bluuebunny/crossref_metadata_2025 huggingface dataset:
Ozone Use in Denmark
Authors: Beck Jørgen
Published: February 2018

The author of this letter discusses the use of ozone as a primary disinfectant with postdisinfection achieved through the use of preformed monochloramine. The preformation of a strong stock solution of monochloramine under optimum conditions gives a chemically well defined solution of pure monochloramine and no detectable amounts of free chlorine, dichloramine, or trichloramine, which are responsible for tastes and odors. Since the introduction of the use of preformed monochloramine there has been an improvement in taste and odor and no trihalomethanes have been found in the water.
The Stability of Turbidity in Raw Water and Its Relationship to Chlorine Demand
Authors: Katz Edward L.
Published: February 2018

In this study, 160 raw water samples collected throughout the United States were examined for chlorine demand, turbidity, and other chemical parameters to determine whether these parameters were interrelated. After raw water samples were examined, they were filtered through 0.45‐μm membrane filters, and the filtrate and residue were then analyzed. Other parameters such as total organic carbon, total Kjeldahl nitrogen, volatiles, suspended solids, particle size, and inorganics were also examined. Eighty‐nine of these samples were also examined over a one‐week period to determine the stability of the turbidity values over one, three, and seven days. Changes in turbidity were on the order of 77 percent of samples in the range of 0.05–1 ntu, 90 percent of samples in the 1‐5 ntu range, and 96 percent of those >;5.0 ntu. In some cases, more than a 200‐percent change in turbidity is reflected. In 63 percent of the samples, changes of 10–50 percent were seen. Because of this strong indication of inherent instability of turbid raw water samples, measurements of samples should be done immediately on site to ensure accuracy of turbidity readings.
A Case Study of Geosmin in Philadelphia's Water
Authors: Burlingame Gary A. , Dann Roger M. , Brock Geoffrey L.
Published: February 2018

Two episodes of unacceptable tastes and odors, which corresponded with levels of geosmin in the water that were much higher than the background level of 20 ng/L or less, occurred in Philadelphia during 1985. The source of one episode was found to be a localized bed of algae in the Schuylkill River. An existing taste‐ and odor‐control program, which utilizes instrumental and sensory analyses, was largely responsible for the effective management of the episodes. Hydraulic strategies were used to reduce the treatment plant's intake of geosmin, and powdered activated carbon in the treatment train further reduced the geosmin level. Dilution of this treated water with other finished waters in the distribution system also diminished the impact of geosmin on the taste and odor of Philadelphia's water.
An Early Warning System for Taste and Odor Control
Authors: Means Edward G. , McGuire Michael J.
Published: February 2018

In 1979 an annual cycle of taste and odor episodes began in Lake Mathews, a storage reservoir that is part of The Metropolitan Water District of Southern California. In order to set up an early warning system that would detect impending taste and odor episodes, the utility developed a methodology for identifying the earthy‐musty odors that plagued the reservoir, identified the agents causing the problems, studied the agents' habitat and distribution in the reservoir, and explored the various treatment methods available for controlling the agents. Advance notice has effectively been provided by the early warning system, which includes regular sampling of the reservoir in seven preselected locations. With this system, the utility has been able to minimize the severity and extent of annual taste and odor episodes. Thus far, application of chunk copper sulfate has proved to be most economical, but some concern exists that the algae may develop a resistance to the treatment.
Water Rates: An Industrial User's View
Authors: Harwig Ernest , Smith Ronald A.
Published: February 2018

What criteria for developing water rates are used by large industry? General Motors negotiates contracts with water utilities based on fairness to both the corporation and the water utility. Water revenues, in the view of GM, should be reasonable and adequate to maintain the financial and operational stability of the water utility. Charges should be based on selfsupporting, cost‐of‐service rates with little customer cross‐subsidization and minimal revenue subsidization from other sources, such as taxes. Written service contracts are suggested as an appropriate tool to achieve these goals.
Influence of pH on the Removal of Organics by Granular Activated Carbon
Authors: Semmens Michael J. , Norgaard Gregor E. , Hohenstein Gary , Staples Alan B.
Published: February 2018

Studies with miniature columns of granular activated carbon (GAC) demonstrated the importance of pH in the removal of total organic carbon and trihalomethane precursors from coagulated Mississippi River water.
Viewpoint – Turning Problems Into Advantages
Authors: Richardson William H.
Published: February 2018

This article is an adaptation of an address to the 1985 Kentucky‐Tennessee section meeting held in Lexington, Ky., Nov. 4, 1985. William H. Richardson is a partner with Alvord, Burdick, and Howson, consulting engineers of Chicago, Ill., and a past‐president of AWWA.
Computer‐Controlled Groundwater Management in Zurich
Authors: Schalekamp Maarten
Published: February 2018

Computer control of the Hardhof groundwater plant is necessary to adhere to operational criteria stipulated by the canton of Zurich. Drawdown cannot exceed the licensed levels of the wells, and to maintain water quality, recharge of the wells from the Limmat River must be balanced against streamflow and the direction of runoff within the wellhead protection zones. The computer installation at Hardhof also assists with managing energy costs for the city's water supply and security systems for the physical plants.
Honolulu's New SCADA System
Authors: Wada Ronald N. , Chan Edward H. P. , Hayashida Kazu
Published: February 2018

