bluuebunny/crossref_metadata_2025_split huggingface dataset:
Toxicology and Drinking Water Contaminants
Authors: Stokinger Herbert E. 
Published: February 2018

The author finds it difficult to believe that the chloroform levels present in drinking water constitute a health hazard. The Natl. Cancer Inst. (NCI) reported chloroform to be carcinogenic in mice and rats when administered by mouth. The tumors occurred in highly debilitated animals, resulting from the use of a maximal tolerated chloroform dose to which significant numbers of the test animals succumbed and the survivors ended up in an unhealthy condition. On the other hand, feeding experiments conducted in another laboratory involving chloroform in lower doses (one sixth to one eighth those at the NCI) yielded no malignancies in mice. In addition, no dogs developed liver tumors after 7.5 years of exposure to 30 mg/kg/day of chloroform. Thus, chloroform must be regarded as an animal carcinogen of extremely low potency.Extrapolating animal data to man for the purpose of estimating the incidence of cancer in human populations can prove a fallacy. Biologic response to a toxic agent is not the same at low and high dosages—an assumption made by data extrapolators. The body has built‐in antagonists that can counteract the toxicity of foreign substances, including potential carcinogens. Natural and dietary sources of anticarcinogens also exist. Instances are cited where thresholds for cancer production have been demonstrated in animals and man. The threshold for tumor formation in rat livers ranges between 10 and 50 ppm in air of vinyl chloride. The incidence of liver tumors in vinyl chloride workers is extremely low and may be based genetically on inborn errors of metabolism.
Customer service gains a foothold
Authors: Harmon Rick 
Published: February 2018

Customer service reps can provide advantages to the public, and section customer service committees can provide advantages to utilities and one another.This Roundtable, moderated by Rick Harmon, AWWA'S manager of management development programs, took place Mar, 29, 1993, in Seattle, Wash. Participants were Patricia Colson, accounts services director for Seattle Water Department, 710 2nd Ave., Seattle, WA 98104;Jess Jones, assistant superintendent of the Commercial Division, Cincinnati Water Works, 4747 Spring Grove Ave., Cincinnati, OH 45232;Gene Seibel, manager of Tualatin Valley Water District, 1850 S. W. 170th Ave., Beaverton, OR 97005; Linda Faulkner‐Vaughn, director of customer and community affairs for Orange Water and Sewer Authority, 400 Jones Ferry Road, Carrboro, NC 27510; and John P. (Jack) Waters, customer operations manager for Chesterfield County Utilities, 6806 W. Krause Road, Chesterfield, VA 23832. Moderator Harmon is at AWWA, 6666 W. Quincy Ave., Denver, CO 80235.
Weathering the storm: water systems versus hurricanes
Authors: Murphy Maripat 
Published: February 2018

Hurricane Andrew ravaged southern Florida and left emergency planners with plenty of food for thought.The enormously destructive Hurricane Andrew flattened southern Florida last year and left a quarter of a million people homeless. Its co: is estimated to be $20 billion—an estimated $100 million of that damage to drinking water systems. In this wide‐ranging report, the author describes the frustrating range of problems water professionals faced a they began the lengthy process of recovery. The problems were legion, ranging from “uprooted” water mains and debris‐laden flood control canals to useless radio communication systems disabled because anten nas above the roof line had been knocked out. Bookkeeping became impossible because addresses no longer existed. Some employees wer injured; many lost their homes. AWWA's Florida Section offered finan cial help, and water professionals from unaffected utilities lent their expertise. This inventory of problems faced and solutions discovered will provide helpful ideas to emergency planners for water utilities.
Organonitrogen herbicides in the lower Kansas River basin
Authors: Stamer John K. , Zelt Ronald B. 
Published: February 2018

Atrazine, which is not readily removed by conventional treatment, may cause problems for water utilities in agricultural areas.To help managers, planners, and regulators determine when and where surface waters are likely to be adversely affected by organonitrogen herbicides, the authors analyzed various data on the distribution of these compounds in the lower Kansas River basin. They found that atrazine was the most frequently detected herbicide, was found in the highest concentrations, and was most likely to exceed the maximum contaminant level. The highest atrazine concentrations in the water were measured where the largest amounts of atrazine had been applied to the land, and median concentrations were higher in spring and summer than in fall and winter. Atrazine and chemically similar herbicides are not effectively removed by traditional water treatment. The Kansas State Board of Agriculture has established a pesticide management area to decrease the amount of atrazine that enters surface water.
The current regulatory agenda: an update
Authors: Pontius Frederick W. , Roberson J. Alan 
Published: February 2018

