bluuebunny/crossref_metadata_2025 huggingface dataset:
The Influence of Ozonated Natural Organic Matter on the Biodegradation of a Micropollutant in a GAC Bed
Authors: De Waters Jan E. , DiGiano Francis A.
Published: February 2018

Biological activity on granular activated carbon (GAC) may significantly enhance the treatment process. Shifting the pathway for contaminant removal from adsorption to biodegradation reduces biodegradable organics and increases sorptive capacity for nondegradable or slowly degradable compounds. Biodegradation and adsorption of natural organic matter (NOM) were studied in a laboratory‐scale GAC reactor. Ozonation was found to encourage biofilm growth and biodegradation of NOM. Biofilm organisms grown on ozonated NOM readily degraded trace concentrations of phenol.
Pyrolysis–GC–MS for Investigating High‐Molecular‐Weight THM Precursors and Other Refractory Organics
Authors: Bruchet Auguste , Rousseau Claudine , Mallevialle Joel
Published: February 2018

Specific problems encountered during water treatment are known to be a function of the type of macromolecules present. The pyrolysis–GC–MS analytical technique described in this article shows the inadequacy of existing models to accurately reflect the complex mixture that comprises the organic matrix of natural waters. In fact, the highly condensed aromatic cores described by most of these models were determined by the research reported here to be minor constituents.
Assessing Toxicity of Drinking Water Contaminants: An Overview
Authors: Neal Robert A.
Published: February 2018

Chemical contaminants in drinking water can cause a variety of adverse health effects in humans, and a number of means are available to assess the toxicity of these chemicals. The most important means are epidemiology and animal tests. Epidemiology provides the most direct and least ambiguous information in that it assesses the actual occurrence of toxic effects in human populations exposed to chemical contaminants. Unfortunately, there are limitations to the use of epidemiology. Currently, experimental testing of animals is the most important means available to determine the toxicity of chemicals. A major limitation of these tests is the uncertainty about their applicability to humans. This uncertainty extends not only to differences in the qualitative responses of animals and humans to chemicals but more particularly to differences in the degree of response to various exposure levels.
Viewpoint of a Flying Philosopher
Authors: Mannion John B.
Published: February 2018

In a fictional conversation with an airplane companion, Mr. Mannion points out that there must be some compromise on the regulatory front. Although the wisest, most just decisions are not found on middle ground, acceptable decisions are found there; pragmatic political decisions are found there. The water industry will accept requirements they don't agree with, but more important, they are improving their water treatment and operations for positive reasons, not simply because of the regulatory club being waved at them.
The Effects of Temperature on Turbulent Flocculation: Fluid Dynamics and Chemistry
Authors: Hanson Adrian T. , Cleasby John L.
Published: February 2018

One of the primary objectives of the research described here was to identify the best available measure of the intensity of turbulence with a view to correcting the mixing intensity of the flocculation process to compensate for temperature effects. It was concluded, however, that no one measure of turbulence intensity is better than another. The authors observed that flocculation efficiency at 20°C is not sensitive to impeller geometry, but at 5°C impeller geometry is much more important. A turbine impeller caused much more floe breakup than a stake and stator impeller. With metal coagulants, the use of constant pOH is appropriate for correcting system chemistry for temperature effects. Alum floc was significantly weaker than iron floc under all conditions tested.
Coliform Regrowth in Drinking Water: A Review
Authors: LeChevallier Mark W.
Published: February 2018

With monitoring changes required by the US Environmental Protection Agency's 1989 coliform rule, the problems associated with coliform regrowth in finished drinking water are increasing. This article reviews the types of regrowth phenomena and the analytical evidence for regrowth in distribution system pipelines. It also considers factors that influence bacterial regrowth, including environmental factors, bacterial nutrients, disinfectant residuals, corrosion and sediment accumulation, and hydraulic effects. Methods for controlling bacterial regrowth, including effective treatment and monitoring, flushing and mechanical cleaning, disinfection, corrosion control, and nutrient control, are examined, and the advantages of—and concerns about—using biological treatment are discussed.
God Bless You, Walter Cronkite
Authors: Mannion John B.
Published: February 2018

This article reviews the videotape, “Big Fears, Little Risks,” which deals with contaminants in drinking water. Acknowledging the widespread public concern about the threat of cancer posed by the exposure to trace amounts of manmade chemicals, the video explores the scientific basis for such fears and comes to the conclusion expressed succinctly in its title. Mr. Mannion praises the narrator, veteran newscaster Walter Cronkite for taking on a controversial topic.
LETTERS
Authors: Cohoon J. Larry
Published: February 2018

The chief executive officer of the company manufacturing the Colilert(R) presence‐absence test for coliforms argues the findings of a study conducted by researcher Betty Olson. The results of Olson's research were briefly described in “Update–Researcher Challenges Efficacy of E. coli Analytical Technology” (Journal AWWA, September 1990).
Conference Summary: Practical Aspects of the Design and Use of GAC
Authors: Oxenford Jeffrey L. , Lykins Benjamin W.
Published: February 2018

