bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sensory GC analysis of decaying vegetation and septic odors
Authors: Khiari Djanette , Barrett Sylvia E. , Suffet I.H. (Mel) 
Published: February 2018

GC–MS is combined with sensory GC analysis to identify chemicals responsible for decaying vegetation and septic odors in drinking water supplies.A study was undertaken to identify the chemicals responsible for septic and decaying vegetation odors, not only in odor reference standards but also in natural waters. Two complementary extraction methods—closed‐loop stripping analysis and simultaneous distillation extraction—were used. Chemical identification was performed by gas chromatography (GC) with mass spectrometry, and sensory identification was accomplished by flavor profile analysis and sensory GC. Dimethyl disulfide, dimethyl trisulfide, and 2‐isobutyl‐3‐methoxypyrazine were the principal contributors to decaying vegetation odors, whereas dimethyl trisulfide and indole were strongly associated with septic odors. In addition, the study confirmed the presence of these chemicals as well as 2‐isopropyl‐3‐methoxypyrazine (associated with decaying vegetation) in water supplies.
Water availability under the Texas water rights system
Authors: Wurbs Ralph A. 
Published: February 2018

Simulation studies of demands on Texas water supplies point to the complexities of administering and modeling a water allocation system.Texas recently established a surface water rights permit system, similar to those of other western states. A simulation study of the Brazos River Basin identified issues and concerns that illustrate the practical complexities of administering and modeling a water allocation system. Key considerations involve sharing of limited supplies by numerous water users during drought, reservoir storage priorities, multiple‐reservoir system operations, water quality constraints, return flows, hydrologic data compilation, and reliability assessment. The issues affecting evaluation of water availability within the Texas water rights system are representative of other states as well.
Evaluating criteria for enhanced coagulation compliance
Authors: White Mark C. , Thompson Jeffrey D. , Harrington Gregory W. , Singer Philip C. 
Published: February 2018

Jar testing of 31 natural waters suggests many utilities may need the proposed alternative performance criterion to comply with enhanced coagulation specified in the proposed D/DBP Rule.Jar tests were performed on 31 natural waters from a variety of sources across the United States. These tests indicate that the majority of utilities supplying samples will have difficulty meeting the Step 1 total organic carbon (TOC) removal requirements in the Disinfectants/Disinfection By‐products Rule. Utilities may need the proposed point of diminishing returns alternative performance criterion to achieve compliance with the enhanced coagulation requirement. Water sources with high TOC and low alkalinity were most likely to meet the proposed Step 1 TOC requirements. Those with low TOC were most likely to need the alternative performance criterion.
Testing the SANCHO model on distribution systems
Authors: Laurent Patrick , Servais Pierre , Prévost Michèle , Gatel Dominique , Clément Bernard 
Published: February 2018

A deterministic model to predict microbiological water quality in distribution systems is tested by comparing field data measurements and predicted values obtained through model simulations.Empirical findings were used to evaluate a deterministic model of bacterial dynamics in a pipe carrying potable water. The SANCHO model simulates the response of fixed and free bacteria in the system to the concentrations of chlorine and organic substrate entering the system. The authors tested the model on seven full‐scale distribution systems and made a study of the error distribution between measured values and the model's predicted values. Various simulation examples demonstrate the usefulness of the model for determining a bacterial regrowth control strategy for distribution systems. Coupled with residence time calculation software, the SANCHO model may become an important decision‐making tool in the management of water distribution systems. The model is particularly useful in that it can help define the reduction thresholds for biodegradable dissolved organic carbon required to maintain a given network's quality objectives as a function of the residence time of the water in the system.
Committee report: transit‐time ultrasonic flowmeters
Authors:   AWWA Subcommittee on Ultrasonic Devices
Published: February 2018