A new computer‐based supervisory control and data acquisition (SCADA) system controls and monitors the Honolulu Board of Water Supply's pumping, storage, and distribution operations. Two operator consoles with color CRTs display water system data in symbol form and in trend format and also control pumps and valves at remote stations. In addition, the system automatically generates reports from the data it collects. Software is currently being developed that will reduce electrical power costs by time‐controlling pumps to take advantage of off‐peak rate schedules.
Nitrification and Nitrosation on the Surface of GAC
Authors: DiGiano Francis A. , Carrier Richard A. , Dietrich Andrea M.
Published: February 2018

The attached‐growth nitrification process was investigated to determine whether it can induce nitrosamine formation when the precursor secondary amine is adsorbed on the surface of activated carbon and the ammonia concentration is fairly low (2 mg NH4‐N/L). Most reports of nitrification concern wastewater treatment, in which concentrations of ammonia are much higher than in raw water supplies. The lower the ammonia concentration, the lower the concentration of nitrite (the intermediate product), and the less likely is reaction with sorbed secondary amine to form N‐nitrosamine.
Responding to Industrial Contamination of Groundwater: A Case Study
Authors: Dever Raymond J.
Published: February 2018

The case study presented describes the discovery and the investigation of the trichloroethylene and related contamination of a public noncommunity well water supply in Montgomery County, Md. Although the local government's response to this potential public health threat was eventually successful, the government encountered several serious technical, legal, and institutional obstacles. Conclusions are drawn from this experience and recommendations are given to provide guidance to other utilities and public health agencies that may be faced with similar problems in the future.
Design and Evaluation of an Air‐Stripping Tower for Removing VOCs From Groundwater
Authors: Hand David W. , Crittenden John C. , Gehin Joseph L. , Lykins Benjamin W.
Published: February 2018

An air‐stripping tower was designed to treat 1500 gpm (0.09464 m3/s) of groundwater contaminated with trichloroethene, tetrachloroethene, cis‐1, 2‐dichloroethene, toluene, ethyl benzene, and isomers of xylene. A simplified procedure for designing a tower with the smallest volume and energy requirements was used. Data for the first four months of operation demonstrated excellent removals for the six volatile organic compounds. The cost of treatment was about $0.0586/1000 gal (3.785 m3) of water treated. Operating problems, microbiological analyses, and data regarding total organic halogen (TOX) and TOX formation potential are summarized.
Weak‐Acid Ion Exchange for Removing Barium, Radium, and Hardness
Authors: Snyder David W. , Snoeyink Vernon L. , Pfeffer Julie L.
Published: February 2018

Weak‐acid resin in the hydrogen form was found to effectively remove barium, radium, and hardness, without increasing the sodium content of the product water. The maximum capacity of the weak‐acid resin was about 2.3 times that of strong‐acid resin, and much less spent regenerant per unit volume of water treated was produced from a weak‐acid column than from a strong‐acid column. There are, however, some disadvantages to weak‐acid ion exchange swelling of the resin during exhaustion, the need to use acid‐resistant materials, the inability to remove noncarbonate hardness, the necessity of stripping carbon dioxide from the product water and adjusting the pH, and the probable higher cost.
Restoring the Flow of a Finished Water Pipeline
Authors: Fitch David E. , McCollum Gary R.
Published: February 2018

Large doses of alum used for flocculation by the Onondaga County (N.Y.) Water Board caused a buildup of aluminum and silicone oxides on the interior of large distribution pipes. Flow was restricted to the point that supplying demand during peak usage might have become a problem. Planning for a pigging operation was begun in 1983, and the job was successfully undertaken on the Memorial Day weekend of the following year without disrupting production of a major industrial user. The authors describe how the pigging operation was done and the improvement that resulted.
Comparing Gel Permeation Chromatography and Ultrafiltration for the Molecular Weight Characterization of Aquatic Organic Matter
Authors: Amy Gary L. , Collins Michael R. , Kuo C. James , King Paul H.
Published: February 2018

Gel permeation chromatography (GPC) and ultrafiltration (UF), both relatively inexpensive analytical techniques requiring moderate levels of analyst expertise, are potential tools for monitoring the presence of aquatic organic matter and humic substances in raw water sources as well as the removal of organic constituents during water treatment. The two methods provided somewhat different trends in the relative molecular weight distribution of dissolved organic matter in various water sources. The GPC method generally indicated a higher molecular weight than the UF method for a given source. Moreover, the GPC method was found to be more significantly affected by pH conditions.
Developing Haloform Formation Potential Tests
Authors: Batchelor Bill , Fusilier David , Murray Edward H.
Published: February 2018

