bluuebunny/crossref_metadata_2025_split huggingface dataset:
ICR survival guide
Authors: Nieminski Eva C. , Chaudhuri Sanwat , Flint Tage I. , Paxman Scott W. , Reynolds Florence P. , Carman John R. 
Published: February 2018

Utah utilities gained practical experience during an 18‐month practice run of quarterly analyses under the ICR protocol.In August 1994, in a cooperative, nonregulatory effort, a pre‐Information Collection Rule (ICR) testing program was initiated by Utah Division of Drinking Water, Utah Department of Health Laboratory, and the five largest water utilities in Utah. As part of a larger water quality enhancement program, the participating utilities conducted quarterly analyses under the ICR protocol for 18 months. Samples were collected from 10 plants and analyzed according to proposed ICR protocols for general water quality, microbial contaminants, and disinfection by‐products. Two utilities and the Utah Division of Drinking Water participated in the alpha and beta testing of the ICR utility software, and the ICR laboratory software was tested at the Utah Department of Health Laboratory. The experience gained in this effort in determining the time, effort, and resources necessary for sampling, testing, and reporting and in finding practical solutions to potential problems should help utilities across the country prepare for the ICR.
Multiagency approach to water quality enhancement
Authors: Nieminski Eva C. , Reynolds Florence P. , Carman John R. , Flint Tage I. , Pitcher David O. , Paxman Scott W. 
Published: February 2018

Important public health protection benefits can result from the type of cooperative effort the authors describe.The five largest water utilities in Utah and the State Department of Environmental Quality (DEQ) formed the Utah Water Quality Alliance to strive to produce drinking water of the best quality. The alliance was designed to monitor both source water and treated water quality, optimize treatment processes, and evaluate new technologies to further reduce contaminants of concern. The alliance's activities fulfilled many of the criteria of a subsequently proposed national water quality enhancement program, the Partnership for Safe Water. Each utility has benefited from this multiagency and cooperative approach by opening communication lines, securing additional funding through the participation of the state DEQ, and sharing expertise to accomplish complex tasks such as tracer studies and extensive monitoring programs (e.g., the pre‐Information Collection Rule study).
The Las Vegas cryptosporiisis outbrak
Authors: Roefer Peggy A. , Monscvitz J.T. , Rexing David J. 
Published: February 2018

An outbreak of cryptosporidiosis in a drinking water system with no apparent treatment deficiencies or breakdowns suggests that waterborne outbreaks are a potential threat in other US cities.When Las Vegas, Nev., experienced an outbreak of cryptosporidiosis in the AIDS population early in 1994, the Clark County Health District requested that the Centers for Disease Control and Prevention (CDC) assist in determining the cause of the outbreak. Results of CDC's epidemiological study indicated that AIDS patients drinking tap water in Las Vegas are at greater risk of contracting cryptosporidiosis than if they consume bottled or filtered water. An AWWA Research Foundation peer review panel concurred with the CDC that the epidemiologic evidence pointed to tap water as the only risk factor in the outbreak. The paradox of this outbreak is that the influent water quality at the treatment plant did not change, no treatment breakdowns or deficiencies were identified, and the outbreak ended as suddenly as it began, with no changes in water treatment.
Mathematical modeling of PAC adsorption processes
Authors: Najm Issam N. 
Published: February 2018

Easy‐to‐use models for PAC adsorption processes are presented.Recently, great strides have been made in modeling the adsorption of organic compounds onto powdered activated carbon (PAC), specifically with the conversion of the partial differential equations of the homogeneous surface diffusion model to algebraic nonlinear equations. The solutions of these equations are easy to obtain using nonlinear equation‐solving techniques (such as Newton's method) and are as accurate as the partial differential equation solutions obtained using labor‐intensive numerical techniques. A new method using these algebraic equations has been developed to determine the value of the surface diffusion coefficient Ds from adsorption batch kinetic tests. A nondimensional parameter λ = (t Ds/R2) can be used to evaluate the performance of PAC in a continuous‐flow process. A λ value > 0.1 implies that the adsorption process is highly efficient, in that more than 75 percent of the PAC adsorption capacity is being utilized. On the other hand, a λ value < 0.01 implies that the adsorption process is highly inefficient, in that less than 30 percent of the PAC adsorption capacity is being utilized.
Integrating conservation into water supply planning
Authors: Maddaus William O. , Gleason Gwendolyn , Darmody John 
Published: February 2018

