The US Environmental Protection Agency has released a preliminary drinking water rule for perchlorate that could set maximum contaminant levels in drinking water at 20, 40, or 80 mu g/L.Perchlorate contamination, often a localized groundwater issue, has been found in Colorado River water as a result of legacy industrial contamination.Perchlorate also forms during the storage of bulk hypochlorite solutions, though it is unlikely to be a driver for change at drinking water utilities.Extensive guidance has been developed from past studies and is summarized here, considering the new preliminary drinking water rule.

Research on drinking water disinfection continues to find both supporting and non‐supporting evidence that trihalomethanes (THMs) and haloacetic acids (HAAs) are causative agents for adverse human health effects such as bladder cancer and that they are appropriate surrogates for reducing adverse health effects through further regulation. The EPA is revising the microbial/disinfection byproduct (M/DBP) rules to further protect public health; however, the decision to change or add regulations is hindered by uncertainty about the causative agents of DBP‐associated risk and the role of compliance strategies to protect public health. Research conducted since the Stage 2 DBP rule was established helps fill some gaps and outlines lingering uncertainties that should be acknowledged as part of revised rulemaking. This thematic review summarizes regulatory implications of the state of the science in epidemiology, toxicology, occurrence/monitoring, and treatment/compliance, and identifies actions toward meaningful regulatory revisions despite ongoing uncertainty of DBP‐associated human health risk drivers.

The U.S. Environmental Protection Agency (EPA) is considering a regulatory revision of the Disinfectant and Disinfection Byproduct Rule (DBPR) with a goal of limiting nationwide exposure to DBPs of emerging health concern. The occurrence of four brominated haloacetic acids (HAAs), which are generally more toxic in in vitro assays than the five currently regulated HAAs and are candidates for future regulation, were surveyed in 4924 public water systems under EPA's fourth unregulated contaminant monitoring rule (UCMR4). Using UCMR4 data, this study evaluated the nationwide occurrence of nine HAA species and the potential for two regulatory scenarios (the mass sum of all nine HAA species, HAA9, or just the six brominated HAA species, HAA6Br) to control nationwide exposure to the most toxic HAAs. Neither HAA9 nor HAA6Br approaches were effective for identifying water systems that exhibit high HAA exposure, assessed as additive cytotoxicity, because they are more specific to the HAA species that form at high concentrations rather than the species that are most toxic. However, the effectiveness of HAA6Br is highly sensitive to the relative toxicity of one HAA compound, monobromoacetic acid, which has the highest in vitro toxicity among HAAs but also the lowest occurrence and about which little is known regarding in vivo health risks. In contrast to HAA9, systems with high HAA-associated additive toxicity tend to share similar treatment and disinfectant characteristics as systems with high HAA6Br concentrations. Systems with high source water bromide and total organic carbon were far more likely to use chloramines as a disinfectant residual compared to other systems, but were no more likely to adopt organic precursor removal technologies (biofiltration, granular activated carbon, and ion exchange) than other systems, on average.

The California Energy Commission funded a study to evaluate two technologies to assess their usefulness as an early leak detection tool for alerting field teams and to better understand the impact on energy savings through managing water loss. Specifically, the latest in advanced correlating continuous acoustic monitoring and satellite imagery leak detection technologies were examined over a period of 12months in the Duarte system of California with 4.9 mgd production capacity and representing several pressure zones in the service area. A key conclusion was that both technologies improved the effectiveness of locating subsurface leaks that would have been invisible to the casual observer, and both were potential candidates for future applications. When implemented together in this study, the two technologies found leaks that would have resulted in between 57-170milgal of lost water during the study period. This equates to 140-419MWh of energy savings in California, amounting to cost savings of at least $100,000 for the Duarte system alone during the 12-month study period.

