bluuebunny/crossref_metadata_2025 huggingface dataset:
Behavioral preference in sequential decision‐making and its association with anxiety
Authors: Zhang Dandan , Gu Ruolei
Published: February 2018

In daily life, people often make consecutive decisions before the ultimate goal is reached (i.e., sequential decision‐making). However, this kind of decision‐making has been largely overlooked in the literature. The current study investigated whether behavioral preference would change during sequential decisions, and the neural processes underlying the potential changes. For this purpose, we revised the classic balloon analogue risk task and recorded the electroencephalograph (EEG) signals associated with each step of decision‐making. Independent component analysis performed on EEG data revealed that four EEG components elicited by periodic feedback in the current step predicted participants’ decisions (gamble vs. no gamble) in the next step. In order of time sequence, these components were: bilateral occipital alpha rhythm, bilateral frontal theta rhythm, middle frontal theta rhythm, and bilateral sensorimotor mu rhythm. According to the information flows between these EEG oscillations, we proposed a brain model that describes the temporal dynamics of sequential decision‐making. Finally, we found that the tendency to gamble (as well as the power intensity of bilateral frontal theta rhythms) was sensitive to the individual level of trait anxiety in certain steps, which may help understand the role of emotion in decision‐making.
Deciphering the roles of FOXO1 in human neoplasms
Authors: Jiang Shuai , Li Tian , Yang Zhi , Hu Wei , Yang Yang
Published: February 2018

Neoplasms constituted an enormous burden and contributed to an estimated 8.2 million deaths in 2012 worldwide. FOXO1 (forkhead box O1), a member of the forkhead box (FOX) family, is a transcriptional factor involved in diverse cellular functions. Herein, we concentrate on recent studies of the antineoplastic roles of FOXO1 in neoplasms. This article may serve as a guide for future research and identify FOXO1 as a potent therapeutic target in neoplasms.
Increased incidence of inguinal hernia in offspring of female survivors of childhood central nervous system tumors
Authors: Ji Jianguang , Sundquist Jan , Sundquist Kristina
Published: February 2018

Female survivors of childhood central nervous system (CNS) tumors experience an increased risk of infertility and various pregnancy complications. We aimed to explore whether the incidence of inguinal hernia could be higher in offspring of female CNS tumor survivors as compared to the general population. Girls who were younger than 15 years of age and diagnosed with CNS tumors between 1958 and 2013 were identified from the Swedish Cancer Registry. By linking with the Swedish Medical Birth Registry, we identified 580 children who were born to mothers of CNS tumor survivors. After 9,662 person‐years of follow‐up, 23 of them were diagnosed with inguinal hernia, giving an incidence rate (IR) of 2.4 per 1,000 person‐years, whereas the IR was 1.2 for the matched controls. Cox regression analysis was used to calculate the hazard ratio (HR) of inguinal hernia. After adjusting for some confounding factors, the incidence of inguinal hernia was significantly increased with an HR of 1.92 (95%CI 1.08–3.41). The association was predominant in offspring whose mothers were diagnosed with CNS tumors at the age of 10 and older, and with CNS tumors located in the brain.
Changes in chlorine and DOX Concentrations in Distribution Systems
Authors: Baribeau Hélène , Prévost Michèle , Desjardins Raymond , Lafrance Pierre
Published: February 2018

The fate of disinfectants and disinfection by‐products (DBPs) has been studied in laboratories under a variety of controlled, constant conditions, but limited information is available about their fate in full‐scale distribution systems. A study of the City of Laval (Québec) distribution system examined changes in the concentrations of chlorine and dissolved organic halogens (DOX) as the water flows through the distribution system. Water was collected in small‐ and large‐diameter pipes with respect to the residence time (RT) of each sampling point. Free and total chlorine concentrations decreased with increasing RT in the distribution system. The influence of pipes on chlorine decay was particularly important in warm water; at similar RTs, chlorine concentrations were lowest in the small‐diameter pipes, greater in the main pipes, and greatest in the batch incubations. The presence of corrosion by‐products in pipes appeared to be the major factor influencing chlorine decay in the distribution system. DOX concentrations generally increased with increasing RT in the presence of free chlorine and decreased when free chlorine concentrations were below the method detection limit. Results point to significant pipe influence on DOX concentrations. DOX decay seemed to be attributable to the chemical instability of some DBPs and the presence of microbial biomass.
Monitoring the Integrity of low‐pressure membranes
Authors: Farahbakhsh Khosrow , Adham Samer S. , Smith Daniel W.
Published: February 2018

