Microbeads derived from personal care products that are introduced to waste water treatment streams and contaminated by persistent organic pollutants are an increasing area of concern for terrestrial and aquatic ecosystems. Two experiments that exposed earthworms to the persistent organic pollutant PBDE were conducted using contaminated microbeads at 100 ng/g and an OECD recommended soil in laboratory conditions for 16 and 21 days to determine if the PBDEs adsorbed to the microbeads were bioavailable to the earthworms. Uptake of most PBDE congeners was found to be statistically significant when compared to the experimental controls in both experiments with the congener uptake resembling trends seen in previous earthworm studies that examined PBDE contamination of biosolid amended agricultural fields.

Honours Thesis completed by Damien Moodie in June 2016.

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.

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.

Wastewater must be treated to remove four classes of pollutants to levels that regulators consider safe for discharge to the environment: these are nutrients, micropollutants, total suspended solids and pathogens. Utilities are granted licenses to discharge based on the performance of their wastewater treatment plants (WWTPs) and legislation-derived guidelines which consider the social, economic, and environmental impacts of wastewater discharge. The problem is that there are substantial interpretative differences between States and jurisdictions. This research established a standard risk assessment framework that provides a transparent method for assessing the relative benefits of different disposal and treatment options, and which can be applied uniformly across Australia.

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 water usually contains extremely low levels of many different chemicals. The Australian Guidelines for Water Recycling (AGWR) require that some of these cannot exceed levels that would pose a risk to health, safety or the environment but there are concerns that one or more of these, or other, unmonitored micropollutants, might present a risk, or that chemicals that individually are harmless might add together and have undesirable effects. This research measured 300 organic micropollutants (listed by the AGWR) in a range of recycled waters and conducted a series of laboratory experiments. It was concluded that the toxic effects of individual chemicals often do add together but that this can be predicted accurately in most cases. Some disinfecting processes used to recycle water produce new micropollutants and it will never be possible to completely analyse the thousands of chemicals in any one water sample. These results led to the recommendation that classical chemical analytical measurement techniques should be complimented by a suite of bioassays which can quantify the total toxicity of all the mixed chemicals within recycled water.

Recycling wastewater by using reverse osmosis (RO) and ultrafiltration appears to be associated with the formation of some groups of micropollutants but there is not much information about these processes. This research selected iodinated disinfection by-products (DBPs) and N-nitrosamines (NDMA), and benzotriazoles and benzothiazoles, which are compounds in dishwasher detergents, for further investigation. It was concluded that minimising the formation of dichloramine (a precursor molecule to NDMA formation) by reducing pH and maximising activated sludge ammonia production, reduced the formation of N-nitrosamines in RO-treated wastewater. Iodinated DBPs and benzotriazoles were detected in RO treated wastewater in this study but at lower concentrations than those thought to pose a risk to human health.

Fish, frogs, and other aquatic animals sometimes show signs of ‘endocrine disruption’; aberrant changes to their hormone or reproductive systems that are thought to be caused by chemicals in the water they inhabit. Very few of these chemicals have been identified, and this prevents the use of classical chemistry-based analytical methods. The other problem is that the levels of hormone-like chemicals which have endocrine-disrupting biological effects tend to be so low that standard chemical methods cannot detect them. This research developed a suite of biological tests sensitive enough to detect very low levels of chemicals associated with certain types of endocrine disruption. These tests were used to examine wastewater, surface water and drinking water collected from Australia, South Africa and four European countries. The water samples were also subjected to standard chemical analysis, and the datasets compared. It was concluded that some wastewater and surface water samples contained compounds that interacted with components of the estrogen, progesterone, androgen and mineralocorticoid hormone systems, but none of the biological tests detected endocrine disrupting activity in drinking water.

The Australian water industry uses a variety of membrane processes to remove unwanted pathogens or compounds, such as salt, from source waters. As membranes age their ability to fulfil these removal and filtering functions declines. The problem is that although there are recognised and validated tests for membrane integrity, they are usually performed only on new membranes, and information about the effect of membrane aging on pathogen removal is limited. This project reviewed published literature and identified four methods suitable for future development as Membrane Integrity Tests that may prove applicable to evaluate aging membranes during ongoing and long-term plant operation.