A redesign, construction, and replacement of the filters used for water reuse at a 11 million gallon per day Florida municipal water reclamation facility provided a prime opportunity to evaluate the impact of the filtration technologies on water quality, trace organic contaminant (TOrC) removal, and removal of pathogens. This study was designed to capture operational data, pathogen removal (Cryptosporidium and Giardia), and TOrC removal before the replacement of the filters using the existing synthetic media filters (SMF) and traveling bridge filters (TBF) followed by an evaluation of the deep bed filters (DBF) after construction and commissioning. The new DBF units provided substantially improved control of turbidity and total suspended solids while also significantly improving the removal of Giardia cysts (increase of >2 log removal) as compared to removal across the older SMF and TBF units and minor improvements to Cryptosporidium oocyst removal. TOrC removal was not significantly changed when comparing removal across the SMF, TBF, and DBF units nor post chlorination (chloramination).

Biological activated carbon (BAC) is widely used as a polishing step at full-scale drinking water plants to remove taste and odor compounds and assimilable organic carbon. BAC, especially with pre-ozonation, has been previously studied to control regulated disinfection by-products (DBPs) and DBP precursors. However, most previous studies only include regulated or a limited number of unregulated DBPs. This study explored two full-scale drinking water plants that use pre-chloramination followed by BAC and chloramine as the final disinfectant. While chloramine generally produces lower concentrations of regulated DBPs, it may form increased levels of unregulated nitrogenous and iodinated DBPs. We evaluated 71 DBPs from ten DBP classes including haloacetonitriles, haloacetamides, halonitromethanes, haloacetaldehydes, haloketones, iodinated acetic acids, iodinated trihalomethanes, nitrosamines, trihalomethanes, and haloacetic acids, along with speciated total organic halogen (total organic chlorine, bromine and iodine) across six different BAC filters of increasing age. Most preformed DBPs were well removed by BAC with different ages (i.e., operation times). However, some preformed DBPs were poorly removed or increased following treatment with BAC, including chloroacetaldehyde, dichloronitromethane, bromodichloronitromethane, N-nitrosodimethylamine, dibromochloromethane, tribromomethane, dibromochloroacetic acid, and tribromoacetic acid. Some compounds, including dibromoacetaldehyde, bromochloroacetamide, and dibromoacetamide, were formed only after treatment with BAC. Total organic halogen removal was variable in both plants and increases in TOCl or TOI were observable on one occasion at each plant. While calculated genotoxicity decreased in all filters, decreases in overall DBP formation did not correlate with decreases in calculated cytotoxicity. In three of the six filters, calculated toxicity increased by 4-27%. These results highlight that DBP concentration alone may not always provide an adequate basis for risk assessment.

The hazard analysis and critical control point (HACCP) process is being widely adopted as a design, control, and operational methodology to maintain the reliability of delivering water quality that is safe for public health. This study applied the HACCP methodology to identify and assess the reliability of critical control points and critical monitors to manage acute and chronic health risks in potable reuse treatment trains. Specifically, a failure analysis was performed for full‐scale ultrafiltration and reverse osmosis critical control points to determine the reliability of critical monitors and their associated impacts on finished water quality. The results supported the use of ultrafiltration and reverse osmosis membranes as critical control points in potable reuse and identified the sensitivities of both current and emerging critical monitoring parameters, including turbidity, total organic carbon, ultraviolet absorbance at 254 nm, conductivity, fluorescence, calcium, sulfate, sucralose, and pressure decay tests.

Granular activated carbon effectively controlled disinfection byproduct formation and calculated toxicity, especially at high influent bromide levels.