Major changes to USEPA's current regulatory agenda are anticipated when the SDWA is reauthorized.Three earlier articles (published in the Journal in February 1990,March 1992, and February 1993) reviewed the history, content,status, and schedule of regulations mandated by the Safe Drinking Water Act. Current developments related to these rules are presented in this article.
Managing the financial condition of a utility
Authors: Amatetti Edward J. 
Published: February 2018

Utilities that demonstrate the ability to best manage potential financial risks will be in the best position to obtain low‐cost financing in the future.The ability of a utility to obtain needed financing depends on its ability to convince the investor market of its creditworthiness. It follows that creditworthiness should be an explicit goal of utilities, like good customer service and an adequate supply of safe water. Managing creditworthiness effectively means managing future financial risk. The sources of financial risk in water utilities are discussed, as are ways to lower the financial risk profile over time. The minimization of risk through growth management, effective rate design, and the regulatory process is covered, and the changing role of the financial manager is explained.
Small systems and SDWA reauthorization
Authors: Shanaghan Peter E. 
Published: February 2018

USEPA's small systems coordinator summarizes key elements of the agency's report to Congress, emphasizing the issues of viability, low‐cost technology, and financing.Small systems issues have been a prominent feature of deliberations on the Safe Drinking Water Act (SDWA) since its initial formulation. In 1993 the US Environmental Protection Agency (USEPA) prepared a report to Congress that contained a detailed discussion of the SDWA compliance challenges faced by small water systems. This article focuses on three of the major small system issues identified in the report to Congress– viability, lower‐cost technology, and financing—and discusses how USEPA's reauthorization recommendations would address these issues.
Commercial labs: how accurate are they?
Authors: Clancy Jennifer L. , Gollnitz William D. , Tabib Zhanet 
Published: February 2018

In general, commercial laboratories show a lack of proficiency in testing for Giardia and Cryptosporidium.The authors conducted a blind survey of 16 commercial laboratories in order to evaluate their ability to test for Giardia and Cyptosporidium using the American Society for Testing and Materials (ASTM) method. After filters were spiked with approximately 740 Giardia cysts and Cyptosporidium oocysts or 500 cells of the alga Oocystis, they were sent to the laboratories for analysis. For the laboratories that submitted reports, Giardia cyst recoveries ranged from 0.8 to 22.3 percent, averaging 9.1 percent; Cyptosporidium oocyst recoveries ranged from 1.3 to 5.5 percent, averaging 2.8 percent. Four of the laboratories falsely reported the Oocystis as positive, four laboratories failed to recover the Giardia cysts, and six laboratories failed to recover the Cryptosporidium oocysts. Not all laboratories strictly followed the ASTM method. The majority of laboratories need to make improvements in one or more of the following areas: response to clients, adequacy of sampling equipment and directions for use, analytical methods, and data accuracy.
The pitting corrosion of copper
Authors: Edwards Marc , Ferguson John F. , Reiber Steve H. 
Published: February 2018

To solve or prevent copper pitting problems, it is first necessary to achieve a clearer understanding of copper corrosion theory, parts of which are currently not supported by practical experience.Some current theories of copper pitting are contradicted by practical experience. Although it has been theorized that chloride initiates copper pitting attack, simple experiments show that the presence of chloride ion actually tends to decrease the likelihood that pitting will occur. In contrast, sulfate plays no role in pitting theory, yet sulfate has consistently demonstrated a propensity to initiate and propagate copper pitting. New theories are required to reconcile pitting theory and practical observation in order to allow the rational mitigation of copper pitting problems. In addition, the presence of natural organic matter (NOM) in water supplies prevents or inhibits certain copper corrosion problems. As a result, recent efforts to remove NOM as a means of controlling disinfection by‐products may lead to increased copper corrosion problems.
Evaluating buoyant coarse media flocculation
Authors: Schulz Christopher R. , Singer Philip C. , Gandley Robert , Nix James E. 
Published: February 2018

