AWWA water science最新文献

Digital PCR (dPCR) has increasingly been used as a primary measurement method for the characterization of nucleic acid reference materials. Nucleic acid reference materials are particularly useful when used for the validation and calibration of quantitative PCR (qPCR). In this study, we describe the development and characterization of Cyanobacteria DNA reference materials (RM) using dPCR. An international interlaboratory study involving 14 laboratories was conducted using the Cyanobacteria DNA RM in combination with a lyophilized PCR reagent designed for the monitoring of Cyanobacteria bloom events. Of the 55 scored study results obtained using qPCR-based techniques, 62% were within the 8% relative expanded uncertainty based on dPCR measurements, while 100% of the study results returned satisfactory z scores calculated using a set performance coefficient of variation equivalent to one Ct value. The study participants' results indicate that the cyanobacteria DNA RM is fit for the purpose of method validation and quality control of the qPCR format used for monitoring toxic cyanobacteria algae bloom events. Most importantly, the study results demonstrated that the use of standardized reagents combined with highly characterized nucleic acid RMs allows qPCR-based DNA quantification technology to reach levels of accuracy and reproducibility comparable to those achieved with digital PCR technology.

Lithium (Li) is listed on the U.S. Environmental Protection Agency's fifth Contaminant Candidate List (CCL 5), and its occurrence in drinking water is being quantified under the fifth Unregulated Contaminant Monitoring Rule (UCMR5). Little information is available on its removal from drinking water. The current study evaluated 19 historical pilot- and full-scale studies and conducted sampling at 13 water treatment plants. The 32 sites included 3 surface water and 29 groundwater sources, and 8 treatment process categories. Conventional surface water treatment, adsorptive media, biological aerobic groundwater treatment, and manganese removal filters were not effective at removing Li. Cation exchange sometimes achieved Li removal, but removals were inconsistent. Lime softening often removed 11%–54% Li, but treated water Li typically was > 10 μg/L. RO removed > 90% of Li, although finished water concentrations depended on blending rates. This study fills a critical gap in evaluating Li treatability through the existing water treatment infrastructure.

We report an innovative method of extracting water distribution network (WDN) historical repair location data from images of paper repair data maps, to provide usable geo-referenced digitally formatted data. For most water utilities, repair location data typically fall into two eras: pre- and post-GIS, approximately corresponding to pre- and post-2000. Automated conversion of pre-2000 paper maps to a geo-referenced digital format provides additional data to clarify trends in pipe repair causative factors, such as material defects, corrosive or creeping soils, and traffic. We applied the methodology to more than 3,000 maps of the Los Angeles Department of Water and Power WDN, thereby extending the record of repairs backward from 2000 to 1975, almost doubling the number of repair records. The methodology's value, when using the resulting data for analysis, lies in the following: (a) large volumes of hard copy data can now be acquired in an automated manner, saving significant time and effort, (b) specific repair locations are accurately captured, resulting in (c) more reliable, confident, analyses, and results, (d) ongoing problem areas, due to corrosive or creeping soils for example, can be more specifically understood.

Public water systems (PWSs) need robust taste and odor (T&O) methods for a diverse range of compounds to proactively monitor their systems from source to tap and make informed treatment decisions. In this study, Standard Method 6040D T&O compounds by solid-phase microextraction gas chromatography–mass spectrometry was revised to include 19 T&O compounds with various odor descriptors including earthy, musty, grassy, woody, fishy, septic, fruity, and sweet. An interlaboratory comparison was performed to determine method accuracy, precision, reproducibility, and ruggedness. Three laboratories achieved passing quality control (QC) acceptance criteria for all 19 compounds, and one laboratory achieved passing QC acceptance criteria for 14 compounds. In this article, occurrence data and method applications are also discussed, which will allow PWSs to monitor diverse classes of T&O compounds and make informed, proactive treatment decisions to maintain high aesthetic quality for their customers.

This study investigated the adsorption using mixed adsorbents comprising different proportions of commercially available granular activated carbons (GACs) and compared their performance to single GACs for removing algal organic matter (AOM) and pesticides. In addition to diverse GAC ratios, the effects of adsorbent dosage and solution pH were investigated for AOM, pesticides, and an AOM-pesticide mixture. The mixed adsorbents can achieve overall higher removal of AOM and pesticides in a mixture. Surprisingly, even the removal of single adsorbates increased when mixed adsorbents were used. The AOM removal increased from 25%–29% using single GACs to 44% using a suitable adsorbent mixture; similarly, the pesticide removal increased from 52%–67% to 74%. The adsorbent ratio was the key influential factor. Additionally, the pH value also significantly affected the adsorption. Using a mixture of different adsorbents is a promising method for treating drinking water.

Research has demonstrated that water quality degrades in commercial and institutional (C&I) building premise plumbing leading to increased risk to consumers. This study aimed to bridge the gap between real premise plumbing systems and theory by using a pilot scale pipe rig representative of C&I premise plumbing. The research examined changes in key water quality parameters, including chlorine, copper, trihalomethanes (THMs), and cellular ATP (cATP) across different flushing and stagnation conditions. Results indicated significant degradation during periods of stagnation found in real premise plumbing, with reductions in chlorine levels and increases in copper and THM concentrations. Conversely, flushing effectively renewed water quality, though the extent varied with system size and flow dynamics. Correlations were found between key water quality variables. The findings emphasize the need for strategic water management practices to mitigate risks associated with poor water quality in building plumbing systems.