AWWA water science最新文献

The occurrence of taste and odor (T&O) compounds in drinking water can lead to public concern about quality when left unaddressed, therefore suitable treatment is needed. This study evaluated the treatability of 18 T&O compounds using chlorine, permanganate, and ozone in MilliQ and river water. Nine T&O compounds showed complete oxidation (>99% removal) in all water matrices by ozone. Most of the remaining T&O compounds were removed to >50% by ozone. Alkalinity, pH, and natural organic matter (NOM) had a significant impact on the decay of ozone. Chlorine and permanganate were ineffective (removal <30%) for 2-methylisoborneol (2-MIB), geosmin, hexanal, pyrazines, and haloanisoles. Although chlorine achieved complete removal for alkyl sulfides and indole, it was only partially effective for aldehydes and ketones. Permanganate was more effective than chlorine in oxidizing unsaturated aldehydes and ketones. Increased NOM and pH reduced oxidation effectiveness for chlorine, but not permanganate.

We used the Delphi method to identify areas of consensus and disagreement in managing building water systems. One hundred and six experts were invited, 25 of whom completed both rounds. More than 95% of experts agreed that current plumbing codes are not adequate and return loop temperature should be monitored. A notably low percentage of experts agreed on the required level of chloramine (i.e., 32%) and flushing frequency (22%), despite these being common control strategies. Consensus was not achieved for temperature and disinfectant residuals, but a plurality of respondents indicated that a temperature of 55°C was appropriate and that low but detectable levels of disinfectant residuals are appropriate. After Round 2, a majority of the experts agreed that the knowledge syntheses provided were helpful and unbiased. Findings from this study will help stakeholders by providing helpful insights on plumbing code, design factors, operational factors, and water quality monitoring practices.

Permanganate can be scavenged by dissolved organic matter (DOM), which decreases microcystin (MC) removal efficiency, and permanganate attack on cyanobacterial cells can damage cells, resulting in the release of additional MCs. Here, the impact of sequential permanganate doses on MC-LR removal in the presence of two DOM isolates (terrestrial- and algal-derived) was examined. Although sequential permanganate dosing reduced the competition for permanganate from each DOM isolate, the overall MC removal efficiency was not as high when multiple smaller doses of permanganate were applied compared to one single dose. Potassium permanganate was not observed to lyse Microcystis cells up to 10 mg L⁻¹. Sequential permanganate dosing did not alter the extent of lysis observed for a model bacterium. Mathematical simulations of permanganate oxidation in the presence of DOM suggested that sequential dosing would be most beneficial for enhancing MC-LR removal when a small portion of highly reactive DOM exists.

Uranium is a regulated contaminant (maximum contaminant level [MCL] 30 μg/L) that contributes to the gross alpha activity of groundwater. The adjusted gross alpha activity (MCL 15 pCi/L) is determined by subtracting the total uranium activity from the measured gross alpha activity. U.S. water utilities can use mass-based and radiochemical analysis methods for compliance monitoring of uranium. Mass-based measurements use a conversion factor of 0.67 pCi/μg of uranium to calculate the adjusted gross alpha activity. This conversion factor assumes that the activity of ²³⁴U equals ²³⁸U. Here, we present two decades of uranium isotope data measured by alpha spectrometry that shows ²³⁴U activity typically exceeds ²³⁸U. Using mass-based measurements, the total uranium activity is biased low causing artificial exceedances of the adjusted gross alpha activity. Therefore, water utilities with gross alpha activities >15 pCi/L should utilize radiochemical analyses for uranium for the most accurate calculation of adjusted gross alpha activity.

Urban centers around the world are grappling with the challenges associated with population increases, drought, and projected water shortages. Potable water reuse (i.e., purification of municipal wastewater for reuse as drinking water) is an option for supplementing existing water supplies. Public perception research on potable water reuse has predominantly employed surveys with multiple-choice questions that constrain survey respondents to describe their concerns by choosing from several response options. This research examines hundreds of write-in responses to a large public survey in Albuquerque, New Mexico, to provide a detailed analysis of residents' questions and concerns about potable water reuse. Findings demonstrate that allowing respondents to voice their actual concerns adds richness and nuance that cannot be obtained from multiple-choice response data alone. Especially with controversial resource considerations, such as potable water reuse, planners would benefit from a full understanding of the problem before engaging with the community.