A review of transit‐time ultrasonic flowmeter principles and operation lays the groundwork for development of an AWWA standard on flowmeter selection.AWWA has not yet developed a standard providing guidelines for selecting transit‐time ultrasonic flowmeters from among the numerous models and designs available. As a first step toward developing such a standard, the AWWA Subcommittee on Ultrasonic Devices, a subsection of the AWWA Committee on Rate Type Flowmeters, has documented the state of the art in transit‐time flowmeters. This report presents committee findings to date for public review and information. The committee welcomes comments from manufacturers, prospective users, and other parties interested in transit‐time flowmeters.
DAF pretreatment: its effect on MF performance
Authors: Braghetta Anne , Jacangelo Joseph G. , Chellam Shankararaman , Hotaling Michael L. , Utne Bruce A. 
Published: February 2018

A pilot study suggests that DAF pretreatment helps reduce membrane fouling in hollow‐fiber MF.A pilot study investigated the use of dissolved air flotation (DAF) as a pretreatment to hollow‐fiber microfiltration (MF). Results showed that DAF‐pretreated feedwater achieved longer MF runs than raw feedwater. MF performances with DAF‐pretreated water were compared for fluxes of 70, 90, 110, and 135 gfd (120, 155, 190, and 230 L/m2/h). Performance results indicated that MF run lengths of more than 30 days could be achieved at flux conditions of 70 and 90 gfd (120 and 155 L/m2/h), with run lengths of 21 and 10 days for fluxes of 110 and 135 gfd (190 and 230 L/m2/h). Experimental results from this pilot study were also interpreted using a mathematical model to determine MF backwash efficiency at the different flux conditions. Both the experimental and modeling results suggest that membrane fouling by the DAF‐pretreated water was characterized by reduced pore blockage and lower cake compressibility as compared with treatment of raw feedwater.
Reduction of microscopic particulates by aquifers
Authors: Gollnitz William D. , Clancy Jennifer L. , Garner Stephen C. 
Published: February 2018

The authors introduce a method for evaluating natural reduction of microscopic particulates in aquifers that store groundwater under the direct influence of surface water.Many water utilities operate collection devices constructed in alluvial‐valley aquifers. Pumping groundwater from these systems may induce infiltration of surface water containing pathogenic protozoa. However, the porous sand and gravel of this kind of aquifer can significantly reduce the number of microscopic particulates that pass through the aquifer media. A method is proposed for evaluating the natural reduction efficiency of porous‐media aquifers, taking into consideration the transport of particulates through the aquifer during a period of maximum infiltration. The method allows regulators to estimate the risk of pathogenic protozoa, determine the log‐reduction credit warranted by the water's transport through the aquifer, and determine the type of treatment needed for the source.
COMMITTEE REPORT: Climate change and water resources
Authors:   AWWA's Public Advisory Forum
Published: February 2018

Global warming is a fact, and water resource managers need to plan accordingly.Global climatic change—the greenhouse effect—is here to stay. Although uncertainties remain about the nature and extent of climatic changes that will occur, most among the scientific community believe changes in the hydrologic cycle and to water resource management systems will be significant. Water managers, policy‐makers, and the public should begin to consider the implications of climatic change for long‐term water planning and management. AWWA's Public Advisory Forum has discussed this problem for the past two years. The recommendations it offers in this article are not for specific changes in operations, for complicated or costly new infrastructure or development, or for irreversible actions. Instead, they are recommendations for thoughtful analysis of water systems' vulnerabilities to unprecedented climate change and for attention, planning, and continued vigilance in response to this situation. As the proverb says, to see the future is good, but to prepare for it is better.
Evaluating particle counters
Authors: O'Shaughnessy Patrick T. , Barsotti Michael G. , Fay James W. , Tighe Scott W. 
Published: February 2018

