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Door Hangers and Incentives Induced Little Participation in Lead Water Pipe Inspections
Gazze L., Klemick H., Parthum B., Wolverton A.
Q1
ABSTRACTThe Environmental Protection Agency has finalized regulations to require water systems to replace millions of lead pipes with safer alternatives for carrying drinking water into U.S. homes. Before replacing them, water systems must identify where these lead service lines are located due to incomplete inventories. We conducted a randomized controlled trial to evaluate an intervention that targeted properties with unknown pipe material in Trenton, New Jersey—a community with older housing stock and a high concentration of people of color, renters, and households experiencing poverty. The intervention included two treatments: door hangers with information about a self‐inspection process that allowed residents to submit a photo of their service line, and similar door hangers offering gift card incentives upon submission of a self‐inspection. These treatments had null or small effects on residents' participation in self‐inspection. Under 1% of treated addresses participated in a self‐inspection, including those offered the highest incentive of $100.
Interlaboratory Performance Study of Cyanobacteria DNA Reference Materials Using a qPCR Format for Monitoring Cyanobacterial Blooms
Pinheiro L.B., Van Asten M., Antin L., Adams H., Qiu J.Y., Robinson M., DeLorenzo S., Holmes R., Hurd M., Tang R., Clausen K., Greenwood K., Sudhi R., Wright P., Steiner K., et. al.
Q1
ABSTRACTDigital 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.
Automated Acquisition of Historical Water Distribution Pipe Repair Location Data
Scawthorn C., McGlinchy J., Porter K.
Q1
ABSTRACTWe 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.
Understanding the Cost of Basic Drinking Water Services in the United States: A National Assessment
Hughes S., Kirchhoff C.J., Lee M., Switzer D.
Q1
ABSTRACTThe cost of basic drinking water services has implications for affordability, investment capacity, and public health. The fragmentation of drinking water services in the United States makes it difficult to reliably track and compare what customers pay for basic drinking water services. This paper uses a new, national dataset to examine the social, political, environmental, and institutional drivers of the cost of basic drinking water services, measured as the cost to households of 6000 gal of water per month. We find basic drinking water service costs vary widely across the United States. Costs are generally higher in smaller and more liberal cities and lower in places that rely on groundwater sources. Our findings provide a unique national perspective on variation in, and drivers of, the cost of basic water services and can inform efforts to improve the affordability, accessibility, and quality of drinking water services in the United States.
Mixed Adsorbents: Synergic Effects Improve Problematic Compounds Removal During Drinking Water Treatment
Sichrova K., Cermakova L., Novotna K., Pivokonska L., Zustakova V., Pivokonsky M.
Q1
ABSTRACTThis 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.
Pilot‐Scale Analysis of Stagnation and Flushing in Premise Plumbing
Hogue D., Steele M., Boyer T.H.
Q1
ABSTRACTResearch 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.
Method Development, Interlaboratory Comparison, and Occurrence Study for 19 Taste and Odor Compounds by Solid‐Phase Microextraction Gas Chromatography–Mass Spectrometry
Adams H., Reeder S., Kohoutek K., Hoppe‐Jones C., Pochiraju S., Southard M., Ikehata K., Espindola C.A., Dietrich A.M., Burlingame G.A., Nix D.K., Marfil‐Vega R., Jeffers T., (Mel) Suffet I.H., Ashman M., et. al.
Q1
ABSTRACTPublic 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.
Robustness and Related Concepts for Climate Adaptation in Drinking Water Treatment Systems
Nemani K.S., Peldszus S., Huck P.M.
Q1
ABSTRACTClimate change intensifies extreme weather events, potentially posing significant challenges to the quality and quantity of surface water available for drinking water treatment. Quantifying and substantiating a treatment system's capacity and vulnerability in handling a range of raw water conditions is crucial for preparing for future climate scenarios. Concepts like resilience and reliability and related tools have been applied to drinking water treatment plants (DWTPs), but often fail to capture the operational boundaries of treatment processes. Robustness offers a complementary approach, focusing on the range of conditions a system can effectively manage, thereby laying the foundation for improving the system and thus bridging a critical gap in adaptation strategies. This review examines the interconnections between robustness, resilience, reliability, risk, and vulnerability, providing tailored definitions for DWTPs. It also introduces visual diagrams to further illustrate their link and collective role in climate adaptation planning.
Lithium Removal From Drinking Water
Keithley A.E., Jordan P., Muhlen C., Pinelli M., Lytle D.A.