There is a need for accurate, rapid, and easily measured surrogate parameters for trihalomethane formation potential (THMFP) to aid in the control of water treatment plants. Four haloform formation potential (HFP) tests have been developed to meet this need. They are based on replacing chlorine in the THMFP test with iodine or bromine. The iodoform or bromoform produced by reaction with natural organic matter can be measured with a spectrophotometer rather than a gas chromatograph. Kinetics of formation of iodoform and bromoform were studied at 25, 50, and 100°C using solutions of commercial humic acid. Correlation experiments showed that the HFP tests were better able to predict THMFP than conventional surrogate parameters, total organic carbon and ultraviolet absorption. On the basis of ease of analysis, analysis time, and ability to predict THMFP, the HFP tests appear to be improved surrogate parameters for THMFP.
Corrosion Monitoring and Control in the Pacific Northwest
Authors: Reiber Steve H. , Ferguson John F. , Benjamin Mark M.
Published: February 2018

An 18‐month monitoring program evaluated the relationship between copper plumbing corrosion and variations in delivered water quality in several communities in the Pacific Northwest. Significant relationships were found for copper corrosion rate dependence on pH and free chlorine residual. Regression analysis provided a statistical means of identifying the important predictors of copper corrosion rates in low mineral waters.
A Tale of 26 Million Good Intentions
Authors: Miller B.J.
Published: February 2018

A fanciful tale of California's water history is presented.
Using Asiatic Clams as a Biomonitor for Chrysotile Asbestos in Public Water Supplies
Authors: Belanger Scott E. , Cherry Donald S. , Cairns John , McGuire Michael J.
Published: February 2018

Comparisons of Asiatic clams (Corbiculasp.) exposed to chrysotile asbestos in the laboratory and the field were undertaken in 1983 and 1984 to evaluate the usefulness of 30‐day laboratory exposures for predicting the accumulation of chrysotile by clams in the field. Clams exposed in the laboratory accumulated fibers that were shorter and had greater aspect ratios (length to width) than those found in water. In the field, fibers in clam tissues were approximately the same size as those found environmentally. Bioconcentration factors (BCFs) for asbestos were low in the laboratory (slightly greater than 1). In the field, however, viscera BCFs were as high as 100, and whole clam homogenates ranged from 1400 to 5000. These data are consistent with the theory that asbestos fibers are difficult to depurate.Corbiculais a good candidate for use as a biomonitor for chrysotile asbestos contamination.
Oregon's Response to Chernobyl Fallout
Authors: Paris Ray D.
Published: February 2018

This article discusses the response of the Oregon Health Division to the Chernobyl nuclear accident in the Soviet Union. The health department concentrated on three areas: the public was informed of the day‐to‐day changes in radioactivity levels; the public health significance of radioactivity levels found in exposure pathways was explained in basic concepts; and a telephone hot line was established to address the questions of concerned citizens immediately.
The Transfer of Radon From Domestic Water to Indoor Air
Authors: Prichard Howard M.
Published: February 2018

Theoretical and experimental literature dealing with the release of radon from water to air is reviewed and synthesized. Primary emphasis is placed on releases from domestic water supplies to indoor air within the context of a general indoor radon problem. The widely used assumption of 1 pCi/L increment in indoor air per 10 000 pCi/L in the water supply is valid, but regional and individual variations are important.
Committee Report: Microbiological Considerations for Drinking Water Regulation Revisions
Authors:   AWWA Organisms in Water Committee
Published: February 2018

Because of the importance of the microbiological quality of water, the AWWA Organisms in Water Committee elected to review the various options and approaches that had been proposed in connection with revised drinking water regulations. This report addresses these proposals, as well as current practice, and summarizes the committee's concerns and recommendations.
High‐Efficiency Motors
Authors: Jeptha A. Wade , Rossi Michael J. , Guzzetta Robert R.
Published: February 2018

The replacement of older models of pump motors with new, high‐efficiency motors can be an effective means of conserving both energy and capital. To promote this method of conservation, in 1983 the Pacific Gas and Electric Company (PG&E) initiated a rebate program to encourage its water utility customers to install high‐efficiency motors wherever possible. However, as the California Water Service Company (CWSC) found, rigorous analyses must be undertaken to determine whether the cost benefits of replacing older motors outweigh those of simply repairing them. In addition, utilities must be familiar with motor design, types of energy losses encountered in most motors, standards for testing motors’ levels of operating efficiencies, and means of enhancing motor efficiency if they are to ensure the highest level of motor productivity for the lowest energy and capital costs.
Data Bases: Getting the Most for Your Money
Authors: Chow Bruce M.
Published: February 2018

This article addresses the usefulness and the need for properly designed water quality data bases. Data bases are defined, and examples of their applications in the water industry are given. Also, basic design principles for incorporating some of the unique requirements for water quality data contained in data bases are highlighted. Because the principles apply to any of the data base languages, the discussion has been generalized to exclude references to specific software packages as much as possible.
Effects of Storage and Preoxidation on Sludge and Water Quality
Authors: Hoehn Robert C. , Novak John T. , Cumbie William E.
Published: February 2018

Ever since the city of Newport News, Va., eliminated prechlorination at its water treatment facilities in 1982 in order to control trihalomethanes, it has been plagued by deterioration of alum sludges in manually cleaned sedimentation basins and by occasional declines in settled water quality. Laboratory and field studies showed that anaerobic conditions develop rapidly in manually cleaned sedimentation basins (but not in those that are mechanically cleaned), allowing manganese to be released from the sludge into the overlying water. The use of chlorine dioxide as a preoxidant was found to suppress this release of manganese, produce sludges with improved dewatering characteristics, and lengthen filter runs.
Reservoir Management
Authors: Meadows Michael D.
Published: February 2018