The main force driving the burgeoning use of low‐pressure membranes in the drinking water industry has been their ability to remove microbial pathogens to meet stringent water quality regulations. However, the microorganism removal efficacy of low‐pressure membranes may be adversely affected by the lack of membrane integrity. Over the past two decades, membrane manufacturers have developed various direct and indirect tests for monitoring the integrity of low‐pressure membranes. Many states currently require such tests to be conducted on a regular basis. The most widely used practice in the membrane water treatment industry is the use of the pressure hold (i.e., pressure decay) test for detecting minor breaches of membrane integrity; particle counting and/or turbidity monitoring are used to meet regulatory requirements and to detect more pronounced breaches in membrane integrity. This article summarizes the current state of knowledge about integrity monitoring methods for membrane filtration systems.
Land Conservation and Watershed Management for Source Protection
Authors: Barten Paul K. , Ernst Caryn E.
Published: February 2018

The constantly expanding diversity of contaminants from changing land use, coupled with greater pollutant loads and fewer natural barriers, has made treatment more challenging and expensive and increased the chances that contaminants will reach our taps. The 1996 amendments to the Safe Drinking Water Act required that states conduct a Source Water Assessment for every public water supply in the country, reflecting a renewed national focus on source water protection as a tool to prevent the contamination of drinking water supplies. Although some resources were provided to the states to conduct assessments, no resources have been appropriated for protection strategy implementation, neither have any mandates that they occur been issued. Tools and resources are needed to inform and motivate local and regional protection efforts. This article describes a successful process that demonstrates how locally driven source water protection efforts that leverage local, state, and federal resources can lead to successful implementation of protection strategies. This study highlights how water supply managers can work with elected officials, landuse planners, watershed associations, and others in their source area to conduct geographic information systems analyses, identify threats to supplies from land use, and develop joint efforts to address those threats through a variety of funding sources.
Technical Note: Electrochemical Generation of Perchlorate in Municipal Drinking Water Systems
Authors: Jackson Andrew , Arunagiri Sangeetha , Tock Richard , Anderson Todd , Rainwater Ken
Published: February 2018

This article documents the first known in situ electrochemical production of perchlorate within a public water distribution system. In this detailed incident, perchlorate (ClO4−) was detected in the distribution system of Levelland, Texas, and was eventually isolated to one elevated storage tank. Theoretical considerations supported the production of ClO4− by an electrochemical process within the tank. ClO4− was produced (64–113 μg/L in 338 h) in laboratory experiments that simulated the cathodic protection system in place in the storage tank. Because cathodic protection systems are widely used, this research confirms a potentially troubling mechanism of ClO4− generation.
CFD Design Approach for Chlorine Disinfection Processes
Authors: Greene Dennis J. , Farouk Bakhtier , Haas Charles N.
Published: February 2018

Current approaches for chlorine disinfection process design involve application of a C x T (concentration x time) concept or the integrated disinfection design framework (IDDF) (Bellamy et al, 1998). This study presents a new design approach for chlorine disinfection that uses computational fluid dynamics (CFD). CFD models were developed to predict flow structure, mass transport, chlorine decay, and microbial inactivation in a continuous‐flow reactor and associated piping. Past CFD models for chlorine disinfection have only predicted chlorine contactor flow structure and residence time distribution (Crozes et al, 1999; Wang & Falconer, 1998; Hannoun & Boulos, 1997; Stambolieva et al, 1993). The model described here incorporates experimentally derived terms for chlorine decay (free and combined) and microbial inactivation (Escherichia coli, MS2 bacteriophage, and Giardia muris) based on the work of Haas et al (1995). CFD predictions were in good agreement with the experimental data set over a wide range of microbial inactivation rates.
Detection of Infectious Cryptosporidium in Filtered Drinking Water
Authors: Aboytes Ramon , Di Giovanni George D. , Abrams Felicia A. , Rheinecker Corey , McElroy Wyndi , Shaw Nancy , Lechevallier Mark W.
Published: February 2018

Monitoring of 82 surface water treatment plants revealed that 1.4% of 1,690 100‐L finished water samples tested positive for infectious Cryptosporidium using the cell culture‐polymerase chain reaction). Infectious oocysts were detected in finished water samples from 22 water treatment plants (26.8%). Genotype analysis identified 23 isolates as Cryptosporidium parvum and one isolate as Cryptosporidium hominis. All isolates subgenotyped were shown to be genetically distinct environmental isolates. Analysis of the water quality and treatment plant characteristics showed no differences between the positive and negative sites. More than 70% of the positive samples occurred in filtered water samples of <0.1 ntu, and 20% of the positive samples were in water of <0.05 ntu. There was no association among Cryptosporidium occurrence and source water type, microbial indicators, or plant operation and treatment. It was concluded that given sufficient testing, nearly all conventional treatment plants would be at risk for passing infectious oocysts. Based on this study, the overall risk of Cryptosporidium infection for conventionally treated drinking water was 52 infections/10,000 people/year, with an 80% credible range of 9–119 infections/10,000 people/year. It was also concluded based on these studies that conventional treatment requires an additional treatment barrier, such as ultraviolet light disinfection, to meet the US Environmental Protection Agency risk goals.
Reducing Urban Runoff With Smart ET Controllers: Report Review
Authors: Berg Joe , Diamond Richard
Published: February 2018

