Waterborne pathogens cause millions of people to be sick each year globally, putting a burden on hospitals and having financial implications. This research aims to identify the waterborne pathogens at the point of need, sample collection sites, water plants, treatment plants, water quality check points and drinking water quality assurance etc. The research outcomes will inform best practice for clean drinking water supply to the community thus improving public health and wellbeing.

PhD Thesis underway by Alka Rani.

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.

Source waters contain a class of chemical compounds collectively known as ‘bromides’. Standard water treatment includes chlorination; a process designed to kill harmful microorganisms in source and recycled waters. The problem is that chlorination agents react chemically with bromides to form ‘brominated Disinfection ByProducts’. These bDPBs can contribute to the development of cancer and this led the Australian Drinking Water Guidelines to recommend very low concentrations of bromides in source waters, less than 0.1 parts per million (0.1mg/L). At this level, if any bDBPs subsequently formed during chlorination, their occurrence will be too low to pose a public health risk. Some Australian source waters have higher bromide concentrations, but existing removal methods are expensive and/or do not work very well. The scientists in this team have already synthesised a new bismuth substance (see image) that removed 86% of an experimental bromide from artificial groundwater.

This project will aim to combine the modified bismuth with alum, which is currently used to treat water. If researchers succeed in creating a composite that incorporates bromide removal into existing tried-and-tested water treatment processes they will deliver a cost-effective improvement to water quality and safety. However, it will require clever and careful chemical design to create the new bismuth-alum composite, and to run experiments that will test its ability to remove bromides from source waters. As if that isn’t challenging enough, they also propose to develop a software programme that will predict bDBP formation. If they are able to eventually build a validated model it will be an extremely useful addition to the suite of tools currently used to produce safe, high-quality drinking water.

N-nitrosodiumdimethylamine (NDMA) in drinking water is one of many factors – such as a persons’ genes – that cause cancer. Although NDMA is not a sole cause of cancer, the water industry aims to minimise its contribution to illness and disease. This research measured levels of NDMA in drinking and recycled waters and found the majority well below the Australian Drinking Water Guideline values that are considered safe for public consumption. Different sources of NDMA were identified and water monitoring and treatment strategies to optimise NDMA removal from source waters were recommended.

The standards for recycling stormwater are higher for drinking water than for non-potable reuse such as agricultural or urban irrigation. The Australian Drinking Water Guidelines (ADWG) inform regulations that ensure the removal of infectious pathogens and polluting chemicals from potable water, whereas the Australian Guidelines for Water Recycling (AGWR) ensure that non-potable recycled water does not pose a risk to human health. Compliance with these Guidelines often requires quantitative risk assessment of stormwater catchments, but this is an expensive and resource-intensive process. This research developed a ‘Chemical Hazard Assessment of Stormwater Micropollutants’ (CHASM) desktop tool to assess the suitability of stormwater for various potable and non-potable uses before commencing an expensive risk assessment, and to guide design of optimal and targeted monitoring and measuring programmes for chemicals of concern in any given catchment. Basic information about each of four Australian stormwater catchments (including size, land-use, and surface types) was entered into CHASM Excel spreadsheets. The tool utilises a database to generate a list of likely pollutants for that catchment, and optimal locations and times for monitoring. The CHASM tool proved reliable and easy to use.

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.