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The International Water Association (IWA) initiated a Task Force in April 2020 to serve as a leadership team within IWA whose role is to keep abreast and communicate the emerging science, technology, and applications for understanding the impact and the ability to respond to the COVID-19 pandemic and specifically designed for water professionals and industries. Expertise was nominated across the world with the purpose of collectively providing the water sector with knowledge products for the guidance on the control of COVID-19 and other viruses. This review paper developed by a working group of the IWA Task Force focuses on the control of COVID-19. The purpose of this review paper is to provide an understanding of existing knowledge with regards to COVID-19 and provide the necessary guidance of risk mitigation based on currently available knowledge of viruses in wastewater. This review paper considered various scenarios for both the developed world and the developing world and provided recommendations for managing risk. The review paper serves to pool the knowledge with regards to the pandemic and in relation to other viruses. The IWA Task Team envisage that this review paper provides the necessary guidance to the global response to the ongoing pandemic. HIGHLIGHTS Review of existing research of the virus, SARS-CoV-2, that causes COVID-19 and other viruses in relation to wastewater process control and risk mitigation.; Available techniques for wastewater process engineers to reduce health risks associated with COVID-19 within wastewater processes.; Risk mitigation for developing countries that are serviced by small wastewater treatment works.

Water scarcity driven by population growth, lack of conventional supplies, and climate change impacts have resulted in increasing interest worldwide in drinking water augmentation using treated wastewater effluents. Potable reuse can occur indirect or direct, but is also practiced in many places as ‘de facto reuse’, where upstream wastewater discharge occurs to drinking water supplies. With this increasing recognition of potable reuse, there is very limited guidance and standardization for proper design and operation of potable reuse schemes that is protective of public health. This study provided guidance on contemporary approaches for the design, operation, and monitoring of potable reuse schemes, including source water characterization and source control approaches; linking water quality treatment performance goals to health risks; risk mitigation strategies including the design principles of multiple barriers for microbial and chemical contaminants; assessing system reliability and fail-safe design approaches; and, finally, monitoring strategies for process performance and compliance.

Synthetic polycyclic musks (PCMs) Galaxolide (HHCB), Tonalide (AHTN), Phantolide (AHDI), Traseolide (ATII) and Cashmeran (DPMI) are chiral chemicals that are commonly used in washing product industries as racemic mixtures. The major source of PCMs in municipal wastewater is from personal care and household products. Recent studies have shown that PCMs may enhance the relative toxicity of other environmental chemicals by inhibiting cellular xenobiotic defence systems. High sensitivity enantioselective analysis of these compounds enables improved characterisation of the environmental persistence and fate of PCMs, distinguishing between individual enantiomers so that a more complete understanding of environmental risks tributed by individual enantiomers may be obtained. Concentrations of PCMs through the various treatment stages of an advanced water recycling plant in Sydney were investigated to assess the removal of these chemicals. Average concentrations of HHCB, AHTN, AHDI, ATII and DPMI in influent were: 2,545, 301, 2, 5 and 33 ng L−1, respectively. In the final effluent, AHDI, ATII and DPMI were not detected, while HHCB and AHTN were still measured at concentrations of 21 and 2 ng L−1. No significant enantioselective transformation was detected during biological or advanced treatment processes.

Droughts, which are difficult to predict, are a natural feature of the hydrology in most regions. Climate change, however, has the potential to increase the frequency and magnitude of future droughts. While the lack of water availability during droughts is widely publicized, there are equally severe water quality impacts that occur during and after droughts as well. Recent droughts have led to water quality implications for drinking water supplies including turbidity, taste and odor, pathogen concerns, and challenges in managing disinfection byproducts (DBPs). This paper presents the results from a series of case studies prepared for a Water Research Foundation study on the effects of extreme weather on drinking water quality in order to help utilities prepare for vulnerabilities under future climate change. A key finding from the case studies is that droughts can fundamentally alter nutrient cycling and biota within both watersheds and reservoirs that influence water quality for months or years after the event. A few of the critical management actions for responding to degraded water quality related to droughts include awareness of potential impacts, increased monitoring during and after the event, and capacity to quickly adjust treatment processes.

Long range planning for water reuse is very complex due to the interplay of numerous factors. A multi-faceted study was conducted to improve the understanding of these factors, to analyze how different scenarios of the future may affect these factors and water reuse, and to help determine which of these factors and issues are most important to address in order to ensure that water reuse is a successful water supply option in the future. This paper follows a series of surveys, expert workshops and scenario studies that were conducted, with the goal of refining a list of factors and issues that affect water reuse down to a few key items. From this process, the following aspects were concluded to be most important to focus on because they have the most impact, and thus will affect the future of water reuse the most: expanding the perceived role of water reuse; taking action to improve public acceptance; creating a supportive regulatory and legal environment; integrating resource management; expanding economic analysis; considering energy, climate and sustainability issues; creating water reuse institutions and associations; and, encouraging technology advancement and innovation. Discussions of these issues, along with suggestions for further research and innovation are included.