This article is based on papers presented at a 1989 conference on the design and use of granular activated carbon (GAC) systems. The conference was cosponsored by the AWWA Research Foundation and the US Environmental Protection Agency. Topics covered include reasons for the use of GAC, alternatives to GAC, determining system size, design considerations, cost considerations, case histories, and current and future research.
SDWA Reauthorization
Authors: Pontius Frederick W.
Published: February 2018

Articles in this section of the Journal are dedicated to providing current information about legislative and regulatory developments pertinent to the drinking water industry. They address needs and concerns of water utilities from a practical standpoint; they are not intended to reflect official positions or policies of AWWA. Frederick W. Pontius, associate director for regulatory affairs, prepared this article on the upcoming reauthorization of the Safe Drinking Water Act and coordinates development of future articles. Pontius monitors and evaluates legislation and regulations that affect the drinking water industry, prepares official AWWA statements on drinking water issues, and represents the association at meetings, workshops, and study groups.
Network Analysis From Planning, Engineering, Operations, and Management Perspectives
Authors: Cesario A. Lee
Published: February 2018

Network analysis can be used by planners in the design of water systems, by engineers to size facilities, by operators in their daily decision‐making, and by managers to develop operating strategies and implement programs. Proper use of network analysis helps these utility personnel do their jobs more efficiently because it allows them to test system performance capabilities through simulation of the real system.
The Impact of the Surface Water Treatment Rule on Groundwater
Authors: Hiltebrand David J. , Chowdhury Zaid K. , Wancho Linda A.
Published: February 2018

The Surface Water Treatment Rule (SWTR) requires that all community and noncommunity water supply wells, springs, and infiltration galleries be evaluated to determine whether they are under the direct influence of a surface water. Those groundwater supplies that are found to be under the direct influence of a surface water will be subject to the requirements of the SWTR. This determination will have a significant impact on many existing water utilities and on the development of new supplies. The guidance manual for the SWTR provides a general outline of a procedure that can be used to make the determination of direct influence. This procedure was applied to two groundwater supplies.
Variations in Organic and Organoleptic Water Quality During Treatment of Artificially Recharged Groundwater
Authors: Bruchet Auguste , N'Guyen K. , Legrand M.F. , Mallevialle Joël
Published: February 2018

The objective of the study described here was to find statistical relationships between taste and odor descriptors and specific volatile organics in recharged groundwater. It was shown that the recharge process itself, as well as treatment, improved the organoleptic quality of the water. The volatile organics load decreased significantly during recharge and nitrification but increased again during oxidation steps. Thus, the improvement in organoleptic quality cannot be related to a change in total organics load but rather to the fate of specific compounds during treatment.
The Effect of Sulfur‐Based Reducing Agents and GAC Filtration on Chlorine Dioxide By‐products
Authors: Dixon Kevin L. , Lee Ramon G.
Published: February 2018

Experiments were performed to determine the effect of granular activated carbon (GAC) filtration and sulfur‐based reducing agents on chlorite and chlorate ions in water. It is concluded that neither GAC filtration nor sulfur‐based reduction is a feasible means of removing chlorine dioxide by‐products.
Comparing Ozonation and Membrane Separation for Color Removal and Disinfection By‐product Control
Authors: Tan Lo , Amy Gary L.
Published: February 2018

This article reports the results of applying ozonation and membrane treatment to a groundwater source containing significant levels of color and disinfection by‐product (DBP) precursors. Although both treatments provided effective removal of color, greater levels of DBPs were associated with the ozone treatment—after postchlorination. The effective DBP precursor removal provided by membrane separation of this groundwater source indicates that membrane processes are a promising treatment technology for complying with the more stringent DBP regulations that are expected in the near future.
Locating Monitoring Stations in Water Distribution Systems
Authors: Lee Byoung H. , Deininger Rolf A. , Clark Robert M.
Published: February 2018

Water undergoes substantial changes in quality between the time it leaves the treatment plant and the time it reaches the customer's tap, making it important to select monitoring stations that will adequately monitor these changes. But because there is no uniform schedule or framework for monitoring under the Safe Drinking Water Act, the degree of variability among monitoring requirements poses both management and technical barriers to states and water systems ultimately responsible for implementation of the regulations. Systematic and quantitative guidelines are provided here for locating monitoring stations. By using the concept of pathways, the authors applied the concept of coverage and inferred the qualify at an upstream node from the qualify at a downstream node.
Field‐Testing Distribution Water Quality Models
Authors: Clark Robert M. , Grayman Walter M. , Goodrich James A. , Deininger Rolf A. , Hess Alan F.
Published: February 2018

This article briefly reviews an extensive field study by the US Environmental Protection Agency and the North Penn Water Authority, which resulted in the development of a series of models to investigate contaminant propagation in a water distribution system. The application of one such model to the exploration of contaminant movement in the distribution network of Cabool, Mo., is explained. An extension of this work to a large water utility–the South Central Connecticut Regional Water Authority–is also discussed.
The Federal Drinking Water Program: Friend or Foe?
Authors: Kelley William A.
Published: February 2018

