bluuebunny/crossref_metadata_2025 huggingface dataset:
Committee Report: Applying worldwide BMPs in water loss control
Authors:   Awwa Water Loss Control Committee
Published: February 2018

Despite growing pressures on water suppliers from drought, water shortages, and other challenges, the North American water industry has been slow to implement reliable and consistent water supply auditing and loss control. AWWA's Technical and Educational Council funded a survey that confirmed that US water loss reporting practices are limited and vary widely. In 2000, an International Water Association task force, with AWWA participation, assembled a water audit methodology as a best management practice (BMP) that is applicable to water suppliers worldwide, providing a framework to tabulate supplier water use and loss. Additionally, effective leakage management methods have been advanced with great success. This article advocates the use of the international water audit method and water and revenue loss control technologies that offer North American water utilities an outstanding water resource recovery opportunity and a great stride toward sustainability.
Well clogging by particles in Dutch well fields
Authors: Timmer Harrie , Verdel Jan‐Dik , Jongmans Antoine G.
Published: February 2018

For the water supply company Hydron South Holland in the Netherlands, clogged wells constituted a significant problem that lowered production capacity of the well field, disrupted the purification process at the treatment plant, and decreased overall revenues. This study was undertaken to develop a better understanding of the clogging process, the nature of the clogging materials, and the exact position of these materials in the well. The Hydron South Holland wells pump anaerobic groundwater from aquifers consisting of Pleistocene, sandy, and fluvial sediments. Samples were collected from a number of wells with a reduced specific capacity. Light microscopy and electron microscopy were performed on undisturbed samples, and particle size distribution and chemical analyses were conducted on bulk samples. On the basis of study results, a new two‐pronged rehabilitation procedure was developed for seriously clogged wells. Initial findings indicate that the procedure offers both good immediate results and a significantly lower clogging rate over the long term. Hydron South Holland is conducting further research to prevent initial clogging and fine‐tune well drilling techniques and well design. Utilities experiencing well clogging in similar aquifer conditions can use these findings to optimize their own rehabilitation procedures or as a jumping‐off point for new research on well clogging and well design.
Physical and engineering properties of treatment plant residuals and disposal
Authors: Aldeeb Abdulrehman A. , Qasim Syed R. , Puppala Anand J. , Anderson Charles F.
Published: February 2018

In recent years, management of water treatment plant (WTP) residuals has become more expensive and complicated because of numerous federal, state, and local guidelines and regulations. In this study, alum‐coagulated residuals from two WTPs were tested for their engineering properties for ultimate land disposal as sanitary landfill cover material. After partial drying, the residuals were characterized by fine particle size distribution, high specific resistance, high plasticity index, low dry unit weight, and low shear strength. In this condition, the residuals were unsuitable for landfill cover application. However, residual properties were improved by blending the residuals with natural topsoil. The blending, performed at different ratios of the WTP residuals and the natural topsoil, resulted in a reduction of the plasticity index and an increase of the dry unit weight and shear strength. By varying the blending ratio, it was possible to achieve a soil mix that could be used as landfill cover material. In this research, a blend of 20% residuals and 80% natural soil provided a mix suitable for landfill cover application. Other residual management issues are also addressed.
Evaluation of indicators of fecal contamination in Groundwater
Authors: Atherholt Thomas , Feerst Eric , Hovendon Bruce , Kwak Jae , Rosen Joseph D.
Published: February 2018

Detecting fecal waste contamination of groundwater is usually accomplished by testing for fecal “index” or “indicator” bacteria. The authors examined 128 samples from 26 public groundwater sources in New Jersey and compared the ability of nine potential indicators to detect fecal contamination. Each sample was tested for heterotrophic plate count; total coliform (TC); fecal coliform (FC); Escherichia coli, enterococci, and Clostridium perfringens bacteria (100 mL); somatic and F+ coliphage (100 mL); and coprostanol (1 and 4 L). Data from a source with known contamination showed that the TC test was the most reliable indicator, followed by the FC test. Fecal pollution contains high concentrations of TC bacteria, but because some TC bacteria in the environment may not be of fecal origin, a positive TC test result should be followed by an FC, E. coli, or enterococci test to confirm contamination. The sanitary significance of the occasional presence of TC bacteria or coliphage without other fecal indicators was uncertain. Methods capable of analyzing 1‐L volumes should be investigated. A groundwater should be analyzed multiple times (i.e., 10 or more) to confidently determine its sanitary status.
AWWA's Source Water Protection Committee Outlines How To Maintain The Highest Quality Source Water
Authors: Gullick Richard W.
Published: February 2018

This article discusses the components of a source water protection program and the benefits a good program can offer. It lists some of the more important current and emerging topics and describes the AWWA Source Water Protection Committee, whose goal is to provide information to water utilities and other stakeholders to help them plan and implement effective source water assessment and protection programs. The article lists the various activities that the committee is involved in.
Small Communities Turn to Membrane Technology to Meet Water and Wastewater Discharge Standards
Authors: Galloway Merrillee
Published: February 2018