In laboratory and field studies, a two‐stage buoyant coarse media flocculator provided settled water turbidities <2 ntu at loading rates as high as 12 gpm/sq ft.A new type of coarse media flocculator, using buoyant media instead of the heavier gravel in order to facilitate cleaning, was evaluated in laboratory and field studies. The results indicate that a two‐stage buoyant coarse media (BCM) flocculator provided effective treatment at higher loading rates and shorter residence times than are typically employed in designing mechanical flocculators. Source‐water quality and coagulant chemistry directly influenced flocculator performance and dictated the type of flocculator configuration selected. Tapering velocity gradients in the first‐stage flocculator enhanced performance. The authors recommend that additional studies be performed to develop reliable design and operating criteria for full‐scale BCM flocculators.
Long‐term effects of sludge application to land
Authors: Geertsema Wesley S. , Knocke William R. , Novak John T. , Dove Dennis 
Published: February 2018

Applying alum sludge to field research plots appears to have had no effect on the soil, groundwater, or growth of pine trees—even after 30 months.The purpose of this study was to evaluate the long‐term environmental effects of applying alum sludge to land. Investigations at the original field site included soil analysis, soil water monitoring, groundwater monitoring, and analysis of tissues from pine needles. No long‐term (30 months) effects were observed, and the authors conclude that alum coagulant sludges can be applied to forest lands at loading rates of at least 1.5 to 2.5 percent by dry weight without adverse effect.
Cost estimates for membrane filtration and conventional treatment
Authors: Wiesner Mark R. , Hackney John , Sethi Sandeep , Jacangelo Joseph G. , Laîé Jean‐Michel 
Published: February 2018

Membrane processes may offer small facilities a less expensive alternative for the removal of particles and organic materials.Costs of several ultrafiltration and nanofiltration processes are compared with the cost of conventional liquid‐solid separation with and without GAC adsorption for small facilities. Data on raw‐water quality, permeate flux, recovery, frequency of backflushing, and chemical dosage obtained from a pilot study were used with a previously developed model for membrane costs to calculate anticipated capital and operating costs for each instance. Data from the US Environmental Protection Agency were used to estimate conventional treatment costs. All of the membrane process calculations showed comparable or lower total costs per unit volume treated compared with conventional treatment for small facilities (<200,000 m3/d or about 5 mgd).
Effect of selected anions on copper corrosion rates
Authors: Edwards Marc , Meyer Travis , Rehring John 
Published: February 2018

Under conditions typical of drinking water, copper demonstrates a tendency toward increased corrosion that is inhibited only by the presence of chloride or bicarbonate at certain pH values.Copper passivation was examined in simple solutions that contained bicarbonate, chloride, perchlorate, nitrate, or sulfate at pH 5.5, 7.0, 8.5, and 10. Copper corrosion rates increased with aging in the presence of sulfate, nitrate, or perchlorate at all pH values, whereas copper passivated in the presence of chloride at pH ≥7.0. Bicarbonate ion was discovered to have a dual nature that was pH‐dependent, causing activation (increased corrosion rates) after aging at pH ≤7.0 and passivation at pH ≥8.5. Activation in the presence of bicarbonate was due to catalysis of oxygen reduction (cathodic) reactions, whereas sulfate, nitrate, and perchlorate increased the copper oxidation (anodic) reaction rates after aging.
Biodegradation of NOM: effect of NOM source and ozone dose
Authors: Goel Sudha , Hozalski Raymond M. , Bouwer Edward J. 
Published: February 2018

Batch experiments proved to be effective for obtaining a preliminary estimate of the biodegradation potential of NOM.Batch degradation experiments were conducted to evaluate the extent of biodegradation of natural organic matter (NOM) as a function of ozone dosage. Four NOM sources that might be encountered in drinking water treatment were characterized and tested. The biodegradability of all sources was enhanced as the ozone dose was increased from 0 to 7.3 mg ozone/mg total organic carbon (TOC). Increased ozonation resulted in cnsistently improved TOC removals for NOM souces having a large fraction of high‐molecular‐weight organics. Greater biodegradation was observed for the unozonated sources with lower UV‐absorpotion ‐to‐TOC rations and larger fraction of low‐molecular‐weight organics.
Measuring UV‐absorbing organics: a standard method
Authors: Eaton Andrew 
Published: February 2018

