofish were observed when swimming in recycled treated water. These bioassays measured the effects of mixtures of contaminants and were compared with traditional chemical measurements of separate contaminants. The in vitro cell culture, in situ mosquitofish and classical chemical analyses of selected contaminants generated equivalent results and led to the conclusion that combining multiple lines of evidence into a toolbox approach for the assessment of water quality provides data which is more informative and relevant when assessing potential impacts on the environment than traditional chemical measurements alone.

Wastewater (WW) contains harmful chemicals, including pesticides, that can disrupt normal gene function or hormone activity. The cost of measuring each separate contaminant at the frequency needed to demonstrate the safety of recycled WW is prohibitive. This research reviewed the risk assessment and regulation of chemicals in Australian water, with a focus on ‘thresholds of toxicological concern’. Laboratory techniques were developed to extract and concentrate WW contaminants into solutions suitable for analysis using both new in vitro cell culture assays and analysis in expensive, established chemical tests. WW and treated samples were collected from nine Australian water reclamation plants. The total effect of each sample (which contained a mixture of contaminants) on cell death, gene integrity and aspects of liver, hormone, nerve and immune system activity, was determined using in vitro cell culture bioassays, and compared with the classical chemical measurement of each separate contaminant. The cheaper cell-culture tests correlated well to the levels of groups of chemicals and could be used to find thresholds of toxicological concern. Both testing regimens also demonstrated that reverse osmosis is a highly effective method that removes harmful chemicals to levels much lower than those designated safe by regulatory authorities.

Disinfection is essential for removing harmful microbial pathogens and making safe drinking water but can also cause formation of disinfection by-products (DBPs), some of which pose a health risk. Thirty years of research have amassed a wealth of knowledge about the identification, formation, treatment and control, toxicology and epidemiology of DBPs in Australia. This project compiled, assessed and presented an overview of DBP-related research in Australia.