This article discusses problems that most small communities such as vacation resorts, colleges, and small towns have with their water supply that large water utilities don't encounter. One reason is that rural areas are more likely to use groundwater pumped from a well for their water supply and these wells can become depleted. Also, saltwater intrusion is a problem in wells that supply drinking water for seaside resort communities. Wastewater issues can become a problem as existing septic systems become insufficient as small communities experience growth. Many small communities lack the information and resources related to wastewater infrastructure and don't have the financial resources that large communities do. The article discusses membrane systems that are being used in small water systems, and examples are given of several resorts, small towns, and institutions that are using membrane technology.
keeping Legionella out of water systems
Authors: Sidari Frank P. , Stout Janet E. , Vanbriesen Jeanne M. , Bowman Ann Marie , Grubb Douglas , Neuner Alan , Wagener Marilyn M. , Yu Victor L.
Published: February 2018

Hospitals are often required to perform a supplemental disinfection of their water systems to protect individuals from hospital‐acquired Legionnaires' disease. The authors of this article recently studied one hospital where three cases of hospital‐acquired Legionnaires' disease were detected in less than two years. These cases were linked to Legionella colonization of the hospital's water system. Chlorine dioxide (ClO2) was considered a cost‐effective approach to disinfection given that ClO2 generators could treat the 23 buildings comprising the hospital complex from one central location. The authors evaluated the efficacy of maintaining a residual of 0.5 to 0.8 mg/L of ClO2 for Legionella control in the secondary distribution system of this 437‐bed hospital over a two‐year period. Monthly monitoring showed mean Legionella positivity at hot water outlets and cold building source water areas decreased from 23 to 12% and 9 to 0%, respectively (p< 0.05). ClO2 residuals decreased with increasing distance from the application point and temperature. Mean ClO2 concentrations were lowest in hot water outlets (0.08 mg/L) followed by cold water outlets (0.33 mg/L) and reservoirs (0.68 mg/L). Complete eradication (0% positivity) of Legionella was achieved after 1.75 years, and no cases of Legionnaires' disease were reported during this time.
Drinking Water Contaminant Regulation: —Where are We Heading?
Authors: Pontius Frederick W.
Published: February 2018

Since the US Environmental Protection Agency (USEPA) enacted the Safe Drinking Water Act (SDWA) in 1974, an increasingly complex series of rulemakings has transformed the US drinking water regulatory program into a labyrinth of requirements supported by a vast administrative superstructure. Furthermore, with each amendment of the SDWA, the paradigm applied to the regulation of drinking water contaminants has shifted. The financial and personnel demands imposed by implementation and compliance with existing and upcoming rules have strained the limited resources of water utilities, state agencies, and USEPA itself. In addition to summarizing the current regulatory program, this article delineates the patchwork quilt of requirements specified in the Stage 2 Disfectants/Disinfection Byproducts Rule and other upcoming regulations.
Benefit–Cost Implications of Multicontaminant Drinking Waters Tandards
Authors: Gurian Patrick L. , Small Mitchell J. , Lockwood J. R. , Schervish Mark J.
Published: February 2018

Evaluations of the costs and benefits of US drinking water standards typically consider only a single contaminant or class of contaminants. However, the US Environmental Protection Agency (USEPA) is in the process of formulating and implementing multiple new regulations, and drinking water systems will be expected to comply with all of them simultaneously. The joint effects of different regulations are not necessarily the sum of the effects of the individual regulations. In some cases, treating for one contaminant may remove other contaminants. In other instances, treating for one contaminant (e.g., pathogens) may make it more difficult to comply with regulations for other contaminants (e.g., disinfection byproducts). A simulation model was developed to assess the national costs and benefits of compliance with multiple drinking water standards. For each of the approximately 55,000 US community water systems, concentrations of raw water constituents, treatment type, and removal efficiencies were sampled from statistical models and used to compute finished water concentrations. Modeling the effects of different regulations at the same time and using the same modeling assumptions allowed the cost‐effectiveness of alternative regulations to be compared on an equal basis. For example, this study found that the revised arsenic maximum contaminant level (MCL) is more cost‐effective than the uranium MCL at reducing cancer risk. By facilitating more direct comparison of the cost‐effectiveness of different regulations, an integrated model can help utilities prioritize their regulatory options. In addition, a better understanding of the joint effects of different regulations may help USEPA and other stakeholders to design more effective overall regulatory programs.
Iron coagulation and direct microfiltration to remove arsenic from groundwater
Authors: Ghurye Ganesh , Clifford Dennis , Tripp Anthony
Published: February 2018

