Researchers at the University of Kentucky and West Virginia University have been studying problems associated with small rural water systems in the central Appalachian region of the United States for the last decade. After interacting with 145 small utilities, they have identified several problems that are likely similar to other small rural utilities in isolated and mountainous areas across the country. This paper provides both quantitative and qualitative metrics for use in evaluating these problems as well as possible recommendations for addressing such challenges. Among the problems discussed are system (distribution, collection) complexity, economic sustainability, infrastructure stability, workforce development, utility governance, and federal funding inequities and inefficiencies. Recommendations include regionalization, privatization and consolidation of systems, consolidation of services (centralized facility to serve multiple utilities), and various legislative proposals. Additional research is also recommended to identify specific indicators that can be used to identify or predict systems at risk or systems that have become unsustainable so that preemptive actions can be initiated to help prevent a continuing downward spiral toward system collapse or financial insolvency.

Small rural water utilities in the Appalachia region of the US often experience extreme water loss while struggling to maintain water quality compliance. This study quantifies the impact of reducing water loss on distribution system water quality in Martin County, Kentucky. Hydraulic and water quality models were developed, calibrated, and validated using EPANET for chlorine residuals and KYPIPE for trihalomethane (TTHM) formation. The models evaluated water loss reduction scenarios ranging from the current 70% to the industry target of 15%. Results showed that lowering water loss increased residence times, causing chlorine residual declines of 22-68%, with one site falling to the 0.2 mg/L threshold. TTHM concentrations increased by 12-18% in winter-spring and 26-44% in summer-fall, with two sites exceeding the individual 0.080 mg/L maximum contaminant level. These novel findings indicate that reducing water loss can unintentionally degrade water quality, underscoring the need for integrated planning. Recommended mitigation strategies include seasonal operational adjustments, water source and TTHM precursor management, optimized tank management, targeted flushing, and phased infrastructure upgrades. The modeling framework developed offers potential for broader application in other rural systems facing similar challenges.

Water systems in the US are experiencing increasing challenges because of poor governance, unsustainable fiscal policies, an aging workforce, new environmental regulations, and concerns over environmental justice. These challenges will only increase if the specific constraints and barriers to system viability are not first identified and then translated into new policies and best management practices to ensure system sustainability, reliability, resilience, and equity of services. This paper proposes a methodology to accomplish this objective that integrates agent-based models, water distribution models, and sustainability performance models within a larger system dynamics framework.

To increase our understanding of the factors that influence formation of disinfection byproducts (DBPs) in rural drinking systems, we investigated the spatial and seasonal variation in trihalomethane (THM) and haloacetic acid (HAA) concentrations in relation to various chemical and physical variables in a rural public drinking water system in Martin County, Kentucky, USA. We collected drinking water samples from 97 individual homes over the course of one year and analyzed them for temperature, electrical conductivity, pH, free chlorine, total chlorine, THMs (chloroform, bromodichloromethane, dibromochloromethane, dichlorobromomethane, and bromoform) and HAAs (monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, bromoacetic acid, and dibromoacetic acid). Spatial autocorrelation analysis showed only weak overall clustering for HAA concentrations and none for THMs. The relationship between modeled water age and TTHM or HAA5 concentrations varied seasonally. In contrast, there was strong variation for both HAA and THMs, with concentrations of HAA peaking in mid-summer and THMs peaking in early fall. Multiple regression analysis revealed that THM concentrations were strongly correlated with conductivity, while HAA concentrations were more strongly correlated with water temperature. Individual DBP species that only contained chlorine halogen groups were strongly correlated with temperature, while compounds containing bromine were more strongly correlated with conductivity. Further investigation revealed that increased drinking water conductivity associated with low discharge of the Tug Fork River, the source water, is highly correlated with increased concentrations of bromide. Discharge and conductivity of the Tug Fork River changed dramatically through the year contributing to a seasonal peak in bromide concentrations in the late summer and early fall and appeared to be a driver of brominated THM concentrations. Brominated DBPs tend to have higher toxicity than DBPs containing only chlorine, therefore this study provides important insight into the seasonal factors driving risk from exposure to DBPs in rural drinking water systems impacted by bromide.

Fuzzy analysis of water distribution networks (WDNs) determines how the uncertainties in independent or basic parameters (such as nodal demands and pipe roughness coefficients) are propagated to dependent or derived parameters (such as pipe flows, pipe velocities, and available pressure heads). Fuzzy analysis is useful in identifying the vulnerable zone in WDNs. Further, it can be used for the reliability analysis and reliability-based design of WDNs under uncertainty of various parameters. Several methodologies have been suggested for fuzzy analysis. These methodologies are categorized as: (i) optimization-based methodologies and (ii) analysis-based methodologies. The concepts behind these methods along with the brief description of various methods are provided. The membership functions obtained by both optimization- and analysis-based methodologies are compared with two example networks. At the end, methods for obtaining the approximate fuzzy membership functions are discussed.