This article recounts the successful strategies implemented by the city of Waco, Texas, to improve the quality of its raw water reservoir. The control of taste‐ and odor‐causing blue‐green algae was a recurring problem until the water utility began to inject compressed air into the reservoir to cause destratification. This practice has successfully controlled the growth of algae, thereby simplifying treatment processes. Watershed management in combination with routine sampling and analyses further protects the quality of the raw water that serves the city.
Removing Arsenic From Drinking Water
Authors: Hathaway (deceased) Steven W. , Rubel Frederick
Published: February 2018

Pilot‐plant tests of two treatment methods—activated alumina and ion exchange—for removing arsenic from drinking water were evaluated at the Fallon, Nev., Naval Air Station (NAS). The arsenic concentration was 0.080‐0.116 mg/L, exceeding the 0.05‐mg/L maximum contaminant level. Although the valence of arsenic was not determined, the prechlorination process and test results suggest it was probably arsenic V. Chlorinated drinking water from the NAS was used for evaluating the efficacy of treatment under several different conditions. The activated alumina and ion exchange systems were operated through three different loading and regeneration cycles each. The major water quality factors affecting the removal of arsenic by these methods were: pH of feedwater, arsenic concentration, sulfate concentration, and alkalinity. The major operational factors affecting removal were: flow rate, down time, and media clogging. Capital and operating costs for arsenic removal are estimated for the activated alumina method at optimum pH (5.5) for each of the three small community systems drawing water from the same aquifer. In addition, several containers of the regeneration waste were used for a special study to characterize, dewater, and render the waste nontoxic for disposal in a sanitary landfill.
Strong‐Acid Ion Exchange for Removing Barium, Radium, and Hardness
Authors: Snoeyink Vernon L. , Cairns‐Chambers Carl , Pfeffer Julie L.
Published: February 2018

The research discussed in this article was conducted to investigate and document the performance of conventional sodium‐form strong‐acid resins for the combined removal of barium, radium, and hardness under controlled conditions. The reasons for the study were: (1) the premature leakage of barium from strong‐acid ion exchange columns, (2) a lack of controlled laboratory studies to determine the factors affecting resin performance, and (3) a lack of documentation regarding the effect of the quantity of regenerant applied on effluent quality and on effluent quality as a function of the amount of water processed during a run.
Committee Report: Research Needs for the Treatment of Iron and Manganese
Authors:   Trace Inorganic Substances Committee
Published: February 2018

Iron and manganese problems affect far more water systems than almost any other water quality concern. The committee that prepared this report believes there is still much to learn about the chemistry, treatment, and control of iron and manganese and that there is considerable room to improve treatment effectiveness while reducing treatment costs. Such goals are especially relevant to small water systems, which are frequently afflicted with iron and manganese problems.
The Treatability of Manganese by Sodium Silicate and Chlorine
Authors: Robinson R. Bruce , Ronk Susan K.
Published: February 2018

Manganese sequestering by nearly simultaneous additions of sodium silicate and sodium hypochlorite was studied in laboratory‐prepared waters. Under conditions of near‐neutral pH and 150–250 mg/L of alkalinity as CaCO3, 1–2 mg manganese/L could be sequestered for up to one day. Less effective manganese treatability was found at pH 8 than at pH 7. Additionally, at pH 7 the best results were obtained when neither silicate nor hypochlorite was added because of the slow manganese oxidation rate by oxygen alone. Aging of diluted stock silicate solutions prior to dosing also gave poor treatment; the presence of background silica increased the treatment effectiveness only slightly. Overall, manganese was less treatable by this method than iron under the same treatment conditions.
Evaluating Alternative Coagulants to Determine Efficiency and Cost Effectiveness
Authors: McKeon William R. , Muldowney John J.
Published: February 2018

Ferrous sulfate was studied as an alternative coagulant to ferric chloride. Coagulants were evaluated for iron content, heavy metal contaminants, acidity, chlorine demand, and settleable solids. Jar tests and split‐plant trials demonstrated similar performance at comparable costs with either coagulant. An anomaly that was evident throughout the study was that a pound of iron in the form of ferrous sulfate was 20 percent more effective than iron as ferric chloride. An equation was developed to compare ferric chloride and ferrous sulfate on a cost and performance basis for subsequent bids. As a result of the increased competition in bidding, there was a 50 percent decrease in the cost of coagulant over a three‐year period.
Schmutzdecke Characterization of Clinoptilolite‐Amended Slow Sand Filtration
Authors: McNair Daniel R. , Sims Ronald C. , Sorensen Darwin L. , Hulbert Matthew
Published: February 2018