Arsenic (As) removal using ferric hydroxide coagulation followed by direct microfiltration without flocculation was investigated for an application in Albuquerque, N.M. Typically, the influent drinking water (unchlorinated) was contacted with ferric hydroxide for ≤20 s in a rapid mixer and passed through a membrane microfiltration unit with a nominal pore size of 0.2 μm. Variables investigated included pH, iron (Fe) dose, mixing time and energy, filtrate flux, and backwash interval. The pH and ferric dose were found to be the most important variables controlling As removal. As removal to low levels (<2 μg/L) was achieved using either a dose of 7 mg/L Fe without deliberate pH reduction or a smaller dose of 1.9 mg/L Fe after sulfuric acid addition to reduce pH to 6.4. Extended operation (three to five days) showed that consistent As removal was obtained without any membrane fouling. Both the backwash water and the dried sludge passed the toxicity characteristic leaching procedure test as a nonhazardous waste.
Hardwood–Based Granular Activated Carbon for Metals Remediation
Authors: Lima Isabel M. , Marshall Wayne E. , Wartelle Lynda H.
Published: February 2018

Hardwood waste such as oak chips is an abundant, high‐carbon content by‐product with little value other than for burning as fuel. This study optimizes conditions for the production of granular activated carbon, which has excellent metal ion adsorption properties, using oak chips as a source material. Oak chips were dehydrated with 30% phosphoric acid at 170oC and activated at 400–500oC in the presence of breathing air. Metal ion (Cu2+) adsorption capacities for two representative hardwood‐based carbons were 1.1–1.2 mmol Cu2+ adsorbed/g of carbon. Surface areas of the two carbons were 656 and 730 m2/g, respectively, and surface charges were 3.44 and 4.16 mmol H+ eq/g, respectively. These carbons were compared with several commercial metal‐ion‐adsorbing materials to determine their efficacy relative to the commercial samples. The comparative studies indicated that oak chip carbons had higher metal ion adsorption capacities than all of the commercial samples except for the materials containing carbon/cation exchange resin mixtures.
Factors for Success in New Technology Development
Authors: Maxwell Steve
Published: February 2018

This article discusses critical success factors for building a successful technology development company in the water industry. Much more is required for the economic success of a company than just a working or innovative new technology. Important business strategies are discussed, along with four major steps to the general technology development processing in the water industry.
Mixing and aging of water in distribution system storage facilities
Authors: Grayman Walter M. , Rossman Lewis A. , Deininger Rolf A. , Smith Charlotte D. , Arnold Clifford N. , Smith James F.
Published: February 2018

Mixing and aging are two related phenomena that affect the water quality changes that can occur within distribution system storage tanks and reservoirs. Long residence times depress disinfectant residuals and can promote bacterial regrowth, and uneven mixing can result in zones of older water. As a result, minimizing detention time and avoiding zones of water that remain in the storage facility for long periods of time should be implicit objectives in the design and operation of distribution system storage facilities. In this article, the authors present information and tools to assist water utilities in the design, retrofit, or operation of distribution system storage facilities so as to minimize the probability of seriously diminished water quality resulting from poor mixing and excessive aging.
role of chlorine and chloramine in corrosion of lead‐bearing plumbing materials
Authors: Edwards Marc , Dudi Abhijeet
Published: February 2018

A switch from free chlorine to chloramine disinfectant triggered problems with excessive lead in Washington, D.C., drinking water. High levels of lead originated in the service lines, but excessive lead was also derived from solder or brass plumbing materials. In many cases, the highest lead concentrations emerged from the tap after about 1 min of flushing—a troublesome outcome, given that routine public notification recommended that consumers flush for about a minute to minimize lead exposure. Bench‐scale testing found that chlorine reacts with soluble Pb+2 to rapidly precipitate a red–brown‐colored lead solid that was insoluble even at pH 1.9 for 12 weeks; this solid did not form in the presence of chloramine. Further experiments indicated that chloramines sometimes dramatically worsened lead leaching from brass relative to free chlorine, whereas new lead pipe was not strongly affected.
modeling membrane performance over time
Authors: Zhao Yu , Taylor James S.
Published: February 2018

A diffusion‐control solute mass transfer model was developed to describe permeate water quality over time of operation. The changing mass transfer characteristics of four low‐pressure reverse osmosis membranes were correlated to feed stream water quality in a 2,000‐h pilot study. Solute mass transfer coefficients (MTCs) were correlated to initial solute MTCs, solute charge, feedwater temperature, monochloramine loading, and organic loading (ultraviolet light at 254 nm). Independent data were used to validate the model. The model can be used to predict permeate water quality and sensitivity of permeate water quality to variations in temperature and organic and monochloramine mass loading.
Accuracy and Interferences for Enzyme‐Linked Immunoassay Tests for Atrazine
Authors: Adams Craig , Jiang Hua , McGuire Michael , Graziano Nicole , Roberson Alan , Frey Michelle
Published: February 2018

Enzyme‐linked immunosorbent assay (ELISA) methods have become a common alternative to gas chromatography methods for analyzing atrazine in raw and finished drinking water. This study investigated several leading ELISA atrazine test kits currently in use. This work demonstrates that although all the kits analyzed provided precise results, their accuracy varies greatly between kits and water matrixes. In most cases, the ELISA test kits provided positively biased results, although some negatively biased results were also observed. That is, the ELISA atrazine concentrations were usually greater than the actual concentrations. Although a part of this positive bias was because of cross‐reactivity with other chloro‐s‐triazines in the water matrix, much of the observed interference appeared to be related to natural organic matter, chlorination and/or quenching, and other factors. Even though the observed positive bias tends to cause the kits to provide a conservative result with respect to atrazine concentration, the role of ELISA test kits for regulatory purposes requires more study and discussion.
Colorado Ranch Must Replace 100% of Groundwater Withdrawals
Authors: Stiegler Mayo H.
Published: February 2018