A nanocomposite membrane incorporating reactive Pd-Fe nanoparticles (NPs) was developed to remediate chlorinated aliphatic hydrocarbons (CAHs) from groundwater. Other than recapturing the produced Fen+ for in -situ regeneration, the functionalized polyanions prevented NPs agglomeration and resulting in a spherical Fe0 core (55 nm, O/Fe = 0.05) and an oxidized shell (4 nm, O/Fe = 1.38). The reactive membranes degraded 92% of target CAHs with a residence time of 1.7 s. After long-term treatment and regeneration, reusability was confirmed through recovered reactivity, recurrence of Fe0 in X-ray photoelectron spectroscopy, and >96% remaining of Fe and Pd. The total cost (adjusted present value for 20 years) was estimated to be 13.9% lower than the granular activated carbon system, following an EPA work breakdown structure-based cost model. However, non-target CAHs from groundwater can compete for active sites, leading to decreased surface-area normalized dechlorination rate (ksa) by 28.2-79.9%. A hybrid nanofiltration (NF)/reactive membrane was proposed to selectively intercept larger competitors, leading to 54% increased dechlorination efficiency and 1.3 to 1.9-fold enlarged ksa. Overall, the practical viability of the developed reactive membranes was demonstrated by the stability, reusability, and cost advantages, while the optional NF strategy could alleviate competitive degradation towards complex water chemistry.

Nanocomposite membranes, with incorporated reactive Pd-Fe nanoparticles (NPs), were developed to remediate chlorinated organics from groundwater. The agglomeration tendency of magnetic NPs was controlled by the constrained membrane matrix and functionalized polyanions. With advanced characterization inside membrane pores, the individual NPs were characterized as the spherical Fe0 core (55 nm, O/Fe = 0.05) and oxidized shell (4 nm, O/Fe = 1.38). For groundwater remediation, 92% of target contaminants were degraded by catalytic membranes at a residence time of 1.7 s. The observed surface-area normalized dechlorination rate (ksa) was, however, 13-59% of that of the intrinsic ksa (derived from the batch dechlorination with individual compounds). This decrease could be attributed to both the mass transfer resistance inside membrane pores (low Reynolds number from 12-63) and the competitive dechlorination. With the integrated nanofiltration membranes, larger competitors were selectively removed, resulting in a 25% increase in dechlorination efficiency and 1.3 to 1.8-fold enlarged ksa. Aside from the long-term stability and reusability, the cost estimation was also conducted to demonstrate the practical implication, where the total cost (the adjusted present value for 20 years) was 13.9% lower than that of the granular activated carbon system.

Kentucky, like other states, faces growing challenges in recruiting and retaining qualified water operators.A recent survey of managers and operators from Kentucky water utilities identified weaknesses in the areas of pay, benefits, training, employee appreciation, COVID, and job satisfaction.The recommendations generated by this survey apply not only to water utilities in Kentucky but possibly to the water industry as a whole.

At the 2013 World Environmental and Water Resources Congress in Cincinnati, Ohio, the ASCE Task Committee on Research Databases for Water Distribution Systems was formed to develop an online open-access repository of water distribution system hydraulic network files for use in applied scientific research. This paper discusses the development of the resulting database, specific model contributions, available model building toolkits, general methods for system classification, and general information related to the database platform and content. It is hoped that the assembled database will promote the advancement of water distribution research into the next decade.

There have been several water main breaks attributed to fire hydrant operations despite the persistent guidance from stakeholders to operate the hydrants “slowly.” Traditional water hammer simulations for determining the safe operational times for every hydrant can be tedious and impractical for most water utilities. While the rapid operation of certain hydrants can generate excessive pressures, most hydrants are benign and do not generate pressures capable of bursting water mains. Using certain simplified water hammer parameters, the authors propose automated methods that can identify benign hydrants at least 100 times faster than the traditional methods where the operation of each hydrant is simulated by manually modifying the baseline models. Detailed analysis with more accurate data can then be performed to determine the precise operational times for the critical hydrants and develop the necessary measures to safeguard their operation.