Under the Information Collection Rule, water utilities across the United States will gather data on UV‐absorbing organics in an attempt to correlate this parameter with the occurrence of disinfection by‐products precursors.The method described here was prepared by the Joint Task Group for Method 5910. It will be included in the nineteenth edition of Standards Methods but is being published now so that it will be available for use with the Information Collection Rule. The method is intended to indicate the aggregate concentration of UV‐absorbing organics, which may possibly be correlated with precursors of disinfection by‐products. Details of the experimental method, results and discussion, and quality control are included, as well as a description of the principle of the method and interferences. Interlaboratory precision data are shown.
Membrane air‐stripping: effects of pretreatment
Authors: Castro Kevin , Zander Amy K. 
Published: February 2018

Membrane air‐stripping shows promise for removing volatile contaminants from low‐pH and low‐chlorinewaters but is incompatible with ozonated waters or waters with high pH or high‐chlorine concentration.Microporous polypropylene hollow‐fiber membranes offer significant advantages over packed‐tower aeration for removing volatile organic chemicals. A laboratory study assessed the performance of membrane air‐stripping in continuous operation, while exposed to various pretreatments. Results indicate that membrane air‐stripping is compatible with low‐pH or low‐chlorine waters but not with waters of high pH or high‐chlorine concentration or those that are ozonated.
Evaluating NF for DBP control with the RBSMT
Authors: Allgeier Steven C. , Summers R. Scott 
Published: February 2018

A rapid bench‐scale membrane test was designed to capture critical aspects of full‐scale systems, particularly water flux and solute rejection, while maintaining the benefits of a bench‐scale system.At the center of the rapid bench‐scale membrane test (RBSMT) is a tangential‐flow flat‐sheet cell with recycle, which represents a differential element of a fullscale spiral‐wound nanofiltration element treating the average feed for a full‐scale system. The RBSMT incorporates operational parameters, such as recovery, pressure, crossflow velocity, and hydraulic conditions that approximate field‐scale operation. Four conventionally treated surface waters and one untreated groundwater were evaluated using the RBSMT. All of the waters tested would meet the Stage 1 requirements of the Disinfectants/ Disinfection By‐product Rule after nanofiltration, and the four surface waters would satisfy the Stage 2 requirements.
Earthquake lessons pay off in Sounthern California
Authors: Young Michael B. , III Edward G. Means 
Published: February 2018

Superior design standards, long‐term planning and preparation, and the development of in‐house repair capabilities helped MWDSC crews manage when the 1994 Northridge earthquake struck.After the Sylmar earthquake in 1971, the Metropolitan Water District of Southern California established emergency planningprocedures. In 1994, the Northridge earthquake in the same area put those preparations to the test. Much of the groundwork proved helpful: an Emergency Operations Center was activated within 40 minutes, and reconnaissance patrols completed their damage inspection within just 5 hours. In addition, a decision to buy heavy machining equipment paid off when crews were able to fabricate new pipe sections for the damaged Jensen Filtration Plant. Lessons learned in 1994 were that practice sessions do not duplicate the actual experience of an earthquake; human emotional response to disaster is unpredictable; agencies can expect outside assistance and do not need large stockpiles of extra equipment; and a business resumption plan needs to be established so office work can continue during an emergency.
LA's rehearsal for the big one
Authors: McReynolds Larry , Simmons Robert L. 
Published: February 2018

The Los Angeles Department of Water and Power fully restored service within five days of a destructive, 6.8‐magnitude earthquake.Although the 6.8‐magnitude Northridge earthquake in 1994 was not “the big one” Californians fear, it caused as much damage to the San Fernando Valley as would be expected from the big one—which, experts say, will have a magnitude of 8.0 or higher. This extensive damage occurred because the epicenter was in a large population center, and the quake caused record ground accelerations. The devastation tested the preparedness of the Los Angeles Department of Water and Power. Extensive damage to the water system left 500,000 people without water or fire protection, but water trucks supplied citizens at various locations while repair crews worked around the clock. Full service was restored within five days to 99 percent of customers.
Planning For Residential Fire Sprinklers
Authors: Walski Thomas M. 
Published: February 2018