The Supreme Court of Colorado has required an owner of ranchland in a substantially overappropriated river basin to replace 100% of the groundwater the ranch withdrew from the basin's aquifers.
Committee Report: Recent advances and research needs in membrane fouling
Authors:   AWWA Membrane Technology Research Committee
Published: February 2018

The article is the work of the AWWA Membrane Technology Research Committee. It was prepared by Isabel C. Escobar (chair), Eric M. Hoek, Christopher J. Gabelich, Francis A. DiGiano, Yann A. Le Gouellec, Pierre Berube and Kerry J. Howe with contributions from committee members Jason Allen, Khalil Z. Atasi, Mark M. Benjamin, Philip J. Brandhuber, Jonathan Brant, Yu‐Jung Chang, Michelle Chapman, Amy Childress, William J. Conlon, Trevor H. Cooke, Ian A. Crossley, Gil F. Crozes, Peter M. Huck, Sunil N. Kommineni (vice‐chair), Joseph G. Jacangelo, Ali A. Karimi, Jae‐Hong Kim, Desmond F. Lawler, Qilin Li, Lance C. Schideman, Sandeep Sethi, John E. Tobiason, Tai Tseng, Srinivas Veerapaneni, and Amy K. Zander.
Linking Water Quality to the Watershed: Developing Tools for Source Water Protection
Authors: Peckenham John M. , Schmitt Catherine V. , McNelly Jeffrey L. , Tolman Andrews L.
Published: February 2018

Watershed management has been called the “key to the future” by the US Environmental Protection Agency. Watersheds are widely recognized as one of the most effective tools for source water protection. Accordingly, the most recent amendments to the Safe Drinking Water Act mandate states to assess public water supply susceptibility to contamination. This article presents the process and results of Maine's Safe Water Assessment Program. The article examines how Maine's assessment process produced an inventory of threats, and it outlines how the state moved from inventory to action. The information presented in this article can be used as a tool to help small utilities find partners to work with them on source water protection. This guide is intended to help utility managers move from assessment to action by helping them understand the issues, locate assistance and experts, and plan appropriate protective actions.
Nitrification modeling in chloraminated distribution systems
Authors: Liu Suibing , Taylor James S. , Randall A.A. , Dietz John D.
Published: February 2018

This article describes a kinetic model for nitrification in a drinking water distribution system. Monod kinetics were used to develop a steady‐state plug‐flow kinetics model to describe the variations of ammonia, nitrite, and nitrate‐N concentrations in a chloraminated distribution system. Active ammonia‐oxidizing bacterial and nitrite‐oxidizing bacterial biomasses in the distribution system were determined using predictive equations within the model. The kinetic model used numerical analysis and was solved to predict ammonia, nitrite, and nitrate using C programming language for computers, which is similar to FORTRAN but simpler to use.
Jurassic Thinking
Authors: Hoffbuhr Jack W.
Published: February 2018

In his column, AWWA Executive Director Jack Hoffbuhr discusses what utilities will have to do to be effective in a rapidly changing environment that includes aging infrastructure, growing consumer demands, a changing workforce, crazy climatic conditions, and in many cases, insufficient water resources. Hoffbuhr states that the key is to transition from management to leadership, and that strategic thinking to identify alternate futures based on different scenarios is more effective than an over‐structured planning system. He also discusses expanding measures of success from merely being financially solvent and having a sound physical infrastructure to gauging how customer needs are met, fulfilling social responsibility to public health and the environment, and assisting employees with learning and growth.
Replacing polyphosphate with silicate to solve lead, copper, and source water iron problems
Authors: Schock Michael R. , Lytle Darren A. , Sandvig Anne M. , Clement Jonathan , Harmon Stephen M.
Published: February 2018

In 1990, the town of Hopkinton, Mass., instituted a polyphosphate sequestrant feed in two of its five wells to address colored water complaints caused by source water iron and manganese. Failure to meet the Lead and Copper Rule (LCR) action levels and continuing intermittent red water problems prompted the water utility to seek an alternative treatment strategy. After analyses of the water quality of the different wells, the scales on some lead service lines, the operational patterns, the location of lead service lines, and the distribution system configuration, a combination of sodium silicate (with chlorination) and sodium hydroxide addition at different wells was investigated. At study monitoring sites, an initial silicate dose of 25–30 mg/L elevated the pH from 6.3 to 7.1 and immediately resulted in a 55% reduction in lead levels and an 87% reduction in copper levels. An increase to a silicate dose of 45–55 mg/L elevated the pH to 7.5 and produced greater reductions in lead and copper. The treatment change reduced 90th percentile lead and copper levels by at least 95%, enabling compliance with the LCR. The aesthetic quality of the drinking water after treatment was equal or superior to the quality before treatment. The study showed that for many small and medium water systems with multiple wells and entry points, simultaneous overall corrosion control and sequestration of iron and manganese is possible, and it avoids the adverse drinking water/wastewater consequences associated with polyphosphate addition.
Pipe Section Reactor to Evaluate Chlorine–Wall Reaction
Authors: Digiano Francis A. , Zhang Weidong
Published: February 2018

