Conventional media filtration is the most common process used as one of the main barriers for pathogen and solids removal in water treatment. The Australian Drinking Water Guideline (2011) includes LRV credits for organisms based on treated water turbidity limits. However, the effectiveness of this treatment process in removing pathogens is not typically validated and performance can vary greatly between treatment plants. Hence, understanding the actual LRV performance of media filters is critical to both designing new treatment facilities and understanding any treatment shortfall for existing facilities.

A related protocol for the validation of membrane filters could potentially be adapted for the validation of granular filters. However, the requirements from health regulators, for validation design and safety considerations if surrogate organisms are used, are unknown. The practicality of application in full scale drinking water treatment plants to incorporate any health regulator needs also needs consideration. Therefore, capturing the health policy positions in various Australian jurisdictions and understanding any practical constraints to full-scale validation prior to developing the validation guide are critical to success.

This project will use a progressive approach to determine the regulatory requirements for the validation of drinking water processes, identify any practical constraints for full-scale process validation, and develop a validation protocol or identify further work required to address knowledge gaps or concerns related to the safety or technical feasibility of conducting full-scale validation of granular media filters (to produce drinking water in particular).

This project improved the knowledge of how algae species (population density, morphology and AOM concentration and character) and coagulation conditions (coagulant type, pH, polymer dose, and shear) impact algal floc properties in order to improve the C-F process and downstream separation treatment.

PhD Thesis completed by Andrea Del Pilar Gonzalez Torres in June 2018.

This project aimed to predict the fate and removal of micropollutants during wastewater treatment by the application of fugacity modelling.

PhD Thesis completed by Yufei Wang in September 2017.

The Stormwater Industry Association of Australia (SIA) formulated a draft Stormwater Quality Improvement Device Evaluation Protocol (SQIDEP) proposed for use in validation of stormwater treatment devices. This was presented to some Victorian water industry and regulatory parties for comment in February 2016. The project’s aim was to provide scientific support for the guidance and/or scientifically supported alternative advice.

The purpose of this review was to investigate scientific literature related to stormwater protocols that can add value to the SQIDEP before its official release in 2018. A number of other international stormwater device evaluation protocols were also investigated. A scientifically defensible protocol would add value to the Australian stormwater industry and allow manufacturers and product end users to have confidence in the process used to assess stormwater treatment devices.

Overall a number of recommendations were proposed to improve the Australian-based protocol. These included: increasing the minimum number of storm events; increasing event coverage; reviewing some of the recommended performance metrics; sampling and analysis for suspended total solids, suspended solids concentration and particle size distribution as well as a range of other pollutants; providing target removal levels for suspended solids based on Australian guidelines; sampling some sequential storm events; and inclusion of operation and maintenance requirements and schedules.

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.

People excrete antibiotics and many types of bacteria, and this mixture can become concentrated in wastewater treatment plants. A specific part of the wastewater treatment process, ‘anaerobic digestion’, is particularly associated with the selection, emergence, and growth of antibiotic-resistant bacteria. These scientists want to find out if different ‘anaerobic digestion’ conditions are associated with increases, or decreases, in the numbers of antibiotic-resistant bacteria. They plan to find out by setting up relatively small, bench-sized anaerobic digesters in their laboratory, inoculating them with sludge from a full-scale working digester, then study the effects of different physico-chemical conditions on the incidence and frequency of DNA sequences of antibiotic-resistant genes and the ribosomal RNA sequences commonly used to identify different species of bacteria.

Compliance with the Australian Guidelines for Water Recycling ensures that recycled wastewater does not present a health risk due to infectious pathogens or disease-causing chemicals. Many pathogens in wastewater are inactivated by disinfection treatments such as chlorination, but this causes a problem when disinfectants react with nitrogen compounds in wastewater and form Disinfection By-Products (DBPs), some of which pose a health risk. This research collected samples from four wastewater treatment plants (WWTPs) with different treatment methods and climate zones. A comprehensive and innovative analysis of the types of pathogens, various chemical forms of nitrogen and DBPs, and removal of these components during the recycling process, was related to season, climate and the four different treatment trains. It was concluded that the WWTP using a combined anaerobic/aerobic pond system was best at removing nitrogens and minimising DBP formation, but the best overall treatment performance was delivered by an activated sludge, oxidation ditch and infiltration pond WWTP in a temperate climate. Pathogens were found in influents but not treated effluents, and so were other nitrogen-removing micro-organisms. Treatment was better in summer, and the wastewater quality in these four WWTPs posed a low health and environmental risk to non-potable reuse.

The Australian Guidelines for Water Recycling (AGWR) encompass acceptable health, safety and environmental targets for different types of recycled water. This research begins development of a series of processes that utilities can apply to achieve compliance with the AGWR. This Stage 1 of the project describes six systems for recycling water (natural, managed aquifer recharge, membrane treatment, chemical and photooxidation, biological and adsorptive treatments); six aspects of recycling validation systems which included regulator, utility and technology provider perspectives in different States and jurisdictions, as well as micropollutant risk assessment, instrumentation performance and knowledge transfer, training and capacity building. Current and emerging techniques for scheme validation, and relevant guidelines and case studies were reviewed, and knowledge gaps and core issues were identified. Altogether these were used to develop a ‘National Validation Framework’ and were the basis of a plan for completing Stage 2 (WaterRA project 3018).