This article discusses a new report called the Residential Runoff Reduction Study that gives substantial support to the claim that landscape overwatering and urban runoff can be controlled with a new technology called the evapotranspiration (ET) controller. The four primary purposes of the study were: to expand earlier studies of evapotranspiration (ET) pager‐signal controller technology that have been used to manage irrigation water for residential homes and larger dedicated landscape areas; to evaluate the effectiveness of an education program for customers to enlist their aid in reducing runoff; to determine the connection between proper landscape water application and the quantity and quality of dry weather runoff into storm drain systems; and, to gauge acceptance of the water management technology (ET controllers) and the visual appearance of participant landscapes. The study area included five neighborhoods in Irvine, California. Data was gathered from the 18‐month study and evaluated for water efficiency and savings, dry season runoff changes, and changes in the quality of the dry season runoff water.
Can succession planning impact your utility's performance?
Authors: Fahnestock Christine M. , Brethower Karen Searles
Published: February 2018

This article discusses how succession‐planning can ensure continuity of leadership at water utilities in the upcoming years when an exodus of institutional knowledge and leadership is expected to occur as members of the Baby‐Boom generation retire. Progressive utilities are using succession planning as a best practice to prepare for the transition risk that accompanies a CEO or senior officer departure. A domino effect occurs when any senior officer leaves, and at such times succession planning is used to assess the cadre of top leadership talent. A set of moves based on these assessments yields a stronger team and greater bench strength, as opposed to weakening the net effectiveness of the senior team. The article discusses two best‐practice examples of how utility CEOs and their boards of directors faced succession planning challenges.
Scenario Planning: A Tool to Manage Future Water Utility Uncertainty
Authors: Means Ed , Patrick Roger , Ospina Lorena , West Nicole
Published: February 2018

This article, the fourth in a six‐part series, takes a timely look at scenario planning. This powerful tool can be used by strategic planners to frame the future and is useful in guiding representatives of the public water supply community when planning for future uncertainty. This article presents five scenarios that were discussed at a 2002 AWWA Research Foundation workshop in which participants evaluated societal, business, and utility trends and used scenario planning to craft a water utility strategy for future success. A complete scenario regarding global warming is presented in the article, along with four condensed scenarios dealing with how utilities will assimilate developing technology, the effects of changes in the population on demands exerted on utilities, the development of creative partnering and regionalization, and water utility response to catastrophic events.
Have utilities switched to chloramines?
Authors: Seidel Chad J. , McGuire Michael J. , Summers R. Scott , Via Steve
Published: February 2018

Secondary disinfection practices of water utilities, particularly the use of chloramines, are at the center of several national drinking water policy discussions. As a response to this ongoing dialogue, AWWA commissioned the Secondary Disinfection Practices Survey – a web‐based survey of water utilities – to determine the percentage of utilities currently using chloramines and those intending to convert to the use of chloramines in the future. Results of the survey indicate 68% of utilities currently use chlorine for secondary disinfection, 29% use chloramines, and 3% use no secondary disinfectant. The results of this survey serve to inform national drinking water policy discussions (i.e., the Stage 2 Disinfectants/Disinfection Byproducts Rule) and to support the continued increase in the use of chloramines.
Effect of bacterial sulfate reduction on iron‐corrosion scales
Authors: Lytle Darren A. , Gerke Tammie L. , Maynard D J. Barry
Published: February 2018

Iron–sulfur geochemistry is important in many natural and engineered environments, including drinking water systems. In the anaerobic environment beneath scales of corroding iron drinking water distribution system pipes, sulfate‐reducing bacteria (SRB) produce sulfide from naturally occurring sulfate in the bulk water. This sulfide subsequently can affect iron geochemistry of the scale and the protective qualities of the scale. The authors studied the effect of bacterial sulfate reduction on the nature of iron corrosion scales collected from two drinking water distribution systems—one using surface water and the other groundwater but both with relatively high sulfate concentrations. Reduced sulfur proved to be a significant component of all iron scales studied, reaching up to 22% (wt%) in the scale from the groundwater system and 2% in the surface water system. X‐ray diffraction showed the presence of elemental sulfur (S0) and marcasite (FeS2). Sulfur extractions showed major S0 and FeS2 in all scales but only minor amounts of iron(II) sulfide (FeS) and sulfate ion (SO42−). Sulfur isotope measurements showed δ34S in the scales to be 20–40 permil (parts per thousand) lighter than in the source SO42−, confirming the important role of SRB in forming the reduced sulfur. Other important iron minerals found were goethite (α‐FeOOH) and lepidocrocite (γ‐FeOOH). Magnetite (Fe3O4), which is believed to be an important mineral in protecting iron pipes from extensive corrosion and iron release, was present in iron scales collected from the surface water system but not in those from the groundwater system.
Evaluation of water mixing characteristics in distribution system storage tanks
Authors: Mahmood Ferdous , Pimblett James G. , Grace Nigel O. , Grayman Walter M.
Published: February 2018