This study measured chlorine- and chloramine-reactive precursors using formation potential (FP) tests of nine U.S. Environmental Protection Agency (EPA) regulated and 57 unregulated disinfection byproducts (DBPs) in tertiary-filtered wastewater before and after pilot-scale granular activated carbon (GAC) adsorption. Using breakthrough of precursor concentration and of concentration associated calculated cytotoxicity and genotoxicity (by correlating known lethal concentrations reported elsewhere), the performance of three parallel GAC treatment trains were compared against tertiary-filtered wastewater: ozone/GAC, chlorine/GAC, and GAC alone. Results show GAC alone was the primary process, versus ozone or chlorine alone, to remove the largest fraction of total chlorine- and chloramine-reactive DBP precursors and calculated cytotoxicity and genotoxicity potencies. GAC with pre-ozonation removed the most chlorine- and chloramine-reactive DBP precursors followed by GAC with pre-chlorination and lastly GAC without pre-treatment. GAC with pre-ozonation produced an effluent with cytotoxicity and genotoxicity of DBPs from FP that generally matched that of GAC without pre-oxidation; meanwhile removal of toxicity was greater by GAC with pre-chlorination. The cytotoxicity and genotoxicity of DBPs from FP tests did not scale with DBP concentration; for example, more than 90% of the calculated cytotoxicity resulted from 20% of the DBPs, principally from haloacetaldehydes, haloacetamides, and haloacetonitriles. The calculated cytotoxicity and genotoxicity from DBPs associated with FP-chloramination were at times higher than with FP-chlorination though the concentration of DBPs was five times higher with FP-chlorination. The removal of DBP precursors using GAC based treatment was at least as effective as removal of DOC (except for halonitromethanes for GAC without pre-oxidation and with pre-chlorination), indicating DOC can be used as an indicator for DBP precursor adsorption efficacy. However, the DOC was not a good surrogate for total cytotoxicity and genotoxicity breakthrough behavior, therefore, unregulated DBPs could have negative health implications that are disconnected from general water quality parameters, such as DOC, and regulated classes of DBPs. Instead, cytotoxicity and genotoxicity correlate with the concentration of specific classes of unregulated DBPs.

Granular activated carbon (GAC) adsorption is well-established for controlling regulated disinfection byproducts (DBPs), but its effectiveness for unregulated DBPs and DBP-associated toxicity is unclear. In this study, GAC treatment was evaluated at three full-scale chlorination drinking water treatment plants over different GAC service lives for controlling 61 unregulated DBPs, 9 regulated DBPs, and speciated total organic halogen (total organic chlorine, bromine, and iodine). The plants represented a range of impacts, including algal, agricultural, and industrial waste-water. This study represents the most extensive full-scale study of its kind and seeks to address the question of whether GAC can make drinking water safer from a DBP perspective. Overall, GAC was effective for removing DBP precursors and reducing DBP formation and total organic halogen, even after >22 000 bed volumes of treated water. GAC also effectively removed preformed DBPs at plants using prechlorination, including highly toxic iodoacetic acids and haloacetonitriles. However, 7 DBPs (mostly brominated and nitrogenous) increased in formation after GAC treatment. In one plant, an increase in tribromonitromethane had significant impacts on calculated cytotoxicity, which only had 7-17% reduction following GAC. While these DBPs are highly toxic, the total calculated cytotoxicity and genotoxicity for the GAC treated waters for the other two plants was reduced 32-83% (across young middle old GAC). Overall, calculated toxicity was reduced post-GAC, with preoxidation allowing further reductions.

Increased water scarcity is driving water utilities to consider alternative water supply options (WSOs). Identifying the most sustainable WSOs that meet environmental, economic, and social objectives is challenging due to the overwhelming number of both assessment criteria and treatment configurations, including a growing number of potable reuse options. Conventional approaches using process-based life cycle assessments are data-intensive and site-specific, and therefore not suitable for the early stages of assessing WSOs. To address this gap, we have combined hybrid multi-regional input-output-based life cycle assessment (MRIO-LCA), social impact analysis, and multi-criteria decision analysis (MCDA) to develop a novel, flexible framework with unit process level resolution for the comprehensive evaluation of WSOs. Here we describe the formulation of the framework along with an application to two US utilities considering alternative WSOs. In both cases, given sufficient levels of community acceptance and optimum system design, the results favoured potable reuse WSOs due to their climatic resilience, cost effectiveness and lower environmental impacts (compared to other non-conventional options such as desalination). The generalised and globally applicable framework developed for this study can be used to assess sustainability trade-offs between diverse WSO configurations, providing valuable insights for decision-making processes at the early planning stage, as a complement to existing urban water supply scenario and optimisation models.

A comparison of two applications commonly used to detect cyanotoxinsELISA and LC-MS/MShas the added benefit of providing kinetic data to validate cyanotox V.1.0.