The author believes the federal approach to regulating water quality is undesirable because it reacts to a problem rather than prevents it. State engineers are forced to assume a clerical role dictated by the US Environmental Protection Agency, instead of providing technical assistance that would prevent noncompliance. As technical assistance programs dwindle, more regulatory violations occur, creating the need for more enforcement action, which steals time from technical assistance efforts. In addition the US Environmental Protection Agency does not have enough money to support the regulations it promulgates. While Senator Henry Waxman (D‐California) castigates the USEPA and proposes exorbitant lead regulations, the states are crippled by a horrendous administrative workload. The author concludes that the federal government should be involved in drinking water program only to the extent of research and development of drinking water standards, leaving decisions on implementation and enforcement to the states. Or, the federal government should fund state programs to allow preventive health work over and above the federal agenda.
Integrating Conservation and Water Master Planning
Authors: Macy Peter P.
Published: February 2018

Incorporating conservation into a master plan involves a risk of lost revenues, uncertainty as to exact long‐term savings, and increased operating budgets to implement the programs. Utilities should, however, see a net decrease in costs because properly designed and implemented conservation programs help maximize efficiency of existing supplies, which decreases operation and maintenance expenses and capital costs. Conservation can also help satisfy environmentalists and regulators whose cooperation may be needed to obtain future water projects.
Estimating the Effects of Conservation on Demand During Droughts
Authors: Little Keith W. , Moreau David H.
Published: February 2018

A primary goal of drought management is the reduction of water demand through short‐term conservation measures. To accurately judge the effectiveness of these measures, it is necessary to estimate what the demand would have been in the absence of conservation. A daily demand model developed for that purpose is presented in this article. The model uses Almon lags to account for lagged meteorological variables and includes an autoregressive error term. The model is applied in two case studies to estimate baseline demands for comparison with actual demands during the drought of 1986 in the southeastern United States.
Predicting the Formation of DBPs by the Simulated Distribution System
Authors: Koch Bart , Krasner Stuart W. , Sclimenti Michael J. , Schimpff Warren K.
Published: February 2018

A simulated distribution system (SDS) method has been developed to predict the amounts of disinfection by‐products (DBPs) that would form in a distribution system. The parameters (chlorine dosage, incubation temperature, and incubation holding time) of the method are chosen to simulate the conditions of the treatment plant and the distribution system. A study was conducted on the Metropolitan Water District of Southern California's distribution system at a time when free chlorine was being used in the distribution system. A second study was conducted on water from a utility in the eastern United States. Both studies showed good correlation between the SDS samples and the samples collected from the distribution systems.
Disinfectant–Disinfection By‐product Rule Update
Authors: Pontius Frederick W.
Published: February 2018

Articles in this section of the Journal are dedicated to providing current information about legislative and regulatory developments. They address needs and concerns of water utilities from a practical standpoint; they are not intended to reflect official positions or policies of AWWA. Frederick W. Pontius, AWWA associate director for regulatory affairs, prepared this overview of the Disinfectant–Disinfection By‐product Rule and coordinates development of future articles. Pontius monitors and evaluates legislation and regulations that affect the water industry, prepares official AWWA statements on drinking water issues, and represents the association at meetings, workshops, and study groups.
Using Regression Analysis to Project Pumpage
Authors: Rhoades Stephen D. , Walski Thomas M.
Published: February 2018

The city of Austin, Texas, Water and Wastewater Utility has used regression analysis to project water pumpage. It is a reasonably accurate, easy to learn and use, and inexpensive technique; it does not require an unusual amount of data; the explanatory variables and regression results can be quickly checked for statistical significance; and the input data can be easily modified. The fact remains, however, that regression cannot completely explain a complicated, multifaceted process. Also, there are limits to refining the predictions.
Using Anion Exchange Resins to Remove THM Precursors
Authors: Kim Philip H.‐S. , Symons James M.
Published: February 2018

This study investigated the control of trihalomethanes (THMs) with ion exchange by comparing the THM formation potentials of the organic fractions in the influent to three column systems. The results showed that the smallest organic fraction, <0.5K apparent molecular weight (AMW), was most reactive with free available chlorine. With the ion exchange system, the l–5K‐, 0.5–lK‐, and <0.5‐AMW organic fractions produced the majority of THMs, whereas with the granular activated carbon (GAC) and the combined ion exchange–GAC systems, the <0.5‐AMW fraction produced most of the THMs. The authors conclude that regeneration of the resin of the ion exchange column at sulfate breakthrough, in combination with a GAC column, will produce a water very low in THM formation potential.
Potential Impact of Water‐Efficient Plumbing Fixtures on Office Water Consumption
Authors: Behling Patrick J. , Bartilucci Nicholas J.
Published: February 2018