Challenges associated with water separation technologies for per- and polyfluoroalkyl substances (PFASs) require efficient and sustainable processes supported by a proper understanding of the separation mechanisms. The solute rejections by nanofiltration (NF) at pH values near the membrane isoelectric point were compared to the size- and mass-transfer-dependent modeled rejection rates of these compounds in an ionized state. We find that the low pK a value of perfluorooctanoic acid (PFOA) relates to enhanced solute exclusions by minimizing the presence and partitioning of the protonated organic compound into the membrane domain. The effects of Donnan exclusion are moderate, and co-ion transport also contributes to the PFAS rejection rates. An additional support barrier with thermo-responsive (quantified by water permeance variation) adsorption/desorption properties allows for enhanced separations of PFAS. This was possible by successfully synthesizing an NF layer on top of a poly-N-isopropylacrylamide (PNIPAm) pore-functionalized microfiltration support structure. The support layer adsorbs organics (178 mg PFOA adsorbed/m2 membrane at an equilibrium concentration of 70 mg/L), and the simultaneous exclusion from the NF layer allows separations of PFOA and the smaller sized heptafluorobutyric acid from solutions containing 70 μg/L of these compounds at a high water flux of 100 L/m2-h at 7 bar.

The formation of district metered areas (DMAs) is an efficient strategy for the operation and management of water distribution networks (WDNs). Identifying the most suitable DMA layout is a challenging task for water utilities as it may involve several aspects that need to be addressed simultaneously. This study presents a novel multiphase approach for optimal DMA design that involves: (1) a combination of a fast Newman algorithm (FNA) to identify initial clusters; (2) a nondominated sorting genetic algorithm (NSGA-III) to obtain a set of good DMA configurations while considering several objectives simultaneously; and (3) a multiple attribute decision-making method (MADM) to find the best suited DMA configuration from a set of feasible alternative solutions based on the preference given to each objective. The proposed methodology is applied to two networks including a large benchmark network and a real-life water network. Four problem objectives out of several possible objectives were considered. These are: (1) the total cost of implementation (economic criterion); (2) the pressure deviation (hydraulic criterion); (3) a resilience index (energy criterion); and (4) the total demand shortfall (customer satisfaction criterion). Finally, a multiple attribute decision-making tool [i.e., a simple additive weighing (SAW) method] was used to arrive at a unique solution out of a set of feasible solutions. Results show that the proposed methodology can effectively identify DMAs while considering multiple objectives.

This paper presents an assessment methodology that considers the impact of actual valve locations in a water distribution system in creating discrete isolated groups of pipes or segments when evaluating the performance of the network under a failure condition. The layout of the distribution network used as a case study and the location of the isolation valves are based on a survey of the real system instead of being artificially generated. In addition to evaluating the performance of the system under typical conditions with metrics based on loss of connectivity and the reduction in demand satisfaction, the assessment also includes a consideration for fire flow requirements that has not been widely used in combination with a segment-based reliability assessment. (C) 2021 American Society of Civil Engineers.

An iterative heuristic is proposed to improve the distribution of isolation valves within an existing water distribution network to decrease the magnitude of service interruptions while using the minimum number of valves required to isolate any individual segment within the system. The method takes advantage of graph theory concepts to create a valve augmentation scheme that provides gradual upgrades using the minimum number of new isolation valves at each step. The developed algorithm seeks to provide a tradeoff between an increase in the number of isolation valves and a reduction in water shortages resulting from disconnected pipe segments. The approach is applied to an actual water distribution network with known existing valve locations. The results demonstrate the feasibility and utility of the procedure for multiple operational constraints (i.e., maximum number of valves per segment, or maximum allowable water shortage evaluated over all segments). By use of an incremental performance target set by the user, the algorithm can prove beneficial even for utilities with limited financial resources.

Isolation valves are a fundamental element of water distribution systems because they provide the ability to disconnect sections of the network, which is essential to address routine maintenance and emergency conditions. In order to have a more accurate assessment of the distribution network and consider the role of valves, reliability and resilience assessment methods based on segments (i.e., the smallest set of pipes that can be isolated by the available valves in the distribution network) should be favored. This paper presents a general procedure that uses a standard EPANET network file structure to identify such segments, their elements, and unintended isolations resulting from shutdowns. This procedure is then tested on a set of real water distribution networks.

