Biosolids generated during the wastewater treatment processes has become a major burden of wastewater treatment plants and an unresolved problem for major cities around the world. It is thus imperative to identify a sustainable way for the proper management of biosolids. The overarching aim of this research is to establish a robust assessment framework to estimate the environmental sustainability implications of different pathways for biosolids processing and resource recovery in an Australian context and provide information to decision makers and practitioners of the water industry on the performance of different treatment scenarios.

PhD Thesis underway by Jingwen Luo.

As there is lack of understanding the roles of sampling methods on measuring for volatile gas sampling from biosolids, it might cause various concern about what are we really measuring. This project aims to understand the influence of sampling methods on emission produced in Wastewater Treatment Plant, especially from biosolids. This research will inform a best practice for sampling devices, regarding the research purpose, sample types, analytes will be proposed. By addressing the potential limitations and influences of different sampling methods on emission measurement, better practice for pollutant management and resource recovery of biosolids can be achieved.

Thesis underway. 

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.

Detection of Algal and Cyanobacterial blooms have increased in lakes, rivers and reservoirs over the last two decades. This hampers drinking water treatment processes due to the high cell numbers and the release of algal organic matter that comprises toxins and taste and odour compounds. This project examined the in-depth potential of in situ fluorometers to improve early warning of bloom development via the analysis of fluorescent cell pigments to give an estimate of cell biovolume.

PhD Thesis completed by Sara Imran Khan in March 2019.

Sunlight-induced degradation is an important removal mechanism for some contaminants and has been commonly overlooked as a removal mechanism in wastewater systems in the past. This project aims to predict the direct sunlight-induced degradation, or direct photolysis, of contaminants of emerging concern in wastewater treatment lagoons to improve monitoring and removal efficacy of the contaminants, and thereby enable water operators and management to perform ecological risk assessment and make better management decisions.

Honours Thesis underway by Michelle Um.

This project will use granular activated carbon to remove algal metabolites. Adsorption and biodegradation of algal metabolites will be monitored and modelled in the laboratory and at pilot scales, with the aim of guaranteeing safe and cost-effective drinking water treatment.

Raw source water contains parts of plants, blue-green algae and their toxins, and many other types of organic matter. Identifying the types and amounts of organic matter helps treatment plant operators make informed decisions about the most efficient and cost-effective methods for treating and removing unwanted substances from source waters. The problem is that many of the tests for identifying organic compounds can take hours to days to deliver results. This research developed a test that gives information immediately. It uses three commercially available fluorescent probes that each emit fluorescent light at a specific wavelength. Certain compounds within organic matter, such as proteins, “reflect” the fluorescent light, but at different wavelengths which can be detected by the probes. These patterns of “reflected” fluorescence were related to traditional tests for organic compounds. This on-line fluorescence monitoring was then trialled at real-world treatment plants. The patterns gave reliable information about broad categories of organic compounds and there was a linear correlation between dissolved organic carbon and fluorescent intensity in both raw and treated waters. This research has provided a valuable addition to the suite of tools available for producing safe, high quality drinking water.

Wastewater, including sewage, must be treated to remove chemical pollutants prior to its release into the environment. Sunlight can degrade polluting contaminants when wastewater is held in large, shallow lagoons. This research will examine the effectiveness of sunlight for reducing pollutants, and how sunlight interacts with substances in water to generate ‘photochemically produced reactive intermediates’, which cause indirect degradation of contaminants. The rate at which light-derived ‘reactive intermediates’ damage selected contaminants, and information about the molecular structure of the contaminants, will be combined to build a conceptual model that can be used to predict future photolysis and contaminant removal in wastewater lagoons.

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.