Distribution system storage tanks that are underutilized or have poor mixing characteristics are one of the challenges faced by many water utilities in maintaining water quality in their distribution systems. Computational fluid dynamics modeling, water temperature measurements, and chlorine residual measurements can be effective tools in predicting mixing characteristics inside storage tanks. This article demonstrates how these tools can be used to determine mixing characteristics within storage tanks, identify tanks with poor mixing characteristics (and thus the greatest potential for water quality deterioration), and help modify designs to improve mixing characteristics. Field data are presented to demonstrate how design modifications improved water mixing characteristics in an operating storage tank.
Hydraulic Transient Guidelines for Protecting Water Distribution Systems
Authors: Boulos Paul F. , Karney Bryan W. , Wood Don J. , Lingireddy Srinivasa
Published: February 2018

Transients can introduce large pressure forces and rapid fluid accelerations into a water distribution system. These disturbances may result in pump and device failures, system fatigue or pipe ruptures, and even the backflow/intrusion of dirty water. Many transient events can lead to water column separation, which can result in catastrophic pipeline failures. Thus, transient events cause health risks and can lead to increased leakage or decreased reliability. Transient flow simulation has become an essential requirement for ensuring safety and the safe operation of drinking water distribution systems. This article provides a basic understanding of the physical phenomena and context of transient conditions, presents practical guidelines for their suppression and control, and compares the formulation and computational performance of widely used hydraulic transient simulation schemes. Such capabilities greatly enhance the ability of water utilities to conceive and evaluate cost‐effective and reliable water supply protection and management strategies and safeguard public health.
Asset Management Planning AND REPORTING OPTIONS FOR WATER UTILITIES
Authors: Tichich Mike Ma , Allen Jason , Allen Robert
Published: February 2018

Industry studies in recent years have raised awareness of the magnitude of asset renewal and replacement needs in the water industry, but little comparative work has been done on asset management. To help fill this gap, the Awwa Research Foundation sponsored the study summarized in this article. The full study forms a “casebook” of comparative asset management options. Eleven utilities of diverse sizes, asset ages, availability of automated information, and engagement in asset management worked with the project team to test and evaluate three levels of asset management planning: basic, high‐end, and strategic. The study results showed that even a basic asset management option has considerable value for a water utility. More advanced and strategic options require significant additional investment, but 80% of the utilities that participated in this project found the benefits to outweigh the costs and plan to implement programs that emulate these options.
Smart Water Application Technology: A Water Utility/Irrigation Industry Partnership
Authors: Hoyenga Jill , Reaves Robert
Published: February 2018

The demand management potential of efficient irrigation technology is enormous, and utility managers are realizing that forming partnerships with the landscaping and irrigation industries can help manage water distribution systems with mutual benefits. This article outlines the development of protocols for testing the efficiency of new irrigation technologies under a volunteer initiative called “Smart Water Application Technology.” Sponsored by the Irrigation Association, the initiative has resulted in an accurate, science‐based performance assessment process for “smart” controllers, as well as a robust educational campaign. The purpose of this paper is to help educate water utility professionals about the management potential of efficient irrigation technology and highlight the importance of conducting efficiency testing on new technologies. The secondary purpose is to encourage partnerships between water utilities and the irrigation industry in water resource management.
An evaluation of the relationship between SUVA and NOM coagulation using the ICR database
Authors: Archer Aaron D. , Singer Philip C.
Published: February 2018

The Objective of this research was to examine relationships between specific ultraviolet absorbance (SUVA) and the amenability of water to coagulation for the removal of natural organic matter (NOM) to demonstrate that the removal of total organic carbon, UV‐absorbing organics, and disinfection by‐product precursors is a function of the raw water SUVA value. Theory and previous studies suggest that SUVA (defined as UV254 normalized with respect to dissolved organic carbon) is a useful indicator of the characteristics of dissolved organic matter in relation to its susceptibility to coagulation and its reactivity with chlorine. Data collected and assimilated under the Information Collection Rule, the largest nationwide water quality survey ever conducted, were analyzed to investigate the association between raw water SUVA and the enhanced coagulation matrix as outlined in the Stage 1 Disinfectants/Disinfection Byproducts Rule. Findings demonstrated the ability of SUVA to predict the reactivity of NOM and provide the basis for an alternative enhanced coagulation matrix.
Third‐party billing of multifamily customers presents new challenges to water providers
Authors: Mayer Peter W. , Bennett Dick , Deoreo William B. , Towler Erin
Published: February 2018