A July 1989 amendment to the New York State Plumbing Fixture Law of 1980 requires that all buildings constructed or renovated after 1992 be provided with plumbing fixtures that are “water‐efficient.” This article describes a fixture‐use procedure developed for estimating water consumption in office buildings and the utilization of the procedure to determine the reductions in water usage possible through the installation of water‐efficient fixtures. Reductions of between 44 and 69 percent are estimated for water‐efficent plumbing fixtures compared with older, conventional fixtures.
‘Reg Neg’ Considered for D–DBP Rule
Authors: Pontius Frederick W.
Published: February 2018

Departing from tradition, USEPA's Office of Ground Water and Drinking Water (OGWDW) is considering and intends to proceed with developing a proposed disinfection‐disinfection byproduct (D‐DBP) rule using negotiated rule‐making, also known as “regulatory negotiation” or “reg neg.” This would be the first time a drinking water regulation would be drafted using the reg‐neg process since USEPA's reg‐neg process began in 1983. USEPA has been working diligently for many years on the technical aspects of the D‐DBP rule. The rule will limit concentrations of disinfectants and their byproducts in drinking water. These limits conflict with other rules that ensure minimum levels of disinfection to prevent waterborne disease. Limits set under the D‐DBP rule must ensure that water systems can effectively control both the level of DBPs and microbials. USEPA views a negotiated rule as being beneficial in helping people understand the complexities of the risk‐risk trade‐off issues and in reaching a consensus on a sensible regulation for the short‐term until results of additional research are available. A notice of intent to form an advisory committee for the D‐DBP rule was published. Key issues identified by USEPA to be addressed during the negotiations are listed, and a tentative list of the parties who have initially been selected to participate on the advisory committee is given.
Technical Note: Comparing Predicted and Observed Concentrations of DBPs
Authors: Greiner Anthony D. , Obolensky Alexa , Singer Philip C.
Published: February 2018

The authors of this technical note conducted a limited survey of disinfection by‐product (DBP) formation in North Carolina drinking waters. In addition to examining statistical relationships among the various DBPs, these researchers compared measured values with predictions calculated using part of the model developed by Harrington et al, described in the article beginning on page 78.
Proposed Sulfate MCL Reconsidered
Authors: Pontius Frederick W.
Published: February 2018

The Safe Drinking Water Act (SDWA) as amended in 1986 requires the U.S. Environmental Protection Agency (USEPA) to regulate sulfate. USEPA proposed a maximum contaminant level (MCL) July 25, 1990, for sulfate at 400 mg/L or 500 mg/L in the Phase V proposal. The agency decided to reconsider the regulatory approach for sulfate when Phase V was promulgated July 17, 1992.
MF–PAC for Treating Waters Contaminated With Natural and Synthetic Organics
Authors: Pirbazari Massoud , Badriyha Badri N. , Ravindran Varadarajan
Published: February 2018

Microfiltration (MF) and powdered activated carbon (PAC) adsorption were combined to treat waters contaminated with organic compounds. The PAC mitigates the effects of membrane fouling and concentration polarization by removing dissolved organic matter such as humic substances. The investigation used trichloroethylene (TCE) as a model contaminant and deionized distilled water and California Aqueduct water as background solutions. Removals of >99.8 percent of TCE and >60 percent of dissolved organic matter were achieved. Steady‐state permeate fluxes of 10‐20 m3/m2/d (250‐500 gpd/sq ft) were easily maintained. The total cost of treatment with MF–PAC was estimated to be $1.27 per 1,000 gal of treated water. A three‐layer membrane transport model provided a qualitative appreciation of the MF–PAC
Convincing the Public That Drinking Water Is Safe
Authors: Glicker Joseph L.
Published: February 2018

Human beings are not particularly rational, and one way in which that fact is apparent is how people perceive issues of risk and safety. Risk perception is influenced by complicated social, cultural, and psychological factors as well as by objective information. Water, which is essential to life, has a unique role in people's emotional associations. Notions of water contamination convey threats of sickness; notions of water purity convey suggestions of health and safety. Heightened public awareness about environmental problems has magnified people's concern about the quality of drinking water, even in the absence of any degradation of that quality. Utilities should respect the concerns, values, and wisdom that are inherent in people's perceptions of risk. The issue of control is fundamental in risk perception, and so it is important to include in the utility's decision‐making process those affected by or concerned with the decisions. Water professionals who understand risk perception can improve a utility's communication with the public and the news media. The author provides examples of how the Portland, Ore., Water Bureau has put these guidelines into practice.
Removing Color From a Groundwater Source
Authors: Tan Lo , Sudak Richard G.
Published: February 2018

The organics and inorganics rejection characteristics of eight types of reverse osmosis membranes operating on a source of highly colored groundwater in Orange County, Southern California, were determined. All eight membranes were capable of removing color from groundwater. Additional long‐term testing of four membranes—two brackish water (BW) and two softening–nanofiltration (NF) membranes—was carried out at relatively high flux rates and increased recovery. These membranes produced a color level of 3 pcu or less, far below the current drinking water standard of 15 color units. Trihalomethane formation potential was effectively removed by both types of membrane. The NF membranes were more energy efficient than the BW membranes.
Iron and Manganese Sequestration Facilities Using Sodium Silicate
Authors: Robinson R. Bruce , Reed Gregory D. , Frazier Brett
Published: February 2018