Q1
ABSTRACTLithium (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.
Drinking water buffer intensity simulator (BIS): Development and practical simulations
Wahman D.G., Schock M.R., Lytle D.A.
Q1
AbstractAn established body of research over many decades has identified the importance of both bulk‐water and pipe scale surface microenvironment buffering to meet distribution system pH targets and reduce corrosivity toward metallic piping and components. Buffer intensity quantifies the ability of water to resist pH changes, and the greater the buffer intensity, the more resistant the water is to pH changes. To provide a practical tool for exploring buffer intensity, a buffer intensity simulator (BIS) was implemented in open‐source R code, incorporating typical chemical species (e.g., carbonate and orthophosphate) that contribute to drinking water buffer intensity along with temperature and ionic strength impacts. The BIS was verified against a parallel spreadsheet implementation and is publicly available at https://github.com/USEPA/BIS. Simulations were conducted to illustrate impacts related to buffer intensity using three practical scenarios: carbonate buffering in drinking waters, temperature impacts, and free ammonia presence from chloramine use and/or source water presence.
The role of genus Bacillus in biodegradation of microcystins: Implications for the removal of cyanotoxins from tropical freshwaters
Wijesooriya M.M., Masakorala K., Kumari W.G.
Q1
AbstractThe proliferation of harmful cyanobacterial blooms poses a threat to the ecosystem and human health. Microcystins (MCs) are the most frequently detected cyanotoxin released by cyanobacteria, including Microcystis sp. Our study aimed to isolate potential MC‐degrading bacteria in Sri Lankan freshwater and determine their possible MC‐degradation pathways. Twenty‐two morphologically distinct bacterial strains from 13 freshwater bodies were isolated following the enrichment assay. MC‐biodegradation assays further confirmed the MC‐degradation potential of 21 strains, with Bacillus being the predominant genus. The strain Bacillus altitudinis BL1, isolated from Beira Lake, showed the highest efficiency in Microcystis sp. cell lysis (80%) and MC‐degradation (87%). PCR assay results confirmed the absence of mlrABCD genes in all strains, indicating the presence of uncharacterized alternative MC‐degradation mechanisms that require further exploration. The dual functions of Microcystis sp. cell lysis and MC‐degradation in 21 strains support developing efficient bacteria‐mediated strategies to remediate microcystins and eradicate Microcystis‐blooms in tropical freshwaters.
A pilot‐scale study of potable reuse impacts on surface water treatment
Seshan H., Adelman M.J., Russell P.J., Quicho J., Daft D., Watson T.
Q1
AbstractInterest is growing in direct potable reuse where advanced‐treated water and raw water are blended and fed directly to a water treatment plant (WTP). However, the impacts of raw water augmentation on treatability at drinking water treatment plants have not been studied extensively. A pilot‐scale treatment system, consisting of coagulation, flocculation, sedimentation, and filtration, was set up at a WTP to treat potential future blends of advanced‐treated water and current raw water. The pilot plant was run with blends from 20% to 100% advanced‐treated water at a range of filtration rates (2–9 gpm/sf) and coagulant doses. Under all conditions, filterable water was produced, achieving acceptable turbidity removal. Turbidity removal by sedimentation was variable (30%–90%). Filtration performance was more consistent, exceeding 90% turbidity reduction under all conditions and achieving lower headloss accumulation rates at higher advanced‐treated water share. These results are optimistic for potable reuse schemes featuring raw water augmentation.
Impact of flocculated and softened particles on UV254 inactivation of indigenous spores
Straathof J., Bohrerova Z., Hull N.M.
Q1
AbstractUS regulatory ultraviolet (UV) disinfection credit is typically granted when turbidity is ≤1 NTU. However, studies show turbidity does not always correlate well with UV dose responses. This study examined the impact of worst‐case high turbidity scenarios at drinking water treatment plants on UV254 inactivation of indigenous spores from unfiltered source water and unsettled flocculation and softening steps. Flocculated water (turbidity = 6.49–164 NTU) had the lowest dose response with a significantly lower Geeraerd‐tail maximum inactivation rate (kmax = 0.021 cm2/mJ) and higher residual population density (Nres = 7.081 SFU/mL). Raw source water (kmax = 0.027 cm2/mJ, Nres = 1.168 SFU/mL, turbidity = 0.978–215 NTU) and softened water (kmax = 0.030 cm2/mJ, Nres = 0.216 SFU/mL, turbidity = 318–495 NTU) had similar dose responses despite significantly different water quality. Particle size and the degree of particle‐associated spores best explained the differences in dose responses. Almost all spores were associated with flocculated particles instead of free‐floating, which increased tailing and negatively impacted UV inactivation. Based on regulatory reduction equivalent dose bias factors and UV sensitivities of spiked Bacillus subtilis spores, Cryptosporidium would be 4‐log inactivated in these raw, flocculated, or softened waters if UV transmission were ≥65%, 90%, or 80%, respectively, even though turbidity was grossly >1 NTU. Depending on particle characteristics, partial inactivation credit when turbidity is >1 NTU should be considered to avoid high‐tier violations while still protecting public health.