Third‐party billing for water and wastewater in the multifamily housing sector is growing at an estimated rate of 25% per year, but many water providers are unaware of the effect, implications, administrative issues, and potential water savings of this practice. The National Multiple Family Submetering and Allocation Billing Program Study evaluated the merits of separate billing programs including the potential water savings, costs, and benefits from the perspectives of utilities, property owners, and residents and analyzed the accompanying administrative and regulatory issues. Properties equipped with submeters or that have undergone a billing system conversion were identified and compared against control properties in which water and wastewater fees are included as part of the rent. It was found that the practice of installing individual water meters (submetering) in multifamily properties and billing based on actual consumption results in substantial water savings. Water billing practices based on allocation methods (ratio utility billing systems) did not effect savings in water consumption.
DBPs in drinking water: Additional scientific and policy considerations for public health protection
Authors: Singer Philip C.
Published: February 2018

Disinfection byproducts (DBPs) have been regulated in finished drinking water for more than 25 years. This article, adapted from the Clarke Prize Lecture delivered by the author, analyzes several aspects related to the science and policy of DBP regulation and control and highlights deficiencies that are undermining public health protection. These deficiencies include limitations in the epidemiological studies that were conducted on the adverse health effects of DBPs and led to their regulation as well as shortcomings in the regulatory approach that the US Environmental Protection Agency has adhered to over the past quarter‐century. In addition, water suppliers have been relatively shortsighted in their methods of controlling DBP formation and must look to long‐term management and treatment methods. Drawing on his 31 years of research on the subject, the author has developed concrete suggestions for improving DBP health effects studies, regulatory approaches, and control strategies.
The need for comprehensive transient analysis of distribution systems
Authors: Jung Bong Seog , Karney Bryan W. , Boulos Paul F. , Wood Don J.
Published: February 2018

Many surge analysis and design rules have evolved over time to help utilities cope with the complexity of transient phenomena. These rules have been widely applied to simplify analysis by restricting both the number and difficulty of the transient cases that need to be evaluated. On further reflection, however, the implicit assumption that elementary and conservative rules are a valid basis for design has often been shown to be questionable and sometimes dangerous. Indeed, many published guidelines are so misleading and so frequently false that they should only be used with extreme caution, if at all. This article specifically reviews a number of guidelines or suggestions found in various AWWA publications for water hammer analysis and provides a set of warnings about the misunderstandings and dangers that can arise from such simplifications. The authors conclude that only systematic and informed water hammer analysis can be expected to resolve complex transient characterizations and adequately protect distribution systems from the vagaries and challenges of rapid transients.
Aquatic Ecosystem Protection and Drinking Water Utilities
Authors: Postel Sandra L.
Published: February 2018

Aquatic ecosystems provide irreplaceable benefits, including water supplies, food for people and wildlife, water purification and filtration of pollutants, flood and drought mitigation, even recreational opportunities. As the economic and ecologic services provided by aquatic ecosystems gain more recognition and the deleterious effects of mismanaging water resources become more apparent, the global water community is taking steps toward ecologically sustainable water management. Because their operations have significant and far‐reaching consequences for aquatic ecosystems, drinking water providers can play a major role in safeguarding the health of these systems. Strategies to protect aquatic ecosystems include reducing water demand through conservation, managing water within the bounds of an ecological flow prescription, planning for ecosystem allocation during drought, and protecting source watersheds. With urban populations growing and water demands on the rise, utilities must act now to ensure that the benefits provided by healthy aquatic ecosystems are available to future generations.
Using spore removal to monitor plant performance for Cryptosporidium removal
Authors: Brown Richard A. , Cornwell David A.
Published: February 2018

Data from available literature indicate that Cryptosporidium oocysts are removed more efficiently than aerobic spore‐forming bacteria during water treatment processes involving clarification and filtration. Therefore, monitoring removal of naturally occurring aerobic spores can provide a conservative estimate of the potential for Cryptosporidium removal in full‐scale water treatment processes, which in turn can be used to establish the demonstration of performance credit allowed by the Long Term 2 Enhanced Surface Water Treatment Rule as well as to provide a valuable performance evaluation tool for water plant operators. The results from this study showed that (1) median raw water spore concentrations ranged from 300 to 3,000 spores/L for two lake sources and 80,000 to 400,000 spores/L for four river sources; (2) median filtered water spore concentrations rarely exceeded 5 spores/L, and these levels of removal were not apparently dependent on source water concentration; and (3) >4‐log spore removal could not be mathematically demonstrated unless raw water levels exceeded 10,000 spores/L (e.g., river sources).
Internal and external sources of THM precursors in a midwestern reservoir
Authors: Bukaveckas Paul A. , McGaha Dale , Shostell Joseph M. , Schultz Richard , Jack Jeffrey D.
Published: February 2018