Field studies were conducted at five water systems that used sodium silicate and chlorine to sequester iron and manganese. Sequestering was generally successful in four of the systems but was unsuccessful in one system that was not adding the silicate and chlorine nearly simultaneously. Iron and manganese did precipitate in hot water heaters, with no apparent red water at the tap and few customer complaints. Higher iron concentrations required less than proportionately higher dosages of silicate, and when water was stored in reservoirs for long periods of time, customer complaints seemed to rise. Total yearly chemical costs for silicate and chlorine were $1.25–$1.75 per person in 1985 at the two Canadian systems. Of this cost, $1.03–$1.14 perperson peryear was for silicate. Silicate dosages can be chosen by filtering treated‐water samples through a membrane filter and increasing the dosage upward until the filter paper is not discolored.
Estimating the Cost of Compliance With the Drinking Water Standard for Radon
Authors: Raucher Robert S. , Drago Joseph A.
Published: February 2018

Compliance with recently proposed maximum contaminant levels for radon is likely to involve a significant expenditure for the US public water supply industry. More than 30,000 utilities are expected to find that their groundwater supplies exceed the proposed limit of 300 pCi/L. The authors of this article have estimated that the costs of installing and operating radon removal technologies across the United States will amount to $2.5 billion/year, with more than two thirds of those costs being borne by the very small water systems that serve 500 or fewer people.
National Survey of Drinking Water Standards and Guidelines for Chemical Contaminants
Authors: McGeorge Leslie J. , Krietzman Sandra J. , Dupuy Carolyn Jean , Mintz Bruce
Published: February 2018

Many states have become involved in the process of developing drinking water standards or guidelines for contaminants in drinking water. In 1985 the US Environmental Protection Agency (USEPA), in cooperation with a small number of state agencies, formed the Federal–State Toxicology and Regulatory Alliance Committee (FSTRAC). Now, a majority of state drinking water and risk assessment programs have joined the USEPA for the purposes of exchanging information on the risk assessment of drinking water contaminants and improving the coordination of federal and state drinking water risk assessment and standard‐setting activities. l?XRAC conducted an extensive survey of the 48 primacy states, Puerto Rico, and the USEPA for information on each drinking water program, including existing and planned standards or guidelines for chemical contaminants as of January 1989. The bases for these standards and guidelines were also requested from each state, as well as an explanation of which factors besides risk assessment (i.e., treatment feasibility, cost) were used in the standard‐setting process.
Defining Best Available Technology
Authors: Pontius Frederick W.
Published: February 2018

Articles in this section of the Journal are dedicated to providing current information about legislative and regulatory developments. They address needs and concerns of water utilities from a practical standpoint; they are not intended to reflect official positions or policies of AWWA.
Removing Trace‐Level Organic Pollutants in a Biological Filter
Authors: Manem Jacques A. , Rittmann Bruce E.
Published: February 2018

Laboratory‐scale biofilm reactors simulating a full‐scale nitrification filter were challenged with xenobiotic contaminants frequently encountered in water supplies. Phenol and mono‐ and dichlorophenols were removed immediately (by up to 92 percent), with increasing influent concentration reducing the percentage removal. Trichlorophenols were not biodegraded. Mono‐ and dichlorobenzenes were also removed (up to 81 percent), but an enzyme‐induction period of 8–20 h was required before biodegradation became significant. In many cases, feeding of an easily degraded organic substrate (acetate) increased removals of the xenobiotics by a relatively small amount. This result suggests that unidentified background organic material and soluble microbial products generated by nitrifying bacteria allow the accumulation of bacteria able to degrade a range of xenobiotic compounds.
Using Inclined Cascade Aeration to Strip Chlorinated VOCs From Drinking Water
Authors: Boyden Brace H. , Banh Duong T. , Huckabay Houston K. , Fernandes Joseph B.
Published: February 2018

Inclined cascade aeration (ICA) was effective in removing 10 chlorinated volatile organic chemicals (VOCs) from drinking water at liquid loadings of 5 gpm/ft (1.04 L s–1/m) to 15 gpm/ft (3.1 L s–1/m). Overall mass transfer (or desorption) coefficients (KLav) were an order of magnitude larger (0.08–0.54 s–1) than those reported for packed‐tower aeration. A curve fit of the experimental data for all 10 VOCs with the equation KLav = 0.019 + 0.091 (Hp)$f14(sin θ)$, in which Hp is the Henry's law constant (atm) and θ is the angle of inclination, yielded desorption coefficients within ± 18 percent of experimental values. A cascade angle of 60° was found most efftcacious for compounds with Hp values >300 atm; compounds with Hp values <300 atm were most effectively stripped at yet steeper angles.
Pilot Testing a Limestone Contactor in British Columbia
Authors: Benjamin Lawrence , Green Ronald W. , Smith Anita , Summerer Stephan
Published: February 2018