Submerged membrane bioreactors (MBRs) have attracted a significant amount of interest for decentralised treatment systems due to their small footprint and ability to produce high quality effluent, which is favourable for water reuse applications. This study provides a comprehensive overview of the capacity of a full-scale decentralised MBR to eliminate 17 endocrine disrupting chemicals (EDCs) and five indigenous microbial indicators. The results show that the MBR consistently achieved high removal of EDCs (>86.5%). Only 2 of the 17 EDCs were detected in the MBR permeate, namely two-phenylphenol and 4-tert-octylphenol. Measured log10 reduction values of vegetative bacterial indicators were in the range of 5–5.3 log10 units, and for clostridia, they were marginally lower at 4.6 log10 units. Removal of bacteriophage was in excess of 4.9 log10 units. This research shows that MBRs are a promising technology for decentralised water reuse applications.

Natural water treatment systems such as wetlands are increasingly being recognised for their role as part of a multi-barrier system for water recycling. Natural wetland systems have the ability to provide effective treatment for a wide range of organic chemicals. However, techniques are required to validate the performance of these treatment processes in the field. This paper provides a new method for evaluating wetland systems using passive samplers and applies a statistical method for use in advanced water treatment processes. Three years of stormwater quality passive sampler data for diuron, simazine and atrazine is provided to determine herbicide removal between the inlet and outlet regions of a constructed wetland. Mean removal rates over the three year period for diuron, simazine and atrazine were 43, 54 and 50% respectively. The results show that this method coupled with passive samplers is amenable to wetland system barrier characterisation where opportunities for process validation is not feasible.

Advanced water treatment plants employing ultrafiltration (UF) and reverse osmosis (RO) membrane processes are frequently implemented for the production of high-quality recycled water. It is important that process performance is able to be quantified and assessed to ensure it is fit for purpose. This research utilizes size exclusion chromatography with organic carbon, organic nitrogen and UV254 detection to determine the change in both DOC concentration and character through a UF/3 stage-RO pilot plant. It was determined that 97% of the influent DOC was removed on average to produce a water of less than 0.5 mg L−1 as C. The UF process removed more than half of the biopolymer fraction, equating to 4.5% DOC removal, while the RO process generally removed all DOC except a small proportion of the low MW humics and acids and low MW neutral fraction. While not changing significantly in concentration, the Stage 3 RO permeate typically contained low concentrations of humic fraction, indicating a change in character and therefore a change in rejection mechanism. Overall, it was determined that while TOC monitoring is important in advanced water treatment systems, improved understanding of the character of the TOC present lends greater insight into the assessment of process performance.

The concentrations of some important endocrine disrupting chemicals and pharmaceuticals after various stages of wastewater treatment were investigated. The endocrine disrupting chemicals included natural and synthetic estrogenic and androgenic steroids. The pharmaceuticals included a series of sulfonamide antibiotics and trimethoprim. The removal efficiency of a membrane bioreactor (MBR) was investigated and compared with a conventional activated sludge (CAS) system. Samples were analysed by liquid chromatography tandem mass spectrometry. Results showed that the MBR and CAS systems effectively removed steroidal estrogens and androgens, but only partially eliminated the target antibiotics from wastewater. The MBR was shown to be more effective than the CAS system which was possibly attributed to the high solid retention time and concentration of biosolids in the MBR. The results highlight the potential wider application of MBRs for the removal of trace chemical contaminants in wastewater and their potential for use as decentralised wastewater treatment systems.

Fluorescence excitation-emission matrix (EEM) spectroscopy was used to distinguish between two stages of reverse osmosis (RO) permeates as the first step towards investigating the potential application of fluorescence as a monitoring tool for membrane performance. The signal response of several fluorescence peaks present in Stage 1 and Stage 2 RO permeates of an advanced water treatment plant were compared. The humic-like fluorescence region was found to have the largest percentage difference between stages and therefore was the most appropriate for enabling differentiation. Increases in humic-like fluorescence did not correlate with increases in conductivity or dissolved organic carbon measurements. This suggests that fluorescence is a more selective and sensitive method for monitoring the organic composition of RO permeates than established methods. Fluorescence is therefore a promising tool for improved water quality monitoring of RO permeates.