Studies were conducted to characterize the growth and composition of the schmutzdecke and the associated particle removal efficiency for a field‐scale experimental slow sand filtration (SSF) system used for the biological treatment of Logan River water. A naturally occurring ammonium‐selective zeolite, clinoptilolite, was added as a surface amendment to the sand bed of the SSF system as a reservoir of nitrogen for algae comprising the schmutzdecke. A predominance of filamentous algae at the surface of the filter was observed throughout the entire experimental period. Single‐cell algae were observed at depths in the filter from 0.5 to 1 in. (15 to 30 mm). Particle removal was superior in clinoptilolite‐amended SSF, even at filtration rates two to four times greater than conventional SSF rates. The effect of schmutzdecke maturation on the removal of Giardia lamblia cyst‐size particles was also investigated. The growth of algae following the initiation of a filtration cycle, i.e., the maturation period of the schmutzdecke, was associated with an increase in the ability of the amended filter to remove Giardia lamblia cyst‐size particles. The zeolite‐amended SSF system treated drinking water for longer periods of time at higher filtration rates than achievable with conventional SSF without the zeolite surface amendment.
SDWA Amendments: Effects on the Water Industiy
Authors: Dyksen John E. , Hiltebrand David J. , Raczko Robert F.
Published: February 2018

Water utilities throughout the United States will be affected by the 1986 amendments to the Safe Drinking Water Act. The authors describe these effects along with suggesting preparations that can be undertaken to meet the requirements of the new law when it is fully implemented. Water utilities must deal with new contaminant standards, including installation of new treatment technologies that may be needed to meet these new standards. Wellhead protection programs and required disinfection of groundwater and surface water supplies will change the way in which many systems now operate. The far‐reaching effects of more stringent regulation of the by‐products of disinfection, coupled with disinfection adequate to contend with viruses and Giardia, will cause an exquisite balancing of potentially conflicting goals in water treatment.
Assessing Unfiltered Water Supplies
Authors: Leland David E. , Berg Paul A.
Published: February 2018

Statutory provisions under the 1986 amendments to the Safe Drinking Water Act require water utilities using unfiltered surface sources to disinfect and filter or to meet stringent criteria for remaining unfiltered. Three unfiltered surface water systems in Oregon were evaluated in two areas: (1) their ability to meet the criteria for remaining unfiltered and (2) the steps they must take to document the shortcomings of their systems and to accumulate the data they will need to prove the safety of their unfiltered supplies. These examples and the accompanying bibliography that addresses the problems of meeting the new standards for unfiltered surface supplies can help utilities prepare for final implementation of the surface water treatment rule.
Implementing a Lead Solder Ban
Authors: Glicker Joe , Stewart Don
Published: February 2018

One of the most significant aspects of the 1986 Safe Drinking Water Act amendments is the ban on the use of lead solder and lead pipes, which is similar to a ban enacted by the state of Oregon in 1984. Implementing such a ban requires a close coordination among the water utility, plumbing inspectors, plumbing code authorities, and health officials. Education and enforcement programs are essential to ensure that the ban is effective. Understanding the experiences in establishing the ban in Oregon and enforcing it in Portland may be useful as the lead ban is extended nationwide.
International Standards for Drinking Water
Authors: Sayre Ida M.
Published: February 2018

Official and semi‐official drinking water standards have been adopted by most of the industrialized nations in North America and Europe. The majority of drinking water professionals in Europe and North America agree that legally enforceable standards are necessary to ensure public health. Biologically safe water is the first priority, but now that this has, for the most part, been achieved, attention is being turned to inorganic contaminants and the pervasive organic contaminants that challenge water treatment technologies and analytical capabilities. This article compares the regulations, standards, and guidelines used in the United States, Europe, and Canada and those suggested by the World Health Organization.
AWWARF Trihalomethane Survey
Authors: McGuire Michael J. , Meadow Robert G.
Published: February 2018

This survey was conducted to determine the extent and costs of compliance with the existing maximum contaminant level (MCL) for trihalomethanes (THMs). It was found, on average, that the MCL of 0.10 mg/L had reduced the concentrations of THMs in larger utility systems by 40–50 percent. About 4.6 percent of the responding utilities had exceeded the MCL at least once during the period 1984–86. Compliance with the THM regulation involved estimated capital expenditures of $31–102 million and yearly operating and maintenance costs of $8–29 million for utilities serving more than 10,000 people. Approximately 75 percent of the water quality managers responding believed that the MCL should not be reduced below 0.10 mg/L. Only four states require that smaller utilities (those serving fewer than 10,000 people) monitor for THMs.
Selecting Optimal Pipe Sizes for Water Distribution Systems
Authors: Walski Thomas M. , Gessler Johannes , Sjostrom John W.
Published: February 2018

In spite of the fact that computers are taking over increasing amounts of the engineer's computational work, selecting pipe sizes for water distribution systems remains a process based on rules of thumb and trial and error. Computerized procedures for sizing distribution system pipe are becoming available, but acceptance is limited because few optimization models are available as user‐friendly tools that can be easily applied by engineers. This article describes a computer program developed by the authors that follows the conventional trial‐and‐error approach to pipe sizing.
Optimizing the Removal of Geosmin and 2‐Methylisoborneol by Powdered Activated Carbon
Authors: Lalezary‐Craig Shala , Pirbazari Massoud , Dale Melissa S. , Tanaka Theodore S. , McGuire Michael J.
Published: February 2018