A bench‐scale, pipe section reactor (PSR) was developed and tested to measure the decay rate of chlorine (Cl2) at the pipe wall, commonly described as “wall demand” but herein referred to as the chlorine–wall reaction. This experimental protocol is more convenient than pipe loop reactors that require a large laboratory and a large volume of water. The design allows investigation of the effect of velocity on chlorine–wall reaction. Two 6‐in. (152‐mm) diameter sections of old cast‐iron (CI) pipe and new cement‐lined ductile‐iron (DI) pipe were used. In addition to water velocity, the effects of water quality (corrosion rate, dissolved oxygen [DO], and pH) on the chlorine–wall reaction were also evaluated. The Cl2 decay rate was described by zero‐order kinetics for CI pipe. The zero‐order rate constant was larger at higher velocity (because of higher mass transfer at the pipe surface although a limit was reached), lower pH (because of faster corrosion rate), and lower DO (because of greater release of ferrous iron after removal of the oxidized layer at the surface). For the DI pipe section, the Cl2 decay kinetics were first‐order with respect to chlorine concentration.
Association between residual chlorine loss and HAA reduction in distribution systems
Authors: Speight Vanessa L. , Singer Philip C.
Published: February 2018

A goal of the proposed Stage 2 Microbial/Disinfection Byproducts Rules are to reduce peak concentrations of disinfection by‐products (DBPs) in distribution systems. Water utilities will be required to conduct an initial distribution system evaluation to select sampling locations that capture peak DBP concentrations. The selection of monitoring locations is difficult because trihalomethane (THM) and haloacetic acid (HAA) concentrations can vary over time and space in a distribution system. Maximum concentrations may not occur at the same location over time, and maximum THM and maximum HAA concentrations may not occur simultaneously at the same site. Although the maximum THM concentration often corresponds to the location with the maximum residence time, this does not hold true for HAA concentrations, which tend to reach a maximum value and then decline with increased residence time. Occurrence data for HAAs from several distribution system studies were compiled and analyzed to demonstrate variability in HAA concentrations. In these cases, under conditions of low residual chlorine or chloramine concentrations, HAA concentrations were low, even at locations with long residence times. In contrast, THM concentrations were generally high at these same sampling locations. HAA concentrations were often observed to decrease in storage tanks.
Physicochemical aspects of Cryptosporidium surrogate removal in carbon block filtration
Authors: Lau Boris L.T. , Harrington Gregory W. , Anderson Marc A. , Tejedor Isabel
Published: February 2018

As the final barrier before consumption, properly designed and operated point‐of‐use water treatment systems like carbon block filters are useful in protecting public health. This article evaluates the relative importance of adsorptive filtration, straining filtration, and cake filtration in the removal of nominal test dust (NTD) and latex microspheres, the latter being a Cryptosporidium oocyst surrogate, by carbon block filtration. Three different carbon blocks were tested, and only one of these was able to pass a National Sanitation Foundation (NSF) certification test. Surface charge characteristics can explain why two carbon blocks failed the test; however, they cannot explain why one carbon block passed the test. Scanning electron microscopy and energy dispersive X‐ray spectroscopy results together with the use of particle size distributions confirmed a lack of NTD penetration into the successful carbon block and suggest that cake filtration was the dominant NTD removal mechanism in this carbon block. Particle size analysis revealed that D15appears to be one of the determining factors in the passing the NSF certification test.
USEPA finalizes second Contaminant Candidate List
Authors: Scharfenaker Mark
Published: February 2018

This column discusses the finalization by the U.S. Environmental Protection Agency (USEPA) of the Second Contaminant Candidate List (CCL2) that includes 51 contaminants under consideration by the USEPA for possible future regulation. The article reports that the USEPA also plans to develop future CCLs using a more robust methodology recommended by expert panels from several government agencies and councils. The article provides a list of the 51 contaminants along with a chart of the CCL process recommended by the National Drinking Water Advisory Council workgroup. Supplemental internet resources are given.
The impact of filtrate turbidity on UV254 and SUVA254 determinations
Authors: Karanfil Tanju , Erdogan Ilke , Schlautman Mark
Published: February 2018

