AWWA water science最新文献

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.

Colloidal gas aphrons (CGAs) have proven successful in separating both long- and short-chain PFAS from water; however, little information is available on the impact of surfactants used for aphron generation. This study assesses the use of five cationic surfactant-generated CGAs in batch experiments to remove PFAS from two site groundwaters. The results found that lauric arginate ethyl ester (LAE), a food-grade surfactant used to generate CGAs, had the best performance, removing over 80% of PFAAs in a single stage. Removal rates were consistent between high- and low-concentration waters, indicating its versatility. The addition of a second stage of treatment improved PFAS removal, particularly for short-chain PFAS, as the first stage predominantly removed long-chain PFAS due to their greater presence in the initial water. Higher salinity and saponins reduced the removal rates due to competitive sorption. Overall, the success of a food-grade surfactant for CGA generation is significant in terms of water treatment.

This study produced a comprehensive drinking water ozone-biofiltration evaluation by assessing performance at a newly commissioned facility with varying hydraulic and ozonation operations. In brief, 30 water quality, operational, and biological parameters were collected at 11 locations throughout the treatment train at least every other week for an entire year. Seasonal and environmental variation seemed to influence treatment performance more than operational changes (i.e., ozone or hydraulic re-rating). However, media adenosine triphosphate (ATP), an indicator of biomass, was sensitive to hydraulic variability. Organic carbon was identified as a reliable performance metric, particularly when total organic carbon (TOC) and dissolved organic carbon (DOC) shared a strong linear relationship. Carboxylic acid removal also served as a useful long-term monitoring tool for assessing ozone-biofilter performance. This study establishes a critical benchmark for capturing the effects of intermittent ozonation, variable hydraulic loading, and seasonal transitions that utilities can utilize to better understand ozone-biofiltration processes in drinking water treatment systems.

This study provides a comprehensive evaluation of the effectiveness of 280 nm UV LEDs in enhancing chlorine disinfection in natural water sources. The results of this work indicate sequential treatments (UV-chlorine and chlorine-UV) further enhanced the disinfection efficiency of T1 in natural waters, especially at higher UV doses, such as 40 mJ cm⁻². The log reduction value for the chlorine-UV sequence reached 6.65, slightly higher than the 6.29 for the UV-chlorine sequence, suggesting that sequencing influences disinfection efficacy at higher fluences. UV LED-enhanced chlorine disinfection did not significantly alter concentrations of THMs and HAAs. Overall, the findings of this study open new avenues for the application of UV LEDs in drinking water disinfection, demonstrating their potential as an alternative to traditional disinfection methods. Future research should further explore the effects of UV-chlorine combined treatments under different water quality conditions to optimize disinfection processes and provide theoretical support for innovation in water treatment technologies.

Water distribution systems (WDS) are critical infrastructures essential for human well-being and economic prosperity. However, climate change (CC) is increasingly causing variational environmental stress and natural disasters that threaten the integrity of these systems. Without resilient and sustainable WDS, societies will struggle to function effectively. This review article examines the impact of CC on the integrity of WDS, focusing on physical, hydraulic, and water quality aspects. It presents a synthesis of recently published peer-reviewed journal articles that address these dimensions, while acknowledging their synergistic interrelationships. The paper presents adaptation strategies and highlights utility case studies aimed at strengthening the resilience of WDS against the impacts of CC.

This review introduces a novel risk-based management framework for asbestos cement (AC) pipes in drinking water systems, emphasizing maintenance practices and occupational health risks while harmonizing global regulatory and utility practices. Inhalation risks are well established, but WHO guidance indicates negligible risks from ingestion, not warranting regulatory limits. The framework addresses gaps in fiber release monitoring, standardizing protocols to minimize occupational exposure. AC pipes, deployed since the 1920s, persist in many systems despite phase outs. The study highlights deficiencies in fiber release under varying water corrosivity, advocating management of aging infrastructure through GIS tracking, non-destructive testing (NDT), and phased replacement, informed by case studies from Australia and New Zealand. Airborne exposure underscores the need for standardized protocols. Public engagement and evidence-based decisions are essential where immediate replacement is not mandated. This global synthesis integrates regulatory guidance, utility practices, and health data into an actionable framework.

Gel-type anion exchange (AEX) resin performance is impacted by internal mass transfer, which is represented by the solid-phase intraparticle diffusion coefficient (D_s). Importantly, D_s values are required inputs to ion exchange treatment process models but are rarely reported. Previous experiments using gel-type AEX resins exhibited external mass transfer control, preventing D_s estimation for several anions, including perfluoroalkyl substances. To reduce external mass transfer resistance and allow D_s estimation, a stainless-steel centrifugal stirrer device was standardized and validated with nitrate (model anion). Initially, experiments were conducted across mixing speeds (750–1750 rpm) to balance (1) maximizing external mass transfer and (2) preventing flow disturbances. Subsequently, experiments used an optimized speed to estimate nitrate D_s at multiple initial concentrations on three gel-type AEX resins. The developed methodology was useful for determining nitrate D_s and should enable improved D_s estimates for other contaminants, including perfluoroalkyl substances, needed for ion exchange treatment process models.