How can water suppliers achieve an appropriate balance between capacity expansion and conservation?Finding an appropriate balance between capacity expansion and conservation can result in quantifiably reduced demand, which yields benefits for water utilities. One benefit is reduction in operation and maintenance expenses, because less pumping energy and fewer chemicals are used in the acquisition, treatment, and disposal of water. Another benefit is the deferral or downsizing of capital facilities. Comparing current supply with projected demand aids in the identification of future needs for demand management or increased supply. In addition to cost factors, nonmonetary factors, including environmental effects, should be considered. In this article, case studies from Texas, California, Idaho, and New Zealand illustrate this balancing process.
Watershed protection for New York City's supply
Authors: Ashendorff Arthur , Principe Michael A. , Seeley Anne , LaDuca John , Beckhardt Larry , Faber Walter , Mantus Jeff 
Published: February 2018

New York City is making every effort to protect its watershed to assure water quality and maintain filtration avoidance.Since 1987, New York City has enhanced its comprehensive watershed monitoring program (including pathogen monitoring), developed a disease surveillance and outbreak detection program, and implemented a watershed protection program that has improved water quality. The city recognized that high‐quality source water and effective watershed protection are the foundation of filtration avoidance under the federal Surface Water Treatment Rule (SWTR). Accordingly, the city applied for and received filtration avoidance determinations for the Catskill and Delaware portions of its system. This article summarizes the city's water quality data and watershed monitoring and protection programs in the context of the SWTR. A Watershed Memorandum of Agreement, signed Jan. 21, 1997, provides for land acquisition, updated watershed regulations, and partnership programs. As part of the watershed agreement, USEPA issued a four‐month interim filtration avoidance and will issue a revised filtration avoidance later in 1997. Provided the city meets certain provisions, this will allow it to avoid filtering the Catskill and Delaware supplies until at least Apr. 15, 2002.
FPA of selected odorous compounds
Authors: Rashash Diana M.C. , Dietrich Andrea M. , Hoehn Robert C. 
Published: February 2018

Flavor profile analysis proves to be a reliable method of evaluating odors in water, especially when performed by well‐trained panelists using familiar descriptors.The odors of 15 organic compounds were evaluated by the flavor profile analysis (FPA) method. The FPA data were well described by the Weber‐Fechner law, as indicated by the R2 values (0.6–0.99). Odor threshold concentrations were obtained and ranged from <0.01 μg/L (geosmin, 2‐methylisoborneol, and 2t,6c‐nonadienal) to 60 μg/L (phenethyl alcohol). Changes in qualitative descriptors were observed among structurally related compounds and with changes in compound concentration; thus, exposing FPA panelists to a variety of compounds, each at several concentrations, will aid in familiarizing the panelists with the diverse odor descriptors that can be encountered.
Evaluating an AOP for TCE and PCE removal
Authors: Karimi Ali A. , Redman Jeremy A. , Glaze William H. , Stolarik Gary F. 
Published: February 2018

The authors evaluate an AOP by introducing elevated TCE and PCE into groundwater and propose a chemical kinetic model for evaluating AOP performance.A full‐scale evaluation of an advanced oxidation process (AOP) involving the use of ozone (O3) and hydrogen peroxide (H2O2) at a 126‐L/s (2,000‐gpm) flow rate was completed in a plug‐flow hydraulic regime by the Los Angeles (Calif.) Department of Water and Power. This facility is the first full‐scale AOP for trichloroethylene (TCE) and tetrachloroethylene (PCE) treatment in the United States, if not the world. The purpose of this study was to challenge the performance of the plant with typical groundwater pollutants, propose a kinetic model for the process, and confirm past laboratory and pilot studies. Groundwater containing up to 447 μg/L TCE and 163 μg/L PCE was treated to below the maximum contaminant (MCL) level of 5 μg/L. The optimum H2O2/O3 dose ratio was 0.5–0.6. Removal efficiency of TCE and PCE declined as groundwater alkalinity increased. Investigation of by‐product formation showed formation of assimilable organic carbon and bromate following the treatment process. A kinetic model calibrated using the experimental data predicted the concentration of TCE and PCE in the finished water reasonably well.
Microfiltration operating costs
Authors: Gere Andrew R. 
Published: February 2018