Comparisons of particle counts made by counters and counts made by microscopic processes suggest counters accurately indicate removal efficiency.Particle counting methods for use in a water treatment facility were analyzed to compare counts made by a particle counter with a forward‐angle light scatter (FALS) sensor with counts made with a scanning electron microscope and by microscopic particulate analysis. A separate study compared an FALS sensor with a light obscuration sensor when challenged with latex spheres and cultured microorganisms and when performing continuous in‐line counts of the facility's filter effluent. Log removal values were comparable among the particle counting methods and did not vary significantly across various size ranges of an FALS sensor. Microorganisms were undersized by both sensor types compared with sizes determined with an optical microscope. These results suggest counters accurately indicate facility particle removal efficiency. However, counts made by a particle counter within a specific size range should be interpreted after characterizing the nature of the particles in the source
Water quality reports boost consumer confidence
Authors: Jordan Charles G. 
Published: February 2018

The consumer confidence report, which is really a water quality report, is an opportunity to communicate with customers.By late 1998, according to provisions in the reauthorized Safe Drinking Water Act, all community water systems will be required to produce an annual consumer confidence report—really a water quality report—for their customers. Consumers will gain confidence if they learn what their drinking water contains, how it might affect them, and what the utility is doing about potential problems. Utility managers should approach this report more as a communication exercise than a technical exercise. Simplicity is the key to providing an effective water quality report for customers. This article describes how a water system can produce a consumer confidence report that informs customers and complies with the law.
Bubbling to the surface: public water supply issues
Authors: Bishop Bojinka 
Published: February 2018

Water suppliers are grappling with drinking water issues that fundamentally affect public policy.Significant forces including public criticism and publicity about water quality problems have caused public issues about water supply to be raised. Consequently, the “silent service” has begun a dialogue with the public. Currently, the industry's voice is only a whisper, and sometimes it's hoarse, but progress has been made—especially on the local level. For more effective analysis and response, this article characterizes public water supply issues as outsider, insider, local, and latent. Because many of these issues are fundamental to sound social and public policy, the water supply industry should play a more active role in setting public policy.
Public affairs step by step
Authors: Faulkner‐Vaughn Linda 
Published: February 2018

The author spotlights innovative public affairs activities and offers step‐by‐step instructions for creating a public affairs program.Public affairs programs come in all shapes and sizes. From large utilities like the East Bay Municipal Utility District in Oakland, Calif., to small‐town operations like the Georgetown County (S.C.) Water and Sewer District, utility managers across the United States are realizing that public affairs is an important component of a water provider's operation. Conversations with program directors show that public affairs programs may have similar components, but each is unique in how it responds to the needs, demands, and interests of the particular community it serves.
Deposition and retention of bacteria in backwashed filters
Authors: Hozalski Raymond M. , Bouwer Edward J. 
Published: February 2018

Biomass accumulation in laboratory‐scale filters is not impaired by backwash with water alone.Experiments tracked the deposition of two model bacteria—Pseudomonas aeruginosa and Klebsiella pneumoniae—onto clean filter media (i.e., glass beads and filter sand) and the subsequent removal of the bacteria by backwashing. The ability of bacteria to accumulate and be retained in a frequently backwashed filter is critical for effective removal of biodegradable organic matter in a process termed biofiltration. Column filtration experiments showed that the bacteria, especially P. aeruginosa, readily attached to the filter media during filtration, despite unfavorable chemical conditions. Water backwash was not effective at removing bacteria from the filter media, with only 20–40 percent removal during 10‐min backwash cycles at hydraulic loading rates ranging from 23 to 53 m/h (9.3 to 22 gpm/sq ft) and bed expansions ranging from 15 to 50 percent. Incomplete removal of biomass during backwashing was beneficial for removal of biodegradable total organic carbon, typically allowing a backwashed biofilter to maintain treatment at levels similar to the period immediately preceding the backwash.
New horizons in federal regulation
Authors: Pontius Frederick W. 
Published: February 2018