Lithium in drinking water: Review of chemistry, analytical methods, and treatment technologies
Korak J.A., Brandhuber P.J., Goodwill J.E.
Q1
AbstractLithium was included in the fifth Unregulated Contaminants Monitoring Rule, signaling the Environmental Protection Agency's interest in regulating lithium. Many questions regarding occurrence, health effects, and treatability of lithium exist. This review primarily focuses on the relationship between lithium chemistry and treatability. Sampling indicates nationwide lithium occurrence in drinking water. Yet, lithium is not included in the Integrated Risk Information System, reflecting a lack of censuses regarding its health effects. Aqueous lithium is a monovalent cation with size, charge density, and solubility properties that present treatment challenges. Lithium's growing economic value is stimulating new extraction and isolation technologies, but these may not be transferable to drinking water treatment. Currently, reverse osmosis is the only full‐scale drinking water treatment technology that can reliably remove significant levels (>50%) of lithium. Focusing future research efforts on electrodialysis and inorganic ion sieves may yield significant gains in effectiveness and readiness for the drinking water industry.
2015 United States Public Health Service optimal fluoride level adherence and operation among adjusting water systems in 40 states: 2016–2021
Boehmer T.J., Hamilton E.K., Lesaja S., Thomas B., Espinoza L., Kaufmann R., Ladva C.N.
Q1
AbstractIn 2015, the United States Public Health Service (USPHS) set a target fluoride level for drinking water at 0.7 mg/L to maximize oral health benefits while minimizing any potential harms. Using water fluoridation operational data reported by water systems to the Centers for Disease Control and Prevention (CDC) Water Fluoridation Reporting System (WFRS) during 2016–2021, this study assesses how water systems performed around this target. The authors summarize completeness of data reporting, assess the distribution of monthly average fluoride readings (MAFR) values, and evaluate precision in maintaining fluoride levels. About 69% of adjusting systems provided data, with an average completeness of 63.8% among them. MAFR mean was 0.71 mg/L (SD: 0.20 mg/L), indicating that water systems have primarily adopted the USPHS target. About 76% of MAFRs fell ± 0.1 mg/L around the reporting system point's mean, indicating feasibility in maintaining precision around a target. State programs and water systems could work together to improve data quality and educate operators on best practices.
Rejection of low‐molecular weight neutral organics is highly sensitive to reverse osmosis system design and operation
Howe K.J., Hernandez‐Quintero J.P., Lee C.O.
Q1
AbstractA computational model was developed to investigate the significance of system design and operating conditions on the rejection of neutral, low‐MW organics by reverse osmosis for potable reuse. The model demonstrated that the decrease in local rejection as net driving pressure decreases is substantially greater for moderately rejected compounds than for highly rejected compounds. At recovery values less than 70%, the local permeate concentration can exceed the pressure vessel feed concentration for moderately rejected compounds. System‐level rejection of moderately rejected compounds is likewise substantially more sensitive to operating conditions than highly rejected compounds. The findings highlight a drawback of relying on rejection results from bench‐scale testing that operates at low recovery, which invariably has higher rejection than full‐scale systems operating at similar pressure. The analysis demonstrates a trade‐off in which the low‐pressure, high‐recovery operation desired for potable reuse systems can be detrimental to the removal of low‐MW neutral organics. The removal of low‐MW neutral organics can be improved if organics rejection is explicitly evaluated during the design process.
Repeated conventional flushing to improve water quality in a full‐scale distribution system
Vedrin M., Eisenberg J.N., Page S., Lahr R., Steglitz B., Hardin R., Raskin L.