Trihalomethanes (THMs) are contaminants of drinking water produced by the reaction between chlorine and natural organic matter. Determination of THM formation potential (THMFP) is a means of quantifying precursor abundance in waters from diverse sources. THMFP in river water entering and leaving Taylorsville Lake (Ky.) was measured to assess internal and external sources of THM precursors. THMFP in Taylorsville Lake was largely determined by watershed inputs. External inputs from tributary streams accounted for 80% of reservoir THMFP, and internal processes resulted in a net generation of 20%. Chlorophyll concentrations in the main tributary (Salt River) were comparable to those measured in Taylorsville Lake, suggesting that algal production in source waters may be important in regulating precursor supply to the reservoir. The highest THMFP was found in hypolimnetic samples, and peak export from the reservoir occurred during fall turnover, suggesting that decomposition of sedimenting organic matter both delayed and enhanced precursor release.
Legionella reduction after conversion to monochloramine for residual disinfection
Authors: Weintraub June M. , Flannery Brendan , Vugia Duc J. , Gelling Lisa B. , Salerno James J. , Conroy Michael J. , Stevens Valerie A. , Rose Charles E. , Besser Richard E. , Fields Barry S. , Moore Matthew R.
Published: February 2018

Previous studies have shown that monochloramine disinfection of municipal water supplies is associated with decreased risk of healthcare‐associated Legionnaires— disease. A twoyear, prospective environmental study was conducted to determine whether converting from chlorine to monochloramine for water disinfection would decrease Legionella colonization of hot water systems. Water and biofilm samples were collected from 53 buildings. Prevalence ratios comparing Legionella colonization before and after monochloramine disinfection were adjusted for water system characteristics. Legionella colonized 60% of the hot water systems before monochloramine conversion versus 4% after conversion. The median number of colonized sites per building declined significantly with monochloramine disinfection. Increased prevalence of Legionella colonization was associated with water heater temperatures below 50oC, buildings taller than 10 stories, and interruptions in water service. Although no outbreaks of Legionnaires— disease were found, the study provides support that use of monochloramine in water supplies may reduce Legionella transmission and incidence of Legionnaires— disease.
Using aggregation/skeletonization network models for water quality simulations in epidemiologic studies
Authors: Perelman Lina , Maslia Morris L. , Ostfeld Avi , Sautner Jason B.
Published: February 2018

In recent years, epidemiologic studies and vulnerability assessments have come to rely on water distribution system models for refined estimates of street‐level exposure scenarios in conducting health studies and assessing potential contamination occurrences. A water distribution system network analysis at the street level can result in thousands to tens of thousands of hydraulic appurtenances such as pipelines, hydrants, and valves, making model calibration, verification, and system operation simulations time‐consuming and complex. Methods of aggregation, skeletonization, and network simplification have been used to reduce the complexity of the networks being analyzed. The issue then is whether network aggregation based on hydraulic characteristics and controls conserves mass so that the simplified network provides reliable results for the water quality analyses needed for epidemiologic studies and contamination assessment. In this study, a network aggregation methodology based on both hydraulic and water quality aggregation of an all‐pipes network was applied to a complex allpipes network described in the literature and used for an epidemiologic study. Simulation results obtained using the quality aggregation method, closely resembled both hydraulic (i.e., pressures) and water quality (i.e., concentrations) behavior of the original full‐sized (all‐pipes) system, while reducing system size by almost half.
Pilot Study of Radionuclide Removal: Using Conventional Iron‐ and Manganese‐removal Equipment
Authors: Vesterbacka Pia , Salonen Laina
Published: February 2018

This article discusses a pilot study that examined the feasibility of using Fe‐ and Mn‐removal equipment to remove natural radionuclides from drinking water. The goal was also to identify removal techniques that should be studied further, and to specify whether any technical changes should be made to improve removal efficiencies. The study concluded that, although removals of various nuclides are not always complete, removal may be sufficient to meet regulatory requirements. Using aeration and filtration equipment, 222Rn removal was often insufficient because of high 222Rn concentrations, and because an insufficient amount of air was applied with the removal equipment. Removal of 226Ra using manganese greensand filtration and a cation exchanger was efficient, and 238U removal was efficient using an anion exchanger.
A Regulator's Perspective on Workforce Issues: Water and Wastewater Operators
Authors: Boepple‐Swider Teresa M.
Published: February 2018

As large numbers of water and wastewater utility employees retire or leave to seek opportunities elsewhere, utilities are left to fill these positions and ensure that the employees’ knowledge is not lost forever. Journal AWWA Editor Marcia Lacey conducted an e‐mail interview with Teresa M. Boepple‐Swider, Professional Certification Section Chief for the New York State Department of Health, to gain perspective on how today's workforce issues affect plant operators.
Effective Crisis Communication During Water Security Emergencies
Authors: Minamyer Scott
Published: February 2018

This article discusses effective crisis communication as a key responsibility of water utility officials and public information officers during emergencies. Mental noise theory, a primary construct of risk communication, is discussed in the article and indicates that when people are extremely upset, they often have difficulty hearing, understanding, and remembering information. The challenge for risk communicators is developing a limited number of key messages that are brief, credible, and easily understood. The article presents a powerful tool available to water sector crisis communicators for identifying and developing key messages called message mapping. The article discusses several principles that come into play when developing messages for high‐stress situations. A sidebar is included in the article presenting the three key points of message mapping.
Charting the course ahead
Authors: Runge Jon , Mann John
Published: February 2018