Ozone treatment of drinking waters has been applied for a range of purposes including taste and odour control, inactivation of protozoan parasites, degradation of cyanotoxins, ‘enhanced coagulation’, ‘enhanced biodegradation’ and oxidative degradation of recalcitrant organics. Molecular ozone reacts at unsaturated sites of natural organic matter (NOM) to produce smaller oxygenated molecules including carbonyl compounds such as aldehydes, ketones, and carboxylic acids. The elucidation of the nature and precise identity of these ozonation by-products is hindered by two complicating factors. The first is the inherent aqueous solubility of many of these compounds, which renders their efficient extraction from water difficult to achieve. Second is the lack of established identity of specific potential by-products, which complicates targeted analytical approaches. To address these challenges, we have approached the task of by-product identification by methods involving aqueous functional group-specific derivatisation reactions. A range of carbonyl byproducts were identified during laboratory-scale testing. These ranged in size from formaldehyde up to 7-carbon species with multiple carbonyl and hydroxyl functional groups.

The risk of endocrine disrupters to humans and wildlife is to date poorly understood, although evidence of effects is now widespread. In understanding the risk, an important step is the determination of the partitioning, as well as chemical and biochemical transformation, of compounds in the environment, the water cycle and the food chain. This is a complex task and this paper is a first step towards estimating some of these factors from a largely theoretical approach. A chemical fate model is used to predict the fate of the contraceptive drug 17α-ethinylestradiol (EE2). The example of the contraceptive pill is chosen to follow the journey of the drug from human ingestion and excretion to treatment in a sewage treatment plant (STP) using fugacity-based fate models, followed by discharge into a receiving river and eventually into the estuary/sea. The model predicts how EE2 will partition into the different compartments during each stage of this journey and thereby infiltrate into the food chain. The results suggest that a person would have to ingest more than 30,000 portions of fish to consume an equivalent to a single average dose of the contraceptive pill. While this scenario is highly unlikely, the biochemical consequence of the contraceptive pill is greatly significant. Furthermore, there are many identified similarly estrogenic compounds in the environment while this study only considers one. Cumulative effects of such compounds as well as degradation into other potent compounds may be anticipated. An important message in this paper is the interrelation of wastewater effluent discharge and eventual human exposure of marginally degradable and lipophilic chemicals. While at present the main concerns regarding endocrine disrupters appear to be the fear of their occurrence in drinking water sources, it is clear that the domains of wastewater treatment and discharge, water supply and contamination of food should not be treated as separate issues. The model suggests that exposure from food (contaminated by effluent) may be much more significant than from drinking water. Keywords Endocrine disrupting chemicals; fugacity modelling; wastewater treatment

A general procedure was developed for estimating the concentrations of pharmaceutical residues in fresh primary and secondary sewage sludge. Prescribed quantities coupled with information on the various excretion ratios of 20 pharmaceuticals and 2 of their metabolites enabled prediction of the overall rates of excretion into Australian sewage. Fugacity modelling was applied to predict concentrations of these residues in fresh primary and secondary sludge. Predicted concentrations ranged from 10−3 - 884 μg/L in primary sludge and 10-4 - 36 μg/L in secondary sludge. Overall rates of removal to sludges ranged from 1-39%. The accuracy of the model was verified by comparison to analytical data.

Most households regularly use products containing trace organic compounds (TOrC), including endocrine disrupting compounds (EDCs) pharmaceutically active compounds (PhACs), personal care products (PCPs), and household chemicals (HHCs), which ultimately end up in municipal wastewater treatment systems. These emerging TOrC are of concern due to the increasing number of reports of reproductive disorders in aquatic wildlife residing below wastewater outfalls and the continuous creation of new synthetic TOrCs, which precludes comprehensive testing for all potentially toxic compounds. In order to assess the exposure of these compounds into the environment there is a need to evaluate their removal within conventional wastewater treatment systems. The near impossibility of experimentally studying the fate and transport of current and future emerging contaminants on an individual basis indicates a need to develop a tool which quickly provides guidance on how effectively certain compounds are removed during wastewater treatment. This tool would provide utilities the ability to quickly screen an organic compound of concern and provide a meaningful response in regards to exposure assessment. Quantitative structure property relationships (QSPRs) are useful and powerful tools for quickly screening the environmental fate of emerging contaminants and assessing their removal within treatment systems. However, an evaluation of existing QSPR models applicable for wastewater removal mechanisms is lacking. This title belongs to WERF Research Report Series . The objective of this study was to evaluate existing QSPRs for predicting the partitioning of a TOrC between the aqueous and solids phases during primary and activated sludge treatments and the transformation rates of a TOrC during biological activated-sludge and chlorine oxidation treatments. To address the overall objective the following three tasks were accomplished: ISBN: 9781843393344 (eBook)