Q1
AbstractOne of the primary ways utilities prevent and address water quality concerns in distribution systems is via regular hydrant flushing, yet rigorous research to evaluate the impact of full‐scale flushing programs is limited. This study employed time‐series and correlation analyses to evaluate the efficacy of a utility's five‐month repeated conventional flushing program to reduce nitrification and improve disinfectant residual concentrations in the distribution system. Short‐term water quality improvements during flushes were common across the 16 locations flushed, but lasting improvements were inconsistent as demonstrated by continued nitrification and heterogeneous water quality changes. Flushing frequencies and flow rates may need to be tailored to individual sites, even when similar water quality challenges exist. Water quality monitoring data and related analyses helped to prioritize flush sites, maximize efficiency during and between flushes, and inform decisions to implement additional interventions.
The use of lead isotopes for determining sources of lead in drinking water
Cornwell D.A., Kamenov G., McTigue N.E.
Q1
AbstractA series of paired samples were analyzed to determine if high‐precision lead isotopic fingerprinting could help identify the source of lead in plumbing materials and drinking water. Samples were obtained of plumbing materials (lead service lines, copper pipe with lead solder, galvanized materials, and brass fixtures) from water utilities across the United States. Lead samples were taken from the material itself, from scales, and in some cases from associated water. The lead samples were analyzed to determine the ratios of the four stable lead isotopes present. The results enabled the identification of relationships between various components and further aided in the identification of the source of lead found in water and in pipe scales. Isotopic fingerprinting, as demonstrated in this study, could be used to determine if a galvanized line is a galvanized line requiring replacement (GRR) under the Lead and Copper Rule Improvements (USEPA, 2023).
Chlorine conversion impact on activated carbon block filters: Water quality and nitrification risk in chloraminated water
Jakpa H., Alfredo K.
Q1
AbstractThe effectiveness of a periodic free chlorine conversion period (FClP) as a nitrification mitigation measure has been scrutinized in chloraminated distribution systems, and knowledge about the response of activated carbon block (ACB) point‐of‐use (POU) filters to this practice is unknown. In this study, three similar filters were monitored bracketing three successive FClPs in the laboratory, aimed at studying the response of ACB POU filters to FClP and the occurrence of nitrification. Results indicate that stagnating filters fostered biofilm growth and increased nitrite concentration (2.5 mg/L‐N) above the EPA maximum contaminant level (MCL). Despite FClP being effective at mitigating nitrification and reducing nitrite concentration far below EPA MCL, this was only temporary. Filters that were microbially seeded before an FClP event re‐nitrified immediately after chloramination resumed. Successive FClPs induced a microbial community change and failed at controlling nitrification, resulting in elevated nitrite and microbial exposure.
Estimating the impact of the proposed Lead and Copper Rule Improvements
Samson C.C., Masters S.V., Mathews C.L., Seidel C.J.
Q1
AbstractLead in drinking water can lead to serious health effects, including neurodevelopmental issues and heart disease. In December 2023, the U.S. Environmental Protection Agency (EPA) proposed the Lead and Copper Rule Improvements (LCRI), which lower the Lead and Copper Rule's (LCR's) lead action level (AL) from 15 parts per billion (ppb) to 10 ppb and require both first‐ and fifth‐liter sampling and 90th percentile compliance calculations based on the highest lead levels at sites with lead service lines. A methodology for estimating the likelihood a system will have an AL exceedance (ALE) under the LCRI was developed using Michigan LCR compliance data and applied to national LCR compliance data. Findings were compared to EPA's estimates, indicating EPA may have underestimated the percent of smaller systems (serving 3300) with ALEs and overestimated the percent of larger systems (serving > 10,000), thus underestimating costs and overestimating the benefits of this rulemaking.
Alcohol regeneration of anion exchange resin loaded with per‐ and polyfluoroalkyl substances and organic contaminants
Graham C., Kassar C., Boyer T.H.
Q1
AbstractHydrophobic ionizable organic compounds (HIOCs) like per‐ and polyfluoroalkyl substances (PFAS), pharmaceuticals, and surfactants have been detected in water supplies. Anion exchange is an effective process for the removal of HIOCs from water. Regeneration solution comprising methanol (ca. 75% v/v) and brine is used to effectively desorb HIOCs from resins to overcome the combination of electrostatic and non‐electrostatic interactions. This research investigated different mono‐ and polyhydroxy alcohol cosolvents with brine to regenerate resins saturated with HIOCs to understand the effects of cosolvent properties on regeneration. For PFAS desorption using 25% v/v alcohol in 5% NaCl solution, regeneration efficiency increased in the order methanol < ethanol < 1‐propanol. Experiments with the pharmaceutical diclofenac and surfactant dodecylbenzene sulfonate showed similar regeneration efficiency using 75% v/v methanol in 5% NaCl solution and 25% v/v 1‐propanol in 5% NaCl solution and higher regeneration efficiency using 1‐propanol than ethanol or methanol at the same volume fraction.