The State of the Industry (SOTI) Report 2008, the fifth installment of AWWA's annual study of issues confronting the water industry, provides valuable insight into the trends and factors influencing water industry challenges and creates a framework for setting priorities and strategies to address these issues. Professionals from all segments of the water community shared their individual experiences as well as some suggestions for tackling the challenges ahead. According to the 2008 survey respondents, the top concerns are source water supply, infrastructure, regulatory issues, workforce needs, and business factors. This year's survey results indicate that perception of the overall soundness of the industry has continued its negative trend; U.S. respondents were even less optimistic about the state of the industry five years down the road. For industry leadership, the 2008 SOTI data constitute a call to action for increased vigilance in the issue areas deemed most essential and inadequately addressed and the development of innovative strategies to resolve these concerns.
A review of biofilms in domestic plumbing
Authors: Eboigbodin Kevin E. , Seth Allyson , Biggs Catherine A.
Published: February 2018

Several factors have been shown to favor biofilm formation in water distribution systems, including the capability of bacteria to resist disinfectants, improper use of disinfectants, the nature and concentration of biodegradable substances, temperature, and plumbing materials. To date, most research relating to drinking water biofilms has focused on the materials that make up the distribution system before water enters the consumers— plumbing systems. However, drinking water should also meet the necessary quality requirements at the point of consumption even though domestic plumbing systems are usually not constructed from the same materials that are used to construct distribution systems. This article provides a review of the current literature related to the analysis of biofilms found or produced in domestic plumbing systems and highlights the microorganisms identified as well as causes and strategies for control.
Building a Business Case for WARN Participation
Authors: Blankenship Linda , Morley Kevin M.
Published: February 2018

This article discusses the Water/Wastewater Agency Response Network (WARN) program that encourages utilities to help one another in response and recovery efforts. The concept grew out of a series of wildfires and earthquakes in California in the early 1990s that affected a number of water systems. Further information on WARN's development is provided, along with the WARN concept of intrastate networks offering utilities added security by being there to help each other when emergencies arise. An AWWA‐initiated study and report on the economic benefits to utilities of participating in a WARN is discussed. The report is titled, “Economic Benefits of Participating in a Water/Wastewater Agency Response Network (WARN),” and provides a general reference for business case analysis of participating in a WARN, and guidance for utility managers on the strategy, potential benefits and outcomes, costs, and resource implications for WARN members responding to various types of incidents. The article discusses the significance of the comprehensive survey that was the core of the study, along with the benefits of WARN participation both tangible and intangible, and costs associated with WARN participation. The AWWA report presents three utility case studies that demonstrate the efficacy of WARN membership.
Occurrence of perchlorate in sodium hypochlorite
Authors: Greiner Peter , McLellan Clif , Bennett Dale , Ewing Angie
Published: February 2018

Perchlorate is a contaminant of health concern because exposure to high levels over extended periods may adversely affect thyroid activity. In response to recent findings of perchlorate in sodium hypochlorite, NSF International surveyed sodium hypochlorite products used to treat drinking water to better understand the occurrence of perchlorate as a contaminant. Perchlorate contamination was found to occur in more than 90% of sodium hypochlorite samples from production facilities across North America. Results also indicated a trend of increasing perchlorate concentration as the hypochlorite aged. The duration and conditions of storage can affect the levels of the contaminant in a utility's hypochlorite supplies and ultimately its drinking water. The investigation provided a basis for recommendations to minimize perchlorate formation and lower the potential for its unintended addition to drinking water. Sodium hypochlorite should be stored in the dark at cool temperatures, diluted if possible, and used within a few weeks of manufacture.
The Groundwater Replenishment System
Authors: Markus Michael R.
Published: February 2018

This article provides an overview of the Groundwater Replenishment (GWR) System, operated by the Orange County Water District in southern California. It is the world's largest water purification and reuse project of its kind. The GWR system benefits are presented, along with its various components, the use of grant money to reduce the total project cost, specific quality requirements of the project, brief summary of operational experiences, and the visionary partnership resulted in advancing water reuse.
Permeation of organic contaminants through PVC pipes
Authors: Mao Feng , Gaunt James A. , Ong Say Kee
Published: February 2018

Permeation of benzene, toluene, and trichloroethylene (TCE) through polyvinyl chloride (PVC) pipes from vapor and aqueous phases was investigated using pipe‐bottle tests, gravimetric sorption tests, and microscopic visualization tests. Vapors of the three compounds at saturated vapor pressures were found to permeate 1‐in. PVC pipes within 30 days; saturated aqueous solutions of benzene and TCE also permeated 1‐in. PVC pipes but at breakthrough times ranging from 60 to 240 days, depending on mixing conditions. For PVC pipes exposed to organic vapors that were in equilibrium with ∤ 40% v/v benzene or toluene in National Institute of Standards and Technology reference fuel and to water containing ∤ 60% of the aqueous solubility of benzene and toluene, insignificant sorption and no moving front were detected. Test results suggest that PVC pipe materials are an effective barrier against the permeation of benzene, toluene, ethylbenzene, and xylenes in either gasoline vapors or gasoline‐contaminated groundwater at typical contaminated sites.
The Forest—Drinking Water Connection: Making Woodlands Work for People and for Nature
Authors:   The Nature Conservancy, Jenkins Dylan , Repasch Stephen
Published: February 2018

