In Australia, around 1.4 million tonnes of biosolids were produced in 2021. Land application of biosolids can promote environmental benefits such as: improve soil structure, carbon sequestration, cycling of nutrients as well as realising economic benefits through conserved landfill space, increased crop production and reduced demand for fertilizers. However, biosolids can have negative impacts on the environment if not properly managed.  Currently there is a lack of data on volatile emissions from biosolids when applied to land in Australia. Volatile emissions as well as impacting the environment can contribute to odours which reduce the community acceptance. Variations in volatile emissions can occur due to wastewater origins, biosolids processing, application methods and local conditions. This project aims to 1) identify and collate data from literature and industry on biosolids land application practices in Australia, and 2) measure volatile emissions from different biosolids, biosolids-amended soils and land application methods to inform best practice.

PhD Thesis underway by Thais Nunes Guerrero.

Unexpected taste and odour (T&O) in drinking water is an emerging issue for the Australian water industry as it undermines customers’ trust in drinking water suppliers. Most water utilities monitor only cyanobacterial and microalgal populations, and measure only geosmin and MIB concentrations in raw water, which is likely to overlook the full extent of biogenic T&O challenges in the supply of drinking water. Conventional coagulation/flocculation/filtration are often adopted for T&O removal. The project intends to identify key producers in source water and determine the treatability of unknown T&O for the proactive management of drinking water.

PhD Thesis underway by Jin Zhu.

The Australian water industry is currently focused on two VOCs, namely geosmin and MIB, which release an earthy-musty smell. Microorganisms that live in source water or within water distribution pipes are known to produce other unpleasant VOCs. This project intends to detect and quantify taste and odour (T&O) chemicals beyond geosmin and MIB in source water through chemical and sensory analysis. Project aims to identify and/or semi-quantify these unknown VOCs in source water and develop T&O wheel specific to NSW source water. The project also anticipates developing a risk indicator database for different T&O chemicals.

Thesis underway.

Source water protection underpins the safety and affordability of drinking water supplies where the prevention of water contamination provides greater surety than removal of contaminants. The Australian Drinking Water Guidelines emphasises the protection of source waters to the maximum degree possible as part of the multiple barrier approach to mitigate possible contamination.

Meanwhile, water utilities have been placed under increasing pressure to introduce or increase recreational access to drinking water catchments and water storages. There is also a lack of consensus around the impacts of different types of recreational access across Australia.

This project will summarise the current state of play of recreational access in Australia, report on the risks associated with different types of access, outline the types of cost benefit analyses that utilities can use when assessing recreational access, and promote a national understanding of risk to public health and water security.

The environmental conditions which cause blue-green algae (cyanobacteria) blooms vary according to location, the climate, and other attributes of aquatic ecosystems. This variety has made it difficult to develop one broadly applicable predictive model for cyanobacterial blooms. Water utilities monitor source waters to implement cyanobacterial risk management programmes but there are no standard protocols while limited information transfer between utilities has prevented the identification of management strategies that do or do not work. This research reviewed literature about early warning systems (Almuhtaram et al., 2021) and source control strategies, conducted a survey of 35 utilities in America and Canada (74%) and Australia (Kibuye et al., 2021) and evaluated selected control strategies. These different types of information were synthesised into decision trees within an overarching guidance document. It was concluded that a 3-tier framework to detect algal blooms which monitored biological activity, then confirmed the identification of cyanobacterial genes and associated metabolites gave sufficient early warning, while multi-barrier control strategies gave field-scale efficacy and enabled timely responses.

Recycled stormwater has a range of possible uses that have different levels and types of human exposure. Before systems to collect and re-use stormwater are established it is important to identify and measure the risk stormwater poses to human health and the environment. This research collected samples from two sites after 12 rainfall events. Low levels of herbicides and other chemicals were found in all samples, lower than the threshold considered safe by the Australian Guidelines for Drinking Water (ADWG), but higher than levels Environment Protection Agencies permit for injection into natural acquifers. These low levels probably caused some of the toxic effects observed in the in vitro cell culture tests. There were very low levels of pathogens that can infect humans in some samples. It was concluded that stormwater should be treated before being re-used for a range of applications which might include replenishing acquifers and that it would be sensible to survey stormwater catchments and in some cases treat stormwater from specific contaminated sites because this would be more cost-effective than treating the entire stormwater outflow.

In 2006, strict restrictions on using tap water for gardening or car-washing were imposed in Melbourne but relaxed in 2010-2011 as rainfall replenished depleted reservoirs. During this five-year period residents collected their own greywater from washing machines and laundry, showers, baths, and kitchens. The problem with this is that people with diarrhoea and gastrointestinal illness might soil bed linen or clothes, or have an accident in the bathroom, and inadvertently transfer pathogens into the greywater. The worst-case scenario is that greywater containing infectious pathogens is used to water lettuce in a way that transmits infection to those eating unwashed leaves. The Environmental Protection Agency of Victoria (EPAV) published Guidelines (2008) designed to minimise harm to health or the environment. This research examined 1621 households and concluded that although half knew the guidelines existed, they were not following the advice, but nevertheless, although this study was limited, there appeared to be no significant increase in gastrointestinal illness. This research recommended that future housing design incorporate integrated water management strategies to enable safe greywater collection.

Water supply is usually continuous, and interruptions to supply are expensive and inconvenient. Most direct tests for the waterborne pathogens that cause illness are too slow and expensive to be used for the routine monitoring of water safety. Instead, the Hazard Analysis and Critical Control Point (HACCP) system, which was originally developed and implemented in the food industry, has been applied to manage microbiological and chemical contaminants in water treatment plants. This research extended the HACCP approach to water recycling and reclamation processes, by completing a literature review, collating and analysing existing datasets and case studies, conducting a gap analysis, running some pilot trials and preparing three HACCP template plans for use by water utilities, including those in America, when developing their own HACCP systems.

Wastewater often contains endocrine disrupting compounds (EDCs) such as ethinyl estradiol (EE2) which is excreted by women who use some oral contraceptive pills. When wastewater treatment is followed by advanced recycling processes, most of the hormone-like EDCs are removed, but it is possible that these very low levels might still adversely affect health. Giving recycled water to mice will allow examination of these health risks but it is first necessary to develop methods to measure extremely low levels of three forms of estrogen (estrone, estradiol and EE2), as well as progesterone and bisphenol A (BPA), an EDC that leaches out of plastic drinking bottles. This research modified clinical ‘ELISA’ tests commonly used to measure hormones in patient blood samples, and established protocols that allowed the sensitive quantification of five EDCs in recycled water.