Risks of stannous chloride without filtration for hexavalent chromium treatment
Kennedy A., Gregory B., Medina M., Whichard D., Edjan E., Henrie T., Seidel C., Gorman C.
Q1
AbstractWith increasing interest in using stannous chloride without filtration to achieve hexavalent chromium maximum contaminant level compliance in California, there is new urgency to quantify its effects on water quality and risks to public health manifested in distribution and premise plumbing systems. Accordingly, a 12‐week groundwater pilot study was completed using ubiquitous premise plumbing materials under flowing (to waste) and stagnating conditions of hexavalent chromium‐containing groundwater following stannous chloride addition without filtration. Results quantified the accumulation and release of chromium and tin, with total chromium concentrations exceeding regulatory or acceptable levels under stagnating conditions. Sediment with elevated chromium, tin, arsenic, and manganese concentrations was also observed. Given these observations would likely occur and worsen over time in distribution systems that cumulatively serve large populations, the use of stannous chloride without filtration represents an unacceptable risk to public health compared to other, more well‐established, best available technologies.
Plastic water supply connectors: Leaching, hydrocarbon contamination, and decontamination
Isaacson K.P., Le H., Verma A., Youngblood J.P., Shah A.D., Whelton A.J.
Q1
AbstractDisasters can prompt hydrocarbon contaminants to reach building water systems, and ultimately customer fixtures. Here, seven water supply connectors (e.g., ice‐maker lines, faucet connectors, washing machine hoses) were exposed to contaminated water, and were subsequently decontaminated by water flushing. After a 24 h contamination period, water samples were collected after three consecutive 72 h exposure periods. Samples were characterized for volatile organic compound, semi‐volatile organic compound, and total organic carbon concentrations. New, uncontaminated, PVC tubing leached phenol at concentrations that exceeded the health advisory. All materials sorbed more than 90% of hydrocarbon contaminants during the initial exposure period. All materials then released the contaminants into the water during decontamination, at times above health‐based limits. The majority of sorbed mass remained in the plastics at the end of the decontamination effort, indicating the products posed continued leaching risks. Public health guidance considerations and research needs were identified.
Examining how media age affects organic matter removal in activated carbon filtration
Bernstein D.R., Glasgow G.D., Lay M.C., Manley‐Harris M.
Q1
AbstractWater samples from Waiora Drinking Water Treatment Plant in New Zealand were analyzed using excitation‐emission matrix fluorescence spectroscopy (EEMS) and parallel factor (PARAFAC) analysis to evaluate organic matter removal across the plant. The assessment also included the individual granular activated carbon (GAC) filters since the filters had varying media ages due to partial media replacement over a 10‐month period, presenting a unique assessment opportunity. PARAFAC analysis identified humic‐like, tyrosine‐protein‐like, and tryptophan‐protein‐like components representing fluorescent dissolved organic matter groups. The humic‐like component strongly correlated with total organic carbon (TOC) concentration and removal was significantly influenced by filter media age. However, protein‐like components had minimal TOC correlation and were not effectively removed by the overall plant treatment irrespective of filter media age. These findings have implications for disinfection, taste and odor, and bacterial regrowth and require an improved media replacement strategy. Further study of the protein‐like components is required.
Data‐efficient and risk‐based pressure sensor placement optimization for water systems
Chen T.Y., Dryer J., Rathor A., Hoover G., Ganjidoost A.
Q1
AbstractDeployment of remote metering infrastructure can help utilities improve pressure management and limit pipe break impacts. Since it is cost‐infeasible to install sensors to fully cover an entire system, a risk‐based approach where devices are deployed in areas of systemic vulnerabilities will maximize the benefit of these limited resources. Previous work on sensor allocations requires well‐calibrated hydraulic models that contain a full asset inventory. This high barrier of data requirement makes it difficult to apply existing methods. In this research, we present a more efficient methodology with lower data requirements. Proxies for system vulnerabilities are generated using historic break records, and GIS inventories are used to derive candidate installation points. The problem is presented as a generalized version of the well‐studied maximal coverage location problem, where locations are selected for optimal coverage of risky areas. The workflow is demonstrated on a small suburban utility in Pennsylvania, USA.