Advanced Oxidation Processes (AOPs) rely on the efficient generation of reactive radical species and are increasingly attractive options for water remediation from a wide variety of organic micropollutants of human health and/or environmental concern.Advanced Oxidation Processes for Water Treatment covers the key advanced oxidation processes developed for chemical contaminant destruction in polluted water sources, some of which have been implemented successfully at water treatment plants around the world.The book is structured in two sections; the first part is dedicated to the most relevant AOPs, whereas the topics covered in the second section include the photochemistry of chemical contaminants in the aquatic environment, advanced water treatment for water reuse, implementation of advanced treatment processes for drinking water production at a state-of-the art water treatment plant in Europe, advanced treatment of municipal and industrial wastewater, and green technologies for water remediation.The advanced oxidation processes discussed in the book cover the following aspects: Process principles including the most recent scientific findings and interpretation.Classes of compounds suitable to AOP treatment and examples of reaction mechanisms.Chemical and photochemical degradation kinetics and modelling.Water quality impact on process performance and practical considerations on process parameter selection criteria.Process limitations and byproduct formation and strategies to mitigate any potential adverse effects on the treated water quality.AOP equipment design and economics considerations.Research studies and outcomes.Case studies relevant to process implementation to water treatment.Commercial applications.Future research needs.Advanced Oxidation Processes for Water Treatment presents the most recent scientific and technological achievements in process understanding and implementation, and addresses to anyone interested in water remediation, including water industry professionals, consulting engineers, regulators, academics, students.ISBN: 9781780407180 (Print)ISBN: 9781780407197 (eBook)

A 10‐month pilot test of advanced oxidation processes helped find the most efficient reuse solution for the city of hollywood to address new florida statutes.

Enzyme-linked immunosorbent assay (ELISA) is an antibody-based analytical method that has been widely applied in water treatment utilities for the screening of toxic cyanobacteria metabolites such as microcystins (MCs). However, it is unknown how the minor structural difference of MCs may impact their chlorination kinetics and measurement via ELISA method. It was found in this study that, regardless of the experimental conditions (n = 21), there was no MC-YR or MC-LY residual, while different removal rates of other MCs were observed (MC-RR > MC-LR > MC-LA ∼ MC-LF) as measured by liquid chromatography tandem mass spectrometry (LC-MS/MS), which was consistent with the relative reactivity of the amino acid variables with free chlorine. The removal of total MCs was generally lower as measured by ELISA than by LC-MS/MS. By incorporating both analytical results, existence of ADDA-containing byproducts or byproducts that had a higher sensitivity toward the ELISA kit was demonstrated, after excluding the contribution of the cross-reactivity of the parent MCs. It should be noted, however, that the cross-reactivities of MCs could be influenced not only by MC congeners, but also by other conditions such as mixtures and the applied ELISA kit.

Extreme weather events have presented significant challenges to drinking water quality managers in Australia and elsewhere. Examples of extreme weather events include droughts, floods, cyclones, and wildfires. With global climate change, an increased frequency and severity of diverse extreme weather events is projected for many parts of the world. As such, the need to effectively prepare for and manage these types of extreme events is increasing. Previous experience with managing water supplies before, during and after extreme weather events can provide valuable lessons to aid planning for future events. By surveying Australian water utilities, detailed experiences and lessons from ten case studies of the management of extreme weather events was compiled. The weather events and their impacts to water quality management are described. The lessons learned from these events were used to establish a series of recommendations intended to be used as guidance for future management of extreme events. An important finding was the need to lead change and coordinate effort by the development of a formal whole-of-organisation strategy for building resilience to extreme events. Effective components of such a strategy include the implementation of a water quality management system and the development of specific incident response plans. The development and maintenance of inter-agency relationships was also found to be important and the use of inter-agency hypothetical scenario testing was identified as an effective way to support this. Strategies identified to assist in maintaining operations during and immediately following extreme weather events include the enactment of incident response plans, effective communication and, where possible, the implementation of short-term risk management controls. Post-event activities were also identified, including event recovery, learning from experiences and knowledge dissemination. The guidance presented in this paper will be of value to water quality managers throughout the world as they plan to enhance resilience within their organisations and services.

CyanoTOX is a spreadsheet tool developed to estimate the removal of extracellular cyanotoxins and help utilities address the complexities of the oxidation of cyanotoxins.