The purpose of this study was to determine the conditions under which removal of the taste‐ and odor‐causing compounds geosmin and 2‐methylisoborneol (MIB) by powdered activated carbon (PAC) was most efficient. It was observed that a PAC dosage as low as 5 mg/L could reduce commonly occurring concentrations of these organics (up to 20 ng/L) to acceptable levels. Chlorine and monochloramine residuals appeared to have an adverse effect on the adsorption of geosmin and MIB by PAC, as did the presence of background humic acid. Filtration rate and contact time did not significantly affect removal efficiency.
Advanced Oxidation Processes for Treating Groundwater Contaminated With TCE and PCE: Pilot‐Scale Evaluations
Authors: Aieta E. Marco , Reagan Kevin M. , Lang John S. , McReynolds Laurent , Kang Joon‐Wun , Glaze William H.
Published: February 2018

This article presents the results of a pilot‐scale evaluation of an advanced oxidation process that utilizes hydrogen peroxide and ozone. Treatment efficiency was determined as a function of the hydrogen peroxide‐to‐ozone dosage ratio, ozone dosage, and contact time. The ozone mass transfer characteristics of the process were also investigated. Comparison with other treatment technologies indicates that advanced oxidation can be a cost‐effective treatment process for controlling the common chlorinated organics found in groundwater.
Using GAC to Remove VOCs From Air Stripper Off‐Gas
Authors: Crittenden John C. , Cortright Randy D. , Rick Brad , Tang Shin‐Ru , Perram David
Published: February 2018

This article focuses on the technical and economic feasibility of treating air stripper off‐gas with granular activated carbon (GAC). For dichloroethene and trichloroethene, air stripping followed by off‐gas GAC treatment was shown to be very effective and economical compared with aqueous‐phase GAC treatment, with GAC usage rates for gas‐phase adsorption being less than one half those for aqueous‐phase adsorption. Also, because gas‐phase adsorption kinetics are much faster than liquid‐phase kinetics, the required bed depth and diameter are much smaller for gas‐phase beds. Steam regeneration was found to be ineffective for regeneration gas‐phase GAC at low concentrations.
Growth Kinetics of Hydroxide Flocs
Authors: François R.J.
Published: February 2018

This article describes how mathematical expressions of the kinetics of flocculation are applied when a hydrolyzing metal salt is used as the coagulant. It includes not only an evaluation of the phenomena observed but also substantial experimental data.
Radionuclides in Drinking Water
Authors: Lowry Jerry D. , Lowry Sylvia B.
Published: February 2018

Impending new maximum contaminant levels (MCLs) for radionuclides, plus increased concern for radon in the air inside homes, have sparked new interest in these substances. An assessment of research needs,∗ which also provided background information on completed and ongoing research projects, showed that Rn‐222 represents the most serious threat to health of all the radionuclides in drinking water, leading to the anticipation that the new MCLs for these substances could be set at a relatively low level. Small public and private supplies were identified as being more vulnerable to radionuclide contamination than public systems serving more than a few hundred people, but more investigation is needed to assess the extent of the exposure and its associated risk. The previous belief that high levels of Rn‐222 are confined to a few geographic areas was found to be false, largely because of a lack of a nationwide data base.
Evaluating Various Adsorbents and Membranes for Removing Radium From Groundwater
Authors: Clifford Dennis , Vijjeswarapu Winston , Subramonian Suresh
Published: February 2018

Field studies were conducted in Lemont, Ill., to evaluate specific adsorbents and reverse osmosis (RO) membranes for removing radium from groundwater. A radium‐selective complexer and barium‐sulfate‐loaded alumina appeared to have the best potential for low‐cost adsorption of radium from raw water or ion exchange brines, provided that the problem of the ultimate disposal of spent media can be solved. A new, low‐pressure (70‐psig) RO module achieved radium and total dissolved solids (TDS) rejections of 91 and 87 percent, respectively. Central treatment with standard or low‐pressure RO modules would be effective for radium removal—but expensive and unnecessary if TDS reduction is not also required. Point‐of‐use treatment using RO is effective for removing radium and may be cost effective for very small communities.
The Press and the Water Industry
Authors: Mannion John B.
Published: February 2018

The awarding of contracts for bulk purchases of water conservation kits by the Los Angeles Department of Water and Power is discussed. Water saving devices will be packaged in bulk quantities to make it easier for owners of large apartment complexes, condominiums, and townhomes to obtain their free water conservation devices.
Design Considerations for Package Water Treatment Systems
Authors: DeMers Larry D. , Hanzon Boyd D. , Glick Frank L. , Schultz Robert M.
Published: February 2018

Crested Butte is a rapidly growing winter and summer recreation resort in southern Colorado that attracts outdoor enthusiasts for its downhill and cross‐country skiing, fishing, hiking, bicycling, and other recreational activities. A consistently high quality water supply is extremely important because reports of an outbreak of waterborne disease would have dramatic economic repercussions for this mountain community. The existing treatment system needed to be upgraded, but climatic restrictions and cost considerations dictated that construction be completed quickly and cost effectively. The water district selected a package treatment plant to provide a traditional treatment train of flocculation, sedimentation, and filtration. The plant is easy to operate and has enabled the district to make efficient use of its two sources of supply.
Comparing Headspace With Purge and Trap for Analysis of Volatile Priority Pollutants
Authors: Wylie Philip L.
Published: February 2018