A pilot‐plant‐sized limestone contactor was constructed at Port Simpson, B.C., and was evaluated for its ability to treat the water supply (low‐pH, low‐alkalinity water from a creek source) for corrosion control and to condition it for flocculation. Conducted over two months, detailed testing of the limestone contactor involved evaluating performance when it was open and when it was closed to the atmosphere, at various contact times, and at a wide range of flows. Results show that a limestone contactor is effective in treating Port Simpson water for corrosion control and that performance did not deteriorate during continuous operation for 20 months. Although the raw water samples tested had a limited range of color, results showed that the contactor is effective for conditioning water for flocculation to remove color.
Comparing Defined‐Substrate Coliform Tests for the Detection of Escherichia coli in Water
Authors: Covert Terry C. , Rice Eugene W. , Johnson Scott A. , Berman Donald , Johnson Clifford H. , Mason Paralee J.
Published: February 2018

Two commercially available defined‐substrate coliform tests were compared with EC medium plus 4‐methylumbelliferyl‐β‐D‐glucuronide (MUG) for detecting chlorine‐exposed Escherichia coli in spiked water samples. Statistical analyses of the test results indicated no significant differences in detection of E. coli between the Autoanalysis Colilert test and EC medium with MUG. There were, however, significant differences in detection of E. coli between the ColiQuik test and EC medium with MUG in the free‐chlorine‐exposed pure culture studies and when all the data were combined. All methods were capable of detecting 1 cfu/l00 mL of E. coli.
Workforce Literacy in the Water Utility Industry
Authors: Marlowe Herbert A. , Beaudet Bevin A.
Published: February 2018

Literacy in the utility workplace is especially critical because of the dramatically changing nature of the utility business. Thus, a key question is what the literacy levels are among utility employees. But because the empirical data required to answer this question are not available, the four studies reported in this article were conducted. The data reported here clearly indicate that the literacy levels of operations and maintenance personnel at a Florida utility are not adequate for the demands currently placed on them, much less the higher demands anticipated in the future.
Accommodating the Biological Clocks of Shift Workers
Authors: Felton Geraldene , Kruckeberg Thomas , Moreno Edward
Published: February 2018

For this study the authors investigated temperature rhythms, sleep patterns, dietary patterns, individual characteristics, and strategies to limit biological rhythm problems and adverse health outcomes associated with shift work. To reveal how circadian (24‐hour) patterning affects people who operate a water treatment plant, four subjects, three of whom rotated shifts around the clock, were studied for three weeks. All subjects showed circadian rhythmicity in their temperature cycles. The high and low points in the cycles differed, depending on shift worked and days off, and a pattern of problems emerged that was related to rotating work schedules. Solving these problems required a compromise of individual preference, operational requirements, costs, and circadian principles.
Comparing Plant‐Scale Dual‐ and Mixed‐Media Filters
Authors: Barnett Elliott , Robinson R. Bruce , Loveday D. Wayne , Snyder Joe
Published: February 2018

Full‐scale dual‐ and mixed‐media filters were compared side by side at nominal loadings of 3, 4, 5, and 6 gpm/sq ft for eight months using flocculation and sedimentation pretreatment. Both media produced an effluent of <0.5 ntu at all loadings. The mixed‐media filter was more successful than the dual‐media filter for attaining a potential 0.1 ntu effluent standard using the plant's current pretreatment. The media performed equally in removing residual aluminum and would require about the same initial filter to waste, roughly 0.5 percent of the run. Neither media showed turbidity breakthrough when subjected to a 33 percent flow surge or showed significant media loss. The mixed media showed slightly higher energy costs, which were not considered significant. For replacing media in the eight remaining filters, the mixed media was estimated to cost $48,000 more for the media itself and installation and to cost between $4,000 and $17,000/year more for backwash water.
Tastes and Odors Associated With Chlorine Dioxide
Authors: Dietrich Andrea M. , Orr Margaret P. , Gallagher Daniel L. , Hoehn Robert C.
Published: February 2018

A survey was conducted to determine practices and problems associated with the use of chlorine dioxide (ClO2) by US water utilities. The survey acquired data concerning raw‐ and finished‐water quality as well as treatment processes. A specific emphasis of the survey was to investigate the association of adverse odors (particularly those resembling kerosene and cat urine) with ClO2 application. The results indicate that ClO2 is primarily applied to reduce the formation of trihalomethanes. Offensive odors associated with the application of ClO2 were not correlated with raw‐ or finished‐water quality. Odors were more intense and more diverse when ClO2 was used, and increased numbers of complaints about odors were associated with the presence of new carpets in customers' homes.
Comparing Chlorination and Chloramination for Controlling Bacterial Regrowth
Authors: Neden Douglas G. , Jones Robert J. , Smith Judy R. , Kirmeyer Gregory J. , Foust Glenn W.
Published: February 2018