Fire sprinkler installation raises complicated issues.Moderator of this Roundtable discussion was Thomas M. Walski, associate professor, Department of Environmental Engineering, Wilkes University, Wilkes‐Barre, PA 18766. Other participants were Jerry Dobrovolny, assistant waterworks engineer, City of Vancouver, 453 W. 12th Ave., Vancouver, BC V5Y 1V4; James D. Lake, technical services manager, National Fire Sprinkler Association (NFSA), POB 1000, Patterson, NY 12563; Kanwal Oberoi, water network engineer for the City of Edmonton Public Works, 8720‐106A Ave., Edmonton, AB T5H 0S3; and Joellen C. Thompson, hydraulic engineer, City of Grand Rapids Water System, 530 Ball Ave. N.E., Grand Rapids, MI 49503. The group met June 19, 1994, in New York, N.Y.
Corrosion control on the basis of utility experience
Authors: Dodrill Donna M. , Edwards Marc 
Published: February 2018

Although selection of corrosion control optimization strategies is more art than science, utility experiences can provide a basis for rational decision‐making.Utility experience under the Lead and Copper Rule was examined to provide improved insight into corrosion control. Average 90th percentile lead concentrations were highest in very‐low‐alkalinity waters (<30 mg/L as CaCO3) at utilities that did not use inhibitors; lead release was significantly reduced at higher alkalinities. Average lead releases were 20–90 percent lower for utilities using phosphate inhibitors (orthophosphates, polyphosphates, and blended phosphates) in very‐low‐alkalinity waters than for utilities not using inhibitors. At alkalinities of 30–74 mg/L as CaCO3 and at pH values > 7.40, it appeared that polyphosphate inhibitors had adverse effects on average lead release. Utilities with pH > 7.40 and high‐alkalinity waters had the highest copper concentrations. Phosphate inhibitors were usually beneficial in mitigating copper release; however, most benefits were at utilities with pH > 7.80 and alkalinity < 90 mg/L as CaCO3. Inhibitors appeared to adversely affect average copper release in some pH and alkalinity categories.
Network maintenance through analysis of the cost of water
Authors: Cabrera Enrique , Andrés Miguel , Planells Francisco 
Published: February 2018

A methodology based on the history of a system's pipe repairs—and incorporating cost analyses—indicates the best time to begin a leak detection program and when consideration should be given to replacing the network.A pipe's average life—normally between 40 and 100 years—is a highly variable parameter. This article proposes a method based on the history of repairs carried out on a network that allows an estimate to be made of the time a program for detection and repair of leaks should be started, as well as when the network should be replaced. Because some of the parameters are difficult to estimate, it is convenient to assess their influence on the results via sensitivity analysis.
Bench‐scale evaluation of GAC for NOM control
Authors: Summers R. Scott , Hooper Stuart M. , Solarik Gabriele , Owen Douglas M. , Hong Seongho 
Published: February 2018

Although these authors confirm that the RSSCT is able to predict the breakthrough behavior of full‐scale activated carbon columns, they emphasize the importance of obtaining a representative batch water sample for the RSSCT.The Information Collection Rule (ICR) will require that some utilities perform disinfection by‐product (DBP) precursor removal studies. The rapid small‐scale column test (RSSCT), a bench‐scale granular activated carbon (GAC) test designed to reduce time and costs associated with field‐scale studies, has been proposed as an alternative to evaluate GAC performance for the ICR. RSSCT scaling equations maintain similitude with full‐scale GAC systems, and therefore the RSSCT directly assesses the concentration breakthrough in a full‐scale GAC column. A review of past studies shows that the RSSCT has successfully predicted field‐scale performance for the control of natural organic matter and DBP precursors. The results of a current study emphasize the importance of obtaining a representative batch water sample for the RSSCT. A cost analysis based on using GAC to satisfy stage 1 and stage 2 requirements of the Disinfectants/Disinfection Byproducts Rule suggests that minimizing empty bed contact time will reduce capital costs associated with GAC contactors.