The main objectives of this research were to examine the effects of colloidal and particulate matter in freshwaters on dissolved organic carbon (DOC) and ultraviolet light absorbance at 254 nm (UV254) and to develop some guidelines for filtering freshwater samples with widely varying turbidities. More than 90% of the organic matter in the natural waters tested in this study was in the dissolved form, and filter cake formation did not have a significant impact on the DOC values of a sample. The experimental results showed that the level and characteristics of turbidity in a water sample, as well as the nature of pore structures and pore size distributions of a membrane filter selected for filtration, play important roles in UV254 and specific ultraviolet absorbance254 (SUVA254). Results indicated that when filtrate turbidities were below 0.3 ntu, filtration volume, filter cake formation, and pretreatment processes had no significant impact on DOC and UV254 determinations and thus on calculated SUVA254 values. When filtrate turbidities were >0.5 ntu, however, they increased the UV254 values (and also SUVA254) without causing an apparent impact on the DOC measurements. These findings suggest that a conservative criterion for the turbidity of a filtered UV254 sample, such as <0.3 ntu, should be adopted to minimize interferences on the results.
Preserving Sustainable Water Supplies FOR FUTURE GENERATIONS
Authors: Schlaman James C. , Kenel Pamela P.
Published: February 2018

Sustainability of the planet's water resources should always be a consideration when a water supply plan is developed. Demand for water is increasing and new supplies are becoming scarce, creating an increasingly urgent need to view water in an integrated, holistic manner. From this perspective, wastewater issues also become water supply issues. In this article the authors present results of their study, undertaken to raise awareness of sustainability issues and their applicability to water suppliers. The article discusses how water utilities should lead efforts to address sustainability issues and emphasizes that water suppliers must take an active role in managing water resources. Additionally, the authors discuss why water suppliers must increase their awareness of the scientific as well as practical issues associated with their water supply operations.
Bench‐scale evaluation of critical flux and TMP in low‐pressure membrane filtration
Authors: Choi Kevin Young‐June , Dempsey Brian A.
Published: February 2018

Critical flux has been defined as the permeate flux of a membrane system under which little or no fouling is observed. Exceeding critical flux results in rapidly increasing transmembrane pressure and fouling. This article describes bench‐scale techniques that can be used to measure critical flux and determine the effects of changing water quality on membrane performance. The bench‐scale technique also demonstrates the effectiveness of coagulation on low‐pressure membrane system performance. The critical flux test for low‐pressure filters could be considered the operational equivalent of jar testing in conventional water treatment plants. It is proposed that utilities and consultants should use similar bench‐scale critical flux measurements to assist in low‐pressure membrane system design, to modify operation during periods of changing water quality, and to determine the effects of coagulation or other treatments on low‐pressure membrane system performance.
New Directions in Lawn and Landscape Water Conservation
Authors: Vickers Amy
Published: February 2018

This article presents outdoor water use as a growing conservation challenge facing the United States. Roughly 8 billion gallons of water per day are devoted to lawn and landscape irrigation, a volume equivalent to 14 billion six‐packs of beer. Forward‐thinking water‐saving strategies to address these issues are presented.
An in‐depth investigation of Xeriscape as a water conservation measure
Authors: Sovocool Kent A. , Morgan Mitchell , Bennett Doug
Published: February 2018

The Las Vegas Valley in southern Nevada receives only an average of 4.5 inches of annual precipitation, has a yearly evapotranspirational water requirement of nearly 90 inches, and is one of the fastest growing metropolitan areas in the United States. Like most desert cities in the southwestern United States, typically 60‐90% of all water use by single‐family residences is for landscape irrigation. The Southern Nevada Water Authority partnered with the US Bureau of Reclamation to fund a five‐year study of the economic and conservation effects of converting turf landscapes to low‐water‐use Xeriscape?. Results indicated that conversion to xeric landscape produced significant water savings of 55.8 gal/sq ft annually. Homes that converted from turf grass to Xeriscape realized a 30% decrease in yearly total household water use, which equates to 96,000 gal annually. Xeriscape also provided savings in labor and money. Compared with owners of properties dominated by turf, the study group with xeric landscapes reported average annual reductions of 26.4 hours in labor and $206 in direct maintenance expenditures. Utilities may find it worth while to develop or strengthen incentive programs to foster conversion to Xeriscape among their residential and commercial customers.
An irrigation scheduling protocol for TREATED INDUSTRIAL EFFLUENT in the Chihuahuan Desert
Authors: Ruiz Alejandro , Sammis Theodore W. , Picchioni Geno A. , Mexal John G. , Mackay Wayne A.
Published: February 2018

As the population of southwestern New Mexico expands, land application of industrial and municipal wastewater is increasingly seen as a cost‐effective and environmentally safe water management technique. Yet virtually no management guidelines exist for scheduling land application of wastewater in semi‐arid climates of the United States. This article describes a web‐based methodology for scheduling wastewater irrigation in the Chihuahuan Desert. It also details how to input data that are specific to the region and climate into a spreadsheet program to schedule wastewater irrigation at rates that avoid adverse effects to the application site. A website helps utility managers outside of New Mexico use the methodology. An irrigation schedule created by this technique was tested over three years in Las Cruces, N.M. The land application was designed to maximize vegetative cover to increase the capacity of a site to serve as a sink for wastewater contaminants, minimize salt accumulation in the root zone, and avoid nitrate leaching into the groundwater. The step‐by‐step instructions provided here help utilities eliminate the guesswork of how much and when to apply water in a land application process.
A history of Water distribution
Authors: Walski Thomas M.
Published: February 2018