New requirements and schedules have dramatically accelerated the pace of regulatory activity.The US Environmental Protection Agency is in the process of responding to the mandates imposed by the 1996 Safe Drinking Water Act amendments. New requirements and regulatory schedules have dramatically accelerated the pace of regulatory activity. Several new rules are mandated, such as those that cover microorganisms and disinfection by‐products, arsenic, uranium, radon, groundwater disinfection, and filter backwash recycling. New contaminants for regulation will be identified using a listing process through which the agency will decide whether candidate contaminants warrant regulation.
Cost to utilities of a lower MCL for arsenic
Authors: Frey Michelle M. , Owen Douglas M. , Chowdhury Zaid K. , Raucher Robert S. , Edwards Marc A. 
Published: February 2018

Water utilities need to begin now to evaluate their costs for complying with a lower MCL for arsenic.Compliance with a revised arsenic maximum contaminant level (MCL) for drinking water will require a substantial cost to water suppliers in the United States. A rigorous methodology was developed to estimate the national cost of complying with alternative regulatory limits for arsenic. This methodology considered the feasibility of available technologies based on existing treatment at utilities that are not in compliance and the level of water quality constituents that limit technology performance. A least‐cost method of selecting treatment alternatives was used to estimate compliance costs and the results were extrapolated nationally. Estimated national compliance costs ranged from $330 million per year for a 20‐μg/L MCL to more than $4.1 billion/year for a 2‐μg/L MCL. These estimates represent a 10‐ to 20‐fold increase in the US Environmental Protection Agency's (USEPA's) preliminary cost estimates. Although the effect on small systems would be substantial, this study found that the cost burden would be shared equally between small (<10,000 people served) and large (>10,000 people served) systems. USEPA also found that systems using groundwater would bear more of the total costs (62 to 82 percent) than systems using surface water.
Considerations in As analysis and speciation
Authors: Edwards Marc , Patel Sapna , McNeill Laurie , Chen Hsiao‐wen , Frey Michelle , Eaton Andrew D. , Antweiler Ronald C. , Taylor Howard E. 
Published: February 2018

A modified field technique can quantify particulate As, soluble As(III), and soluble As(V) in drinking water.Several problems with commonly used techniques that analyze for arsenic are reported, and solutions are proposed. Analytical techniques can accurately detect <0.5 μg/L total arsenic if certain conditions are met: iron, nitrate, and other interferences are overcome in hydride generation techniques, poor recoveries are overcome in graphite furnace atomic adsorption techniques, and chloride interferences are accounted for in inductively coupled plasma mass spectrometry techniques. Because no techniques adequately preserve arsenic species during storage, a speciation protocol that is fast (about 5 min/sample), relatively inexpensive (about $10/resin column), and user‐friendly and that can be applied in the field was developed. Particulate arsenic represents a significant fraction of total arsenic in drinking water.
Route restructuring reduces meter‐reading costs
Authors: Bienlien Kent D. , Adams Daniel J. , Cunningham Brian S. 
Published: February 2018

Computer software makes restructuring a much faster process and meter‐reading less costly.Restructuring meter routes is one way to increase productivity and efficiency and reduce costs. The route restructuring trial described in this article was designed to quantify the benefits of using commercial restructuring software. The cost to read a meter before route restructuring (based on an average of 224 meters per day) was estimated at $0.958; after restructuring, it was $0.699 (307 meters per day), a 27 percent reduction in labor costs. Labor cost to restructure the routes was reduced by an estimated 83 percent. Used effectively, route restructuring software increases the productivity of meter readers and efficiently tracks and manages all aspects of the work.
Dewaterability of alum and ferric coagulation sludges
Authors: Thompson Phillip L. , Paulson Wayne L. 
Published: February 2018

Ferric sulfate sludges demonstrated superior dewaterability over sludges formed by coagulation with aluminum.Tighter regulations governing stream discharge of coagulation sludge from the primary sedimentation process prompted the University of Iowa Water Treatment Plant to consider sludge‐handling options. This pilot study was undertaken in order to investigate differences in the mechanical dewatering of sludges formed by using either alum or ferric sulfate coagulants. The approach used various volumes of wasted lime sludge produced from the plant's softening process as a filtering aid. After the short pilot study, dewatering data from a bench‐scale plate‐and‐frame filter press indicated that ferric sludge was easier to dewater than sludges formed by coagulation with alum. The addition of lime‐softener sludge increased the dewaterability of all sludges tested, primarily by increasing the sludge feed solids concentration, which may have also decreased blinding.
Oregon's SDWRLF gets under way
Authors: Leland Dave , Wise Doug 
Published: February 2018