Headspace sampling is compared with purge‐and‐trap techniques for the gas chromatographic (GC) analysis of volatile pollutants in water. An objective comparison of the two sample introduction techniques was made by using the same GC, column, and detectors for identical analyses run first by purge and trap and then by headspace. Using optimized headspace conditions described in this article, this technique was as sensitive as the US Environmental Protection Agency purge‐and‐trap methods for the analysis of volatile pollutants in water. The precision for 24 sequential headspace injections was better than that for purge‐and‐trap analyses. The relative advantages and disadvantages for these two sampling methods are also discussed.
Ozone‐Induced Particle Destabilization
Authors: Grasso Domenic , Walter J. Weber
Published: February 2018

The purpose of this study was to gain insight into the mechanisms that are operative in ozone‐induced particle destabilization. Both the nature of background dissolved organic matter and the nature of the particles themselves were investigated. It appears that commercial humic acid preparations and natural dissolved organic matter respond differently to ozonation. The analyses performed suggest that polymerization of metastable organics is the primary mechanism responsible for ozone‐induced particle destabilization in a natural water–bentonite system.
Biological Processes in Drinking Water Treatment
Authors: Bouwer Edward J. , Crowe Patricia B.
Published: February 2018

Biological processes have the potential to remove pollutants that may be ineffectively removed by conventional treatment, such as biodegradable organics, synthetic organic compounds, ammonia, nitrate, iron, and manganese. Biooxidation of organic matter and ammonia decreases available substrates for microbial regrowth in distribution systems, reduces tastes and odors, and decreases the amount of precursor available to form disinfection by‐products. Biological removal of certain contaminants could extend the service time or capacity of subsequent physicochemical processes. In US water treatment, the practice is often to impair or preclude development of biological activity by prechlorination, rigorous scouring of filter media, and frequent backwashing of granular activated carbon. Practical experience in Europe with media containing microbial activity has been favorable.
Telling Our Side of the Story
Authors: Snider Harold E.
Published: February 2018

The author stresses the importance of public information efforts by the drinking water industry.
Small Systems Issue Appreciated
Authors: Cook Michael B.
Published: February 2018

The author questions the fact that there are no regulations regarding the disposal of point‐of‐use filters after they have allegedly removed pollutants such as radioactivity, pesticides, heavy metals, etc. from tap water. If this is the case, the used filters would be a hazard to refuse handlers and the pollutants may be reintroduced into the environment via landfills.
Slow Sand Filtration
Authors: Allen Martin J. , Bryck Jack , Hendricks David W. , Logsdon Gary S. , Bellamy William D. , Krill Robert M.
Published: February 2018

This article presents a panel discussion regarding slow sand filtration. The history of slow sand filtration, how it works, it advantages and disadvantages, its present uses, and how it compares to other filtration techniques, especially rapid sand filtration are presented.
Some Theoretical and Conceptual Views of Filtration
Authors: Amirtharajah Appiah
Published: February 2018

This article relates the fundamental concepts of granular media filtration to the major factors influencing the overall quality of filtered water. In present‐day theory, the particle removal mechanisms of transport, attachment, and detachment are described in two different modeling approaches: (1) phenomenological theories, and (2) trajectory theories. These theories are coupled with empirical evidence to stress the importance of chemical destabilization, initial degradation and filter ripening, minimization of rate changes, and the use of polymers for producing high quality water.
Soluble Manganese Removal on Oxide‐Coated Filter Media
Authors: Knocke William R. , Hamon Jeffrey R. , Thompson Carolyn P.
Published: February 2018

Laboratory‐scale filtration studies were conducted to assess the potential for soluble manganese removal within oxide‐coated, mixed‐media filtration systems. Filter column experiments employed both new anthracite coal and sand as well as oxide‐coated media obtained from three full‐scale water treatment facilities. Soluble and total manganese removals were evaluated as a function of parameters such as pH, presence or absence of an oxidant in the filter‐applied water, quantity and oxidation state of the filter media surface oxide coating, and temperature. Results indicated that Mn2+ removal was rapid and efficient under a variety of solution conditions. Alkaline pH conditions promoted efficient removal of Mn2+ on the oxide surface. Free chlorine likewise promoted soluble manganese removal on the media surface under both alkaline and acidic pH conditions. Stronger oxidants such as KMnO4, ClO2, and O3 resulted in Mn2+ oxidation immediately upon addition to the filter‐applied water. In these instances, manganese removal was accomplished by retention of colloidal MnOx(s) within the filter. Low‐temperature conditions did not appear to inhibit Mn2+ removal potential. The practical implications of this work for full‐scale treatment operations are also discussed.
Three Thoughts for the Price of One
Authors: Mannion John B.
Published: February 2018