This article discusses the advances in science and technology that made our modern water distribution systems possible. The article begins with a brief history of early distribution systems, and chronicles the transition to modern day distribution systems. The science of hydraulics, piping, pumps, fire protection, metering, storage tanks, water quality considerations, hydraulic analysis, and computer applications are all discussed.
The evolution of microbiology in the drinking water industry
Authors: Rochelle Paul , Clancey Jennifer
Published: February 2018

The primary focus of this article is on microorganisms (pathogens) that cause disease such as Cryptosporidium spp., enteropathogenic E. coli, and enteric viruses. The article lists significant events in the history of drinking water microbiology, discusses the history of detection methods, and discusses the likely path of future developments in microbial sciences.
Effect of coagulation pretreatment on membrane filtration performance
Authors: Howe Kerry J. , Clark Mark M.
Published: February 2018

The effect of coagulation on microfiltration and ultrafiltration performance was evaluated in a recent laboratory study. The primary variables used in the study included source water, type of coagulant, coagulant dose, coagulation application conditions, and membrane material. Fouling was evaluated using flat sheet membranes in an unstirred filtration cell. As described in this article, a linear relationship between the removal of dissolved organic carbon (DOC), as measured by ultraviolet absorbance at 254 nanometres, and the reduction of fouling was observed. In addition, coagulation conditions appeared to influence the extent of fouling of the microfiltration membrane but had no effect on the ultrafiltration membranes. Low coagulant doses frequently caused greater fouling than no coagulation, but coagulant doses for enhanced coagulation always reduced fouling. Prefiltration was used to separate the effects of coagulation on particulate matter and DOC, and the results suggested that more than 80% of the fouling in these experiments was because of dissolved matter.
HAA removal by GAC adsorption
Authors: Tung Hsin‐Hsin , Unz Richard F. , Xie Yuefeng F.
Published: February 2018

Adsorption isotherm and field tests were conducted to investigate removal of haloacetic acids (HAAs) in the initial stage of granular activated carbon (GAC) filtration. Results from laboratory and field tests indicated that GAC adsorption plays only a minor role in overall HAA removal in GAC filters. In addition, HAAs (except trichloroacetic acid) had a much lower adsorption capacity than did trihalomethanes. Adsorption capacity for HAAs increased with increasing halogen number. Chlorinated HAA species had a lower adsorption capacity than did their brominated analogues. HAA removal in aged GAC filters may be attributable to biodegradation.
USING THE THEORY OF CONSTRAINTS to focus organizational improvement efforts: Part 1—Defining the problem
Authors: Reid Richard A. , Shoemaker Thomas E.
Published: February 2018

In this article, the first in a two‐part series, the theory of constraints (TOC) was applied to problems plaguing the maintenance system of the Albuquerque (N.M.) Water Utility Division. Using TOC premises and thinking‐process logic tools, the management team worked to pinpoint the primary constraint(s) limiting system performance. By creating a logic diagram (a current‐reality tree), team members were able to capture the cause‐and‐effect relationships responsible for the undesirable conditions and underlying core conflicts. TOC is a relatively new theory for identifying and understanding core problems within organizations. By demonstrating how the theory can be applied to a real‐world water provider, this article offers utility managers a solid, logic‐based approach to solving some of their more intractable and continually recurring problems.
Particle count and online turbidity interference from bubble formation
Authors: Scardina Paolo , Letterman Raymond D. , Edwards Marc
Published: February 2018

Bubble formation affects particle count and online turbidity measurements, but the water industry does not routinely employ a methodology for determining when bubbles are skewing measurements. In this study, bubbles were measured as particle counts in bench‐top laboratory experiments and at a full‐scale functioning utility. Particle counts decreased when the pressure in the measurement cell was increased during sampling, and in some cases, 46 ft (14 m) of water pressure was needed to suppress bubble formation. Failure to account for false particle counts can result in invalid conclusions about the efficacy of particle removal in water treatment. In laboratory experiments, bubbles caused spurious turbidity spikes, increasing turbidity and gas accumulation in the measurement cell of online turbidimeters. Instrument features such as electronic “bubble reject” and in‐line bubble traps can reduce the effect of bubbles on the measured turbidity, but in some cases they may aggravate the problem.
Factors affecting the removal of geosmin and MIB in drinking water biofilters
Authors: Elhadi Sarah L.N. , Huck Peter M. , Slawson Robin M.
Published: February 2018