Oregon takes a step‐by‐step approach to setting up a state drinking water revolving loan fund.The 1996 Safe Drinking Water Act amendments established a Drinking Water State Revolving Fund (DWSRF) to help states and their community drinking water systems meet regulations. Oregon's efforts to secure and administer its share of the DWSRF led to the design and development of the state Safe Drinking Water Revolving Loan Fund (SDWRLF). The SDWRLF program was developed over the course of 18 months in close cooperation with the Oregon Drinking Water Advisory Committee, the Oregon Health Division, the Oregon Economic Development Department, and the Oregon Department of Environmental Quality. The design that emerged from their collaborative contributions represents a significant effort to improve and protect public drinking water systems in the state.
SDWA capacity development
Authors: Shanaghan Peter E. , Kline Ian P. , Beecher Janice A. , Jones Ralph T. 
Published: February 2018

Using stakeholder comments, USEPA is creating guidance and information to smooth implementation of SDWA capacity development provisions.The capacity development provisions of the 1996 Safe Drinking Water Act offer a flexible framework within which states and water systems can work together to ensure that systems acquire and maintain the technical, financial, and managerial capacity needed to consistently achieve the public health protection objectives of the act. Capacity development is related to the Drinking Water State Revolving Fund (DWSRF) in two important ways: states may set aside funds from their DWSRF allotments to develop and implement capacity development programs, and the US Environmental Protection Agency (USEPA) is required to withhold DWSRF funds from states that fail to implement the capacity development provisions. USEPA's implementation of the capacity development provisions is being guided by an unprecedented process of stakeholder consultation and involvement.
Implementing a DBO project
Authors: Kelly Elizabeth S. , Haskins Scott , Reiter Paul D. 
Published: February 2018

The process of implementing Seattle's Tolt design‐build‐operate project provides a road map for other utilities interested in alternative contracting approaches.The city of Seattle, Wash., used an innovative public‐private partnership to develop its first water filtration plant. The new Tolt treatment facilities will increase system reliability and flexibility by allowing continuous operation of Seattle's Tolt source through periods of high turbidity. It will also improve system yield and allow long‐range compliance with anticipated regulations. As an alternative to the conventional public works procurement process, Seattle created a design‐build‐operate (DBO) model to provide reliable, cost‐effective project development while maintaining public ownership of the facility. The DBO contract is valued at $101 million, which represents a savings of $70 million over the $171‐million estimated cost of developing the same facility using conventional design‐bid‐build procurement with city operations for 25 years. The Tolt facility, expected to be operational in late 2000, will be a 120‐mgd (45 106‐m3/d) filtration and ozonation plant for treatment of Seattle's Tolt River source of supply, which provides about a third of the water for Seattle and its 26 regional wholesale customers.
Detection limits of organic contaminants in drinking water
Authors: Draper William M. , Dhoot Jagdev S. , Dhaliwal Joginder S. , Remoy John W. , Perera S. Kusum , Baumann Frank J. 
Published: February 2018

Better control of MDL determination will substantially reduce interlaboratory variation.This article examines some of the experimental variables that can contribute to the observed variability in laboratory performance. The examples provided suggest that method detection limits (MDLs) would be more uniform among laboratories if (1) uniform spike concentrations were used in MDL determination; (2) analytical methods were more uniform as to procedures, reagents, and materials; and (3) tighter guidelines were established for conducting MDL experiments and handling MDL data. The pooling of data from multiple spike levels (or any other means to increase sample size) minimizes random error in MDL determination. Improved control in MDL determination would lead to better information on laboratory capabilities, and this in turn would improve the technical basis for reporting limits, trigger levels, and water quality standards.