The following standards have been designated as American National Standards by the American National Standards Institute, Inc. The date of ANSI approval for these standards is shown in parentheses: ANSI/AWWA C701‐88 (Dec. 1, 1988).
Identifying Vulnerable Surface Water Utilities
Authors: Clark Robert M. , Grayman Walter M. , Males Richard M. , Kilgore Roger
Published: February 2018

This study was conducted to provide a mechanism and framework with which utility managers could analyze the effects of upstream discharges on source waters. Specific components of the project included selection, implementation, and demonstration of a microcomputer‐based commercial data base management system for water quality information; selection and demonstration of a water quality model to represent the movement and transportation of pollutants in a surface water source; assessment of the availability of industrial and municipal discharge information from government sources; and applications of the data base management system, water quality monitoring, and data base development to the lower Mississippi River.
Asbestos in Drinking Water Supplied Through Grossly Deteriorated A–C Pipe
Authors: Webber James S. , Covey James R. , King Murray Vernon
Published: February 2018

High concentrations of asbestos were found in the water supply system of Woodstock, N.Y., following a routine pipe‐tapping operation in the fall of 1985. Analysis of a water sample collected 10 days after tapping showed asbestos concentrations in excess of 104 million fibers per litre (MFL). The source of this asbestos was asbestos–cement (AC) pipe, which was so deteriorated that sections of pipe could be easily broken by hand. Although asbestos concentrations decreased rapidly as AC pipe was removed from the system, concentrations as high as 49 MFL were measured during the summer of 1986. Throughout the sampling period, even when concentrations fell below 1 MFL, Woodstock water samples were characterized by fibers with much larger lengths, widths, and masses than those collected in nonproblem areas across New York state.
Using Activated Carbon to Remove Toxicity From Drinking Water Containing Cyanobacterial Blooms
Authors: Falconer Ian R. , Runnegar Maria T. C. , Buckley Tom , Huyn Van L. , Bradshaw Peter
Published: February 2018

Toxic blooms of cyanobacteria, including Anabaena species, which are neurotoxic, and Microcystis, which is hepatotoxic, are becoming increasingly common in potable water sources. Normal flocculation and chlorination processes do not remove the toxicity. The laboratory and pilot‐plant experiments described in this article showed that the toxicity can be removed by both powdered and granular activated carbon, with and without chlorination, alum flocculation, and polyelectrolyte addition.
Long‐Term Options for Municipal Water Conservation
Authors: Grisham Alice , Fleming William M.
Published: February 2018

Water conservation measures initiated by municipalities have usually been short‐term efforts to minimize the effects of a drought or other temporary water shortage. Now, because of increasing demands on limited water resources, water conservation measures are being reassessed as long‐term methods of reducing municipal water use. Long‐term measures require a somewhat different planning approach than do short‐term measures. Municipalities can choose from a variety of water conservation options, including metering and leak detection, building code revisions, water saving devices, water rates, landscaping changes, water use restrictions, and water reuse. Some of these options are more appropriate than others for individual cities. To ensure successful results, all conservation programs should include public education.
Long‐Range Financial Planning for Water Utilities
Authors: Brice Robert L. , Unangst Eric R.
Published: February 2018

Water utilities across the United States, especially those serving rapidly growing areas, have become aware of the need for long‐range financial planning to respond to changes in the nation's economy, to evaluate and plan for the impact of the 1986 Safe Drinking Water Act amendments on their operation and capital program, to accommodate changes in national tax legislation that significantly affect investment and bond markets, and to evaluate changing patterns of water use brought about by conservation efforts. This article focuses on the process the Tucson (Ariz.) Water Department uses to develop long‐range financial plans. The fundamental steps in this process are presented, including establishment of a mechanism for citizen involvement, formulation of policies that guide financial planning efforts, and identification of the components of a financial plan and of the tools utilized in the planning process. The preparation and publication of such plans have built confidence and credibility in Tucson Water among both customers and policy‐makers.
Long‐Term Contracts for Large Users: An Industry Viewpoint
Authors: Smith Ronald A.
Published: February 2018

General Motors Corp. (GM) negotiates rate and service contracts with its water suppliers as often as possible, based on fairness to the water utility, the utility's other customers, and GM. Water rates, in GM's view, should be adequate to maintain the operational and financial stability of the utility as a self‐supporting enterprise and should be based on the cost of service, without cross‐class customer subsidization or revenue subsidies. Detailed rate and service contracts are used by GM as vehicles to achieve these goals with its water suppliers.
Adsorption Equilibria of Natural Organic Matter After Ozonation
Authors: Harrington Gregory W. , DiGiano Francis A.
Published: February 2018

The equilibrium adsorption behavior of natural organic matter (NOM) subjected to coagulation and various levels of ozonation and biostabilization was investigated in bench‐scale experiments. The overall adsorbability of NOM increased with coagulation but decreased if coagulation was followed by ozonation and biostabilization. Without adsorption, ozonation was shown to enhance the biodegradability of coagulated NOM; up to 46 percent of total organic carbon was removed at the highest ozone dosage. The adsorption of NOM was described quantitatively by accounting for competitive adsorption among pseudocomponents and by applying concepts of polymer adsorption. Neither approach was entirely satisfactory for obtaining a systematic relationship between adsorbability and ozone dosage.