Microfiltration provides affordability, reliability, and superior finished water at the San Jose Water Company.In February 1994, the San Jose (Calif.) Water Company began operating a 5‐mgd (19 × 103–m3/d) microfiltration (MF) plant as part of the Saratoga Water Treatment Plant. The cost of operating the MF plant during 1995 was determined for all noncapitalized expenditures including power, operator labor, chemicals, membrane replacement, maintenance, and repairs. Actual operating costs were $309/mil gal ($82 × 103/m3). Production costs for a direct filtration plant treating similar water during the same time period were 20 percent of those for the Saratoga MF plant, largely because of a significant economy of scale and lower power costs. Treatment plant performance, reliability, and operating experience affect the overall cost of treated water. In its fourth year of operation, the MF plant continues to be appropriate for this water supply because it is reliable and easy to operate and provides superior finished water quality.
Nanofiltration: from prototype to full scale
Authors: Ventresque Claire , Turner Greg , Bablon Guy 
Published: February 2018

A nanofiltration membrane tailor‐made to address site‐specific concerns proves capable of overcoming both variable operating conditions and inherent membrane deficiencies.At a water facility in the Paris suburbs, a prototype nanofiltration (NF) plant was used to assess NF membrane performance prior to design and construction of a large‐scale expansion to an existing plant. Prototype operation uncovered both the successes and deficiencies in membrane performance, particularly with regard to the source water supplying the plant. In response to these concerns, a new membrane was developed in partnership with the membrane manufacturer. In parallel with the prototype work conducted in France, a similar membrane assessment was carried out in England. Results from both pilot‐plant operations indicate that an NF membrane manufactured to meet site‐specific concerns can overcome variable operating conditions and treat large water flows.
Arsenic removal by RO and NF membranes
Authors: Waypa John J. , Elimelech Menachem , Hering Janet G. 
Published: February 2018

RO and tight NF membranes prove equally effective in removing As species over a wide range of operational conditions.Bench‐scale experiments were performed to assess the effectiveness of reverse osmosis (RO) and nanofiltration (NF) membranes in removing arsenic (As) from synthetic freshwater and source water. The authors examined the effects of operational conditions (applied pressure and feedwater temperature) and solution chemical composition (As oxidation state, pH, and presence of co‐occurring inorganic solutes). Both As(V) and As (III) were effectively removed from synthetic freshwater by RO and tight NF membranes over a wide range of operational conditions. The relatively large molecular weight (>125 g/mol) of the As species governed their separation behavior. Applied pressure had little effect on As removal, but an increase in feedwater temperature decreased As removal by a small percentage. Removals of As (III) and As(V) were comparable, with no significant preferential rejection of As(V) over As (III). Variations in solution pH from 4 to 8 also did not affect the removal of As species by the membranes tested, despite changes in the speciation and charge of As(V). Co‐occurring inorganic solutes had only a slight effect on As removal. Removal of As from source water was comparable to that obtained with synthetic freshwater, despite the presence of turbidity, natural organic matter, and a variety of co‐occurring solutes.
Biological filtration for BOM and particle removal: a critical review
Authors: Urfer Daniel , Huck Peter M. , Booth Stephen D.J. , Coffey Bradley M. 
Published: February 2018

The authors review key parameters and engineering variables influencing biological filtration and identify areas requiring further research.Biological filtration, an important process step for the production of microbially safe and aesthetically pleasing drinking water, has attracted increased attention within the water industry. In many cases, the most economical way to implement biological rapid filtration is to achieve biodegradable organic matter (BOM) removal and particle removal within the same filter unit, i.e., single‐stage biological filtration. This requires optimization of the filtration process, keeping in mind both treatment goals: BOM and particle removal. This article presents a critical review of the key parameters and engineering variables influencing the biological performance, as well as the conventional performance, of biologically active filters. Several areas requiring further research have been identified.
Crypto and Giardia in US groundwater
Authors: Hancock Carrie M. , Rose Joan B. , Callahan Michael 
Published: February 2018

Groundwater systems need to be carefully monitored until contamination levels and acceptable risk factors are determined.Data generated from the detection of Cryptosporidium oocysts and Giardia cysts in 463 groundwater samples were compiled. Samples were taken from 199 sites in 23 of the 48 contiguous states. The groundwater sources were vertical wells, springs, infiltration galleries, and horizontal wells. Samples were analyzed using an immunofluorescence technique. Inclusion of data from all