Bench‐scale experiments were conducted using four parallel dual‐media filter columns containing biologically active anthracite or granular activated carbon media and sand. The factors under investigation were low‐ (8°C) and high‐ (20°C) temperature operations, geosmin and 2‐methylisoborneol (MIB) concentration, media type, and biodegradable organic matter (BOM) level. Source water consisted of dechlorinated tap water to which geosmin and MIB were added, as well as a cocktail of easily biodegradable organic matter (i.e., typical ozonation by‐products). Phase 1 experiments used a high BOM level (280 μg/L carbon [C]) to simulate water that had been subjected to ozonation before filtration. Phase 2 experiments used a low BOM level (28 μg/L C) to simulate nonozonated water. Factorial design experiments showed that all four main factors (temperature, concentration, media, and BOM level) were important to both geosmin and MIB removal. Temperature and media interaction and concentration and BOM level interaction were significant for geosmin removal only. Temperature and BOM level interaction as well as media and BOM level interaction were significant for the removal of both geosmin and MIB. Overall, removals of geosmin and MIB were lower in phase 2 (low BOM level), in particular in the anthracite media filters. Biomass levels in the filters appeared to have a significant effect upon the removal efficiencies of both odor compounds.
A Performance Index for Assessing Urban Water Systems: A Fuzzy Inference Approach
Authors: Bagheri Ali , Asgary Ali , Levy Jason , Rafieian Mojtaba
Published: February 2018

Assessing public utilities, such as urban water systems, can be extremely complicated because of the difficulties in quantifying system attributes. A framework for developing and aggregating performance indicators can assist the measurement and assessment process. In this article, research involving an integrated set of performance indicators applied to the urban water system of Tehran, Iran, is discussed. Specifically, a fuzzy inference model was used to aggregate indicators into an overall system‐performance index, which can be used to make comparisons among a large number of competing water system alternatives. The approach proposed in this article can also be applied to the assessment of other urban public utilities.
Alternative Methods For The Analysis Of Ndma And Other Nitrosamines In Water
Authors: Cheng Robert C. , Hwang Cordelia J. , Andrews‐Tate Cynthia , Guo Yingbo “Carrie” , Carr Steve , Suffet I.H. “Mel”
Published: February 2018

N‐nitrosodimethylamine (NDMA) and other nitrosamines have been reported in drinking and recycled water at low parts‐per‐trillion levels, both as contaminants and disinfection byproducts. Many of these nitrosamines cause cancer in animals and are probable human carcinogens. In this study, three existing analytical methods were expanded, refined, and validated for the analysis of NDMA and seven other nitrosamines in potable, waste, and recycled water. Method detection limits for a solid‐phase extraction (SPE) method and a cartridge SPE (CSPE) coupled with gas chromatography–tandem mass spectrometry were 0.7–0.8 ng/L for NDMA and 0.3–1.4 ng/L for other nitrosamines. The micro‐liquid–liquid extraction (MLLE) method that was developed used less volume and was effective at analyzing the different sample matrixes but yielded higher detection limits (2–4 ng/L). NDMA was the only nitrosamine detected in potable water; however N‐nitrosodiethylamine, N‐nitrosomorpholine, N‐nitrosopiperidine, N‐nitrosodi‐N‐butylamine, and N‐nitrosopyrrolidine were present in other matrixes tested. The SPE methods and the MLLE method have been submitted for inclusion in the next revision of Standard Methods for the Examination of Water and Wastewater, and the CSPE method will be submitted for approval in the future.
On–Line water quality parameters as indicators of distribution system contamination
Authors: Hall John , Zaffiro Alan D. , Marx Randall B. , Kefauver Paul C. , Krishnan E. Radha , Haught Roy C. , Herrmann Jonathan G.
Published: February 2018

The safety and security of drinking water distribution systems have recently generated considerable interest because of the credible concern that they could be compromised with chemical, biological, and radiological contaminants. In order to protect public health, the US Environmental Protection Agency initiated a program to investigate how changes in water quality parameters, which potentially indicate contamination, can be detected by real‐ or near real‐time sensors. The sensors investigated were off‐the‐shelf commercial products designed to monitor standard drinking water parameters such as pH, free chlorine, oxidation reduction potential (ORP), dissolved oxygen, specific conductance, turbidity, total organic carbon (TOC), chloride, ammonia, and nitrate. These sensors were mounted within a recirculating pipe loop and challenged with contaminants including secondary effluent from a wastewater treatment plant, potassium ferricyanide, a malathion insecticidal formulation, a glyphosate herbicidal formulation, nicotine, arsenic trioxide, aldicarb, and Escherichia coli K‐12 strain with growth media. Overall, the sensors that responded to most contaminants were those that monitored for free chlorine, TOC, ORP, specific conductance, and chloride. Generally, the technology used in sensor design or the particular manufacturer of the sensor did not affect the response characteristics. These results may help refine the role of water quality sensors, in conjunction with other data sources such as customer complaints and public health surveillance data, in a contamination warning system within a water distribution system.
Why Smart Managers Should Insist on—and Maximize Revenue from—Large Meter Testing
Authors: Jackson Jack
Published: February 2018

This article points out the importance to utilities of testing their large water meters since a significant portion of a utility's revenue is dependent on its larger meters. The article gives two examples of the effectiveness of a testing program. The Morristown Utility Commission in Morristown, Tennessee, saw a 12% jump in revenue after implementing a testing program for 50 large meters that account for 70% of the commission's revenue. The Cherokee County Water & Sewerage Authority in Georgia credits its large meter testing program as the primary driver for operating more accurate large meters and for decreasing the rate of water loss from 22% to 9%. The article includes an insert on the nuts and bolts of setting up a large meter testing program.