This article discusses The Nature Conservancy's Working Woodlands program, which offers attractive benefits to forestland owners in Pennsylvania and other eastern states, including forestland protection, forest management certification, and financial dividends from the sale of forest carbon offsets. The program is designed to keep woodlots functioning at their highest level for habitat and watershed protection and also for recreational uses, sustainably harvested timber, and a new source of income from selling forest carbon. The article discusses program benefits, costs, forest certification, carbon trading, and program eligibility.
Nutrients and metals effects on nitrification in drinking water systems
Authors: Zhang Yan , Edwards Marc
Published: February 2018

The activity of nitrifying bacteria in potable water systems was strongly affected by nutrient levels and the presence of certain metals. Specifically, copper (Cu) and zinc (Zn) levels > 100 μg/L and phosphate levels < 5 μg/L inhibited nitrifier activity. This research also showed that inorganic carbon has important direct and indirect effects on nitrification because inorganic carbon (0.1 mg C/mg oxidized nitrogen) was required for autotrophic nitrifier growth, but higher inorganic carbon reduced the toxicity of Cu/Zn and can increase phosphate availability to nitrifying bacteria. Different pipe materials modify nutrient availability to nitrifiers and thus either inhibit or enhance nitrifier activity. For example, orthophosphate can leach to water during corrosion of some metallic alloys but can be removed from water during corrosion of other materials.
Integration of water and wastewater utilities
Authors: Katko Tapio S. , Kurki Vuokko O. , Juuti Petri S. , Rajala Riikka P. , Seppala Osmo T.
Published: February 2018

The concepts and principles associated with Integrated Water Resources Management (IWRM) have been around for many decades. The IWRM approach of merging water and wastewater utilities into a single organization has several advantages, particularly for larger urban areas. Not only can pipes for both services be laid in the same excavation, but human resources can also be conserved through cross‐training of water supply and wastewater services personnel. Although there are advantages, for a variety of reasons the concept has been slow to gain acceptance. Some of these reasons have to do with the approach to utility services in different countries; for example, in Germany wastewater services fall under the purview of the roads department. Utility services in Finland, and to a lesser extent Sweden, provide opportunities to study the implementation of IWRM on a wider scale. Certainly the mergers of water and wastewater utilities in these two countries have had their challenges. There has sometimes been little cooperation, and even a culture of rivalry between staff of the merged utilities. But more significant, there has been very little documentation about how the processes of separate utilities providing different services were actually merged. This article looks at what is known and what information is lacking about these types of mergers and suggests areas for additional study. The authors suggest that the lessons learned from the implementation of IWRM in Finland and Sweden have wider global applications as countries search for ways to incorporate greater efficiencies while working with increasingly limited resources.
Using 3D LIF to investigate and improve performance of a multichamber ozone contactor
Authors: Kim Dooil , Elovitz Michael , Roberts Philip J.W. , Kim Jae‐Hong
Published: February 2018

Three‐dimensional laser‐induced fluorescence (3D LIF) was applied to visualize and quantitatively analyze hydrodynamics and mixing in a multichamber ozone contactor, the most widely used design for water disinfection. Results suggested that mixing was characterized by extensive short‐circuiting between chambers, internal recirculation within the chambers, and dead zones at the chamber centers. Because of these nonideal mixing behaviors, the hydrodynamics in the entire reactor showed greater dispersion than a series of completely mixed reactors. These flow patterns could be diminished by decreasing the channel width, whereas the effects of the flow rate and baffle gap were negligible within the range investigated. Accordingly, reactive transport model simulations suggested that overall reactor performance could be significantly improved by preventing these flow behaviors. The 3D LIF technique developed and presented in this study is expected to provide a novel tool for reactor diagnosis, retrofitting to improve performance, and new reactor design.
Members Seeking Excellence—That's AWWA's Niche
Authors: Lafrance David
Published: February 2018

Last June AWWA's Board of Directors adopted a new strategic plan. Our vision has evolved to be “A better world through better water.” That is a powerful vision ‐ one that ties the importance of water to the quality of life around the world. Also, this is a member‐focused vision ‐ not an organization‐focused vision. Because AWWA is a membership organization it is important that our vision align with and reflect the ultimate goal of the work that AWWA's members do every day ‐ making the world better by making water better. LaFrance thanks our members for being “dedicated to the world's most important resource” ‐ which, by the way, just happens to be AWWA's new organizational tagline.