The presence of taste and odour (T&O) is a growing concern for the water industry due to negative associations with unsafe drinking water. Although consumers primarily judge water quality by its aesthetic properties, T&O compounds are usually present in trace concentrations. This project investigated current complaint management processes and evaluated analytical techniques for detecting T&O compounds.

Honours Thesis completed by Lily Liu in June 2015.

This project investigated the relationship between disinfection by-product (DBP) formation in drinking water and the molecular weight distribution of its natural organic matter precursors (NOM) to help increase our understanding of how NOM properties such as size, aromaticity and structure affect DBP formation and toxicity of the formed DBPs.

Honours Thesis completed by Sophie Day in 2012.

This project provided an on-line monitoring protocol utilizing fluorescence to aid utilities in their provision of safe drinking water thus addressing the National Research Priority Goal “Water – A critical resource”

PhD Thesis completed by Yulia Shutova in October 2014.

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.

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.

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.

There are concerns that recycled wastewater used for watering gardens or washing cars might be accidently ingested. The problem with this is that water for irrigation is not recycled to the same high (and expensive) standard as potable drinking water and might contain pathogens that cause diarrhoea and illness. Recycled water providers must quantify the risk that irrigation water might pose to public health, even though it is not supposed to be drunk. This research worked on the first part of this health risk quantification problem by developing a method to measure the amount of water a person might ingest while, for example, washing a car. Harmless cyanuric acid is commonly added to swimming pools and swimmers often ingest pool water. The amount of cyanuric acid measured in their urine is related to the volume of pool water they ‘drank’. Domestic users of recycled water are more likely to ingest less recycled water than swimmers, so a more sensitive ‘GCMS’ method for measuring very low levels of cyanuric acid was developed. It was shown to work after cyanuric acid was added to water, drunk by three adult volunteers, and then measured in their urine.

Recycling wastewater to a standard that makes it fit for use in irrigation is an efficient and cost-effective strategy for managing water resources, and has prompted the installation of separate pipe and tap reticulation systems in domestic housing schemes such as at Rouse Hill in Sydney. The problem is that water used to irrigate gardens and parks is not recycled to the same high (and expensive) standard as potable drinking water. This makes it important to monitor the drinking water to ensure that it is not accidently contaminated with slightly lower standard irrigation water. This research showed that an inexpensive 4-electrode sensor reliably detected changes in electroconductivity and ultra-violet fluorescence that corresponded to only 1mL of recycled water leaking into 9mL of drinking water. It is likely that a real-world installation of one sensor by the inflow pipe for the housing scheme and multiple sensors by household taps will be even more sensitive. It was concluded that R&D should continue in a larger-scale trial to monitor drinking water quality in dual reticulation systems.