The Greater Vancouver (B.C.) Water District compared chlorine and chloramine as secondary disinfectants and their effects on bacterial regrowth in a distribution system supplied with disinfected, unfiltered surface water. The selected section of the distribution system was divided into three areas: a control area that received no secondary disinfectant, an area that received free chlorine as the secondary disinfectant, and an area that received chloramine. Water samples were analyzed for chlorine residual, coliform bacteria, heterotrophic plate count (HPC) bacteria, and turbidity. Although both chlorine and chloramine were effective in reducing bacterial growth in the distribution system, chloraminated water had a lower HPC, less taste and odor, fewer positive coliforms, and a more stable residual.
Evaluating a New Granular Iron Oxide for Removing Lead From Drinking Water
Authors: Theis Thomas L. , Iyer Ramesh , Ellis Sonia K.
Published: February 2018

A granular adsorbent consisting of iron oxide particles cemented by a binding material was investigated for its ability to remove lead ion from water using both batch and column experimental methods. Results showed the optimum pH for removal to be between 5 and 7. Roth batch and column studies yielded similar values for the binding constant—about 5—but column studies indicated a significantly larger capacity, with a value of 4.3 mg Pb/g of adsorbent. Regeneration of the sorbent can be achieved by flushing with an acidic solution (pH = 3), although for long adsorption runs some buildup of residual lead within the pores is possible as a result of incomplete desorption.
Integrated Pilot Testing Pays Off
Authors: Hubel Richard E. , Howe Elaine W. , Wilczak Andrzej , Wolfe Timothy A. , Tambini Steven J.
Published: February 2018

A pilot study was undertaken for a regional water supply project to develop cost‐effective water treatment plant design criteria, ensure compliance with drinking water regulations, produce water that would taste good to potential customers and incorporate processes that protect the water supply from contamination. An integrated pilot testing program allowed for the study of the multiple variables inherent to surface water treatment. The results were used to develop optimal process design criteria that correlate with full‐scale plant construction cost savings. In addition, the pilot study revealed ozonation's beneficial effect on the removal of particles, the operational flexibility of the selected process during sudden changes in raw water turbidity and flow rate, and the capability of the selected process to remove synthetic organic chemicals that may reach the intake.
Effect of Calcium on Thermal Regeneration of GAC
Authors: Knappe Detlef R. U. , Dagois Gérard , DeWolfe James R.
Published: February 2018

Calcium commonly accumulates on granular activated carbon (GAC), and when it is chelated by natural organic matter (NOM), it is drawn into the pores of the GAC. Internally loaded calcium greatly catalyzes regeneration reactions, leading to accelerated internal mass loss. Optimal conditions for the regeneration of a GAC not loaded with calcium lead to severe overregeneration if applied to a calcium‐loaded GAC. The pore structure and capacity of the GAC are adversely affected by this overregeneration. The authors of this article found that calcium‐loaded GACs could be regenerated to yield a GAC with the properties of the virgin GAC by reducing the regeneration time or temperature.
Cucumber Flavor in Philadelphia's Drinking Water
Authors: Burlingame Gary A. , Muldowney John J. , Maddrey Roy E.
Published: February 2018

Since 1981, when the use of free chlorine was curtailed to control trihalomethanes at the Baxter Treatment Plant in Philadelphia, Pa., a seasonal cucumber flavor problem occurred. Flavor profile analysis was the only tool available to guide treatment. During 1990, the cucumber odor was tracked more than 250 mi (402 km) up the Delaware River to the Cannonsville Reservoir, and the odor‐causing compound was identified as trans,2‐cis, 6‐nonadienal. Algae growth beneath the winter ice produced the compound. Other treatment plants on the river that used free chlorine for disinfection and a final residual never had a problem with trans,2‐cis,6‐nonadienal. Therefore, use of chlorine was increased at the Baxter plant to control the cucumber flavor. Studies were conducted on trans,2‐cis, 6‐nonadienal to describe its sensory characteristics and analytical detection limit.
What Will Water Rates Be Like in the 1990s?
Authors: Russell David F. , Woodcock Christopher P. N.
Published: February 2018

The prices many municipal suppliers and private water utilities charge for water have increased dramatically over the past decade; in some cases they have doubled or tripled. For example, in 1980 a major water authority in the Northeast was charging $1.0l/l,000 gal. The comparable rate today is $2.05. In a large southwestern community, rates during the six warmest months increased from $0.74 to $2.07 per 1,000 gal in the 1980s. Overall charges for water service increased at an average compound rate of about 7 percent per year during the last decade. Many factors led to these increases, including general inflation, higher capital costs, and more stringent environmental regulations. When amendments to the Safe Drinking Water Act are fully implemented and as pressure increases to preserve and protect the nation's water resources, it is reasonable to expect that price increases will follow this trend and may surpass it during the 1990s. These increases will strongly influence the use and management of this valuable resource. In addition to continued dramatic overall rate increases, the 1990s will be characterized by increasing block rates, other conservation‐based charges, and more widespread adoption of impact fees. This article concludes with some insights into the effects of such changes on the water industry and its customers.
Use of EJCDC Documents Reduces Conflicts
Authors: Henderson Kenneth W.
Published: February 2018