Well-documented health disparities in Appalachia include high incidence of diabetes, obesity, high blood pressure, and cancer.1–3 The most recent release of America’s Health Rankings places Central Appalachia in particular near the bottom of all U.S. states in health outcomes, with Tennessee 42nd, West Virginia 44th, and Kentucky 45th among the 50 states.4 Similarly, County Health Rankings places six of Virginia’s seven Central Appalachian counties in the state’s bottom quartile for health outcomes.5 Many chronic health conditions disproportionately experienced across the region have been linked to environmental contaminants.6–8 Central Appalachia’s historical economic reliance on mining, agriculture, and other industries has provoked concerns about how environmental exposures may contribute to regional health disparities. Research has found heightened levels of sulfur dioxide and other acidic particles in air samples,9, 10 while community members have voiced water quality concerns in several studies.11–13 Deteriorating infrastructure,14 inappropriate waste disposal,15 and potential occupational exposure risks16 compound the need for at-risk populations to receive clear, timely, and accessible information about potential environmental health threats. Transforming complex scientific evidence into useful, understandable, and readily available resources and tools is essential to helping the people and communities of Appalachia make informed, health-protective decisions about their environment. Environmental health literacy (EHL) is an emerging field that brings together content and methods from health, social, and environmental sciences to promote understanding of how environmental exposures can affect human health.17, 18 Such understanding can spur actions to minimize exposures and improve health outcomes. Local health department staff, healthcare providers, Cooperative Extension agents, librarians, journalists, and others play critical roles in sharing evidence-based information that can help build EHL. Land-grant institutions are well positioned to help Appalachian organizations access and share information to improve regional EHL. The University of Kentucky (UK), for example, houses many initiatives that address regional environmental, health, and socioeconomic challenges. Spearheaded by faculty and staff from the Colleges of Public Health and Engineering, the Department of Dietetics and Human Nutrition, and the Kentucky Water Resources Research Institute, UK teams are conducting three NIH-funded, stakeholder-engaged studies that strive to measure and build regional EHL. Assessing EHL in Appalachia is a pilot study supported by the National Institute of Environmental Health Sciences (NIEHS) through the UK Center for Appalachian Research in the Environmental Sciences (UK-CARES) that addresses the intersection of EHL and water quality. Researchers are leveraging local knowledge from water utility operators and watershed volunteers to identify the knowledge and skills people need to protect their health in the event of water contamination. This study will produce one of the first validated EHL measurement instruments. Protect Your Body from Pollution with a Healthy Lifestyle (Body Balance), a project of the NIEHS-funded UK Superfund Research Program, seeks to increase EHL by educating people about food strategies that may reduce exposures and decrease harmful exposure-related health effects.19 Implemented by Cooperative Extension Service Family and Consumer Sciences (FCS) agents, the seven-lesson curriculum encourages consumption of plant-based foods believed to decrease inflammation and oxidation linked to exposures.20 The curriculum also encourages consumption of lean meats and dairy products as high-fat animal products tend to contain higher concentrations of pollutants.21 Body Balance is available to FCS agents in all 120 Kentucky counties. Integrating Information Resources to Increase EHL in Appalachian Eastern Kentucky, funded by the National Library of Medicine, finds investigators working with Eastern Kentucky residents – including public health and healthcare stakeholders – to assess and improve existing environmental health-related risk maps and other information resources. The study answers calls to bridge knowledge and skills gaps by bringing together scientists, regulatory agencies, and community members to develop and disseminate accessible, understandable, and useful information. At its roots, EHL is context-specific. Communities face diverse health risks from assorted contaminants traveling varied pathways to expose different populations, and these risks must be addressed within unique social, economic, and political contexts. Community residents understand these contexts far better than anyone else. By taking a stakeholder-engaged approach to EHL, the projects described in this article are harnessing local knowledge to help ensure that people in the Appalachian region have the evidence-based, culturally competent guidance that they need to make decisions about both their health and their local environment.

Key Takeaways Modeling water distribution networks involves equations that are difficult to compute by hand, so early systems relied on simplifications and rules of thumb. Early computers were limiting but opened the door to quicker and less expensive calculations; modern computing has allowed more complex simulations. The future of water distribution system modeling may involve cloud-based applications and integration of supervisory control and data acquisition, geographic information systems, and artificial intelligence.

The role of steric hindrance and charge interactions in governing ionic transport through reduced graphene oxide (rGO) and commercial (DOW-Filmtec NF270) membranes was elucidated by a comprehensive study of experimental and established mathematical analysis based on Nernst-Planck equation. A charge-dominated salt exclusion mechanism was observed for the rGO membranes, which exhibited retention from low (7%) to moderate (70%) extent depending on the nature of ions (5 mM). Swelling of GO (1.2 nm interlayer distance) in water beyond the hydrated diameter of ions was attributed as a primary cause for lowering steric hindrance effects. The influence of parameters affecting charge interactions, such as pH and ionic strength, on the extent of salt rejection was modelled. The potential impact of the membrane's charge density, GO loading and interlayer spacing on salt retention was quantified by performing sensitivity analyses. For a high TDS produced water sample, the rGO membranes partially retained divalent cations (Ca:13%) and exhibited high dissolved oil rejection. The membranes were found to be suitable for the treatment of high TDS water with the goal of selectively removing organic impurities, and thus minimizing the impact of osmotic pressure effect. Performance of the membranes was also investigated for retention of water remediation related organic anions, using perfluoro octanoic (PFOA) acid as a model compound. rGO membranes exhibited a charge-dominated exclusion mechanism for retention (90%) of PFOA (1 ppm).

Forum papers are thought-provoking opinion pieces or essays founded in fact, sometimes containing speculation, on a civil engineering topic of general interest and relevance to the readership of the journal. The views expressed in this Forum article do not necessarily reflect the views of ASCE or the Editorial Board of the journal.