It is important to the efficient progress of a construction project that disputes among the parties be resolved efficiently. Standard contract documents available from and periodically updated by the Engineers Joint Contracts Document Committee are a convenient and economical vehicle for ensuring that conflict at any time during a project is minimized. The documents' standard language has become well known to bidding contractors and the legal profession, resulting in more competitive bidding and less frequent litigation.
Assessing Sulfur Turbidity Formation Following Chlorination of Hydrogen Sulfide in Groundwater
Authors: Lyn Troy L. , Taylor James S.
Published: February 2018

This article describes the effects of sulfide concentration, chlorine‐to‐sullide molar ratio, reaction pH, dissolved oxygen, and reaction time on sulfide destruction and sulfur turbidity formation following chlorination of hydrogen sulfide. Sulfur turbidity was formed at all reaction pH values >3.8. It was stable and could not be removed by sedimentation, increased chlorine dosage, or increased reaction time. A major conclusion of this work is that elemental sulfur is being discharged to potable water distribution systems by thousands of US water treatment plants that do not remove sulfur turbidity following hydrogen sulfide chlorination.
Using Isotherms to Predict GAC's Capacity for Synthetic Organics
Authors: Qi S. , Snoeyink Vernon L. , Beck E.A. , Koffskey Wayne E. , Lykins Benjamin W.
Published: February 2018

This investigation involved operating a pilot granular activated carbon (GAC) plant to obtain capacity data under typical field conditions, determining isotherms for selected synthetic organic chemicals, and comparing the capacity predicted by the isotherm data with the pilot‐plant capacity data. The pilot‐plant GAC capacities at saturation for empty bed contact times of 2.5 to 5.0 min were within a factor of 2.5 of the isotherm capacities. This is reasonably good agreement, considering that the displacement effects that take place in the GAC columns are not accounted for in the isotherm calculations.
Evaluating the Formation of Brominated DBPs During Ozonation
Authors: Glaze William H. , Weinberg Howard S. , Cavanagh Joseph E.
Published: February 2018

Ozonation of natural waters containing bromide ion leads to the formation of inorganic hypobromite and bromate and many brominated organic by‐products, only a few of which have been identified. The study described here identified bromoform, bromoacetonitriles, bromoacetone, bromoacetic acids, and a group of labile compounds referred to as bromohydrins. These by‐products are reactive toward most quenching agents used for their stabilization. Dissolved organic bromide (DOBr) formation was favored by a low pH, low alkalinity, and low ammonia concentration and increased as a function of bromide concentration in the raw water. A mass balance of bromide indicates that, in some cases, <10 percent of the DOBr content has been identified.
SDWA: A Look Back
Authors: Pontius Frederick W.
Published: February 2018

Drinking water has been the subject of laws and regulations in the United States for nearly 100 years. The roots of the Safe Drinking Water Act (SDWA) and its evolution over the years testify to the desire for and challenge of ensuring safe drinking water. This paper presents a historical review of the first drinking water law set in 1893, federal standards issued in 1914, the passage of the Safe Drinking Water Act in 1974, and the 1986 and 1988 amendments.
Determining Health Risks Associated With Disinfectants and Disinfection By‐products: Research Needs
Authors: Glaze William H. , Andelman Julian B. , Bull Richard J. , Conolly Rory B. , Hertz Charles D. , Hood Ronald D. , Pegram Rex A.
Published: February 2018

In order to minimize the levels of potentially toxic disinfectants and disinfection by‐products in treated water while maintaining adequate protection against microbiological contamination, the total risks associated with disinfection have to be measured and compared with the risks from microbial agents. Because much work has already been carried out on chlorination and its by‐products, it is recommended that research focus on major disinfection alternatives, i.e., ozonation, chloramination, carbon dioxidation, and the most practical combinations of these options. The primary research needs are (1) assessment of the relative toxicological hazards of the disinfectants and their by‐products and (2) development of biologically based models for the dose–response relationships of these chemicals.
Chemicals Versus Microbials in Drinking Water: A Decision Sciences Perspective
Authors: Putnam Susan W. , Graham John D.
Published: February 2018

Public health interventions aimed at reducing one risk may actually increase another risk. For example, concern is growing about the chronic health risks associated with the chemical agents used by many water systems to protect against waterborne microbial disease. Some combination of microbial and chemical risks appears to be unavoidable. Science alone cannot resolve this dilemma, because a value judgment that is sensitive to citizens' attitudes toward risk must be made. To compare health risks, the ultimate health effects need to be expressed in the same unit of measurement. Using an analytical framework called decision analysis, policymakers can analyze risks and attitudes in terms of public health effects, economic cost to society, and consequences for overall quality of life. In the current disinfection regulatory deliberations, the US Environmental Protection Agency (USEPA) is approaching the issue from an economic standpoint, whereas if it were to analyze the issue from a different angle, the relative attractiveness of the regulatory scenarios might be quite different. USEPA's current struggle to weigh the trade‐offs involved in setting regulations for disinfectants and their by‐products underscores the need for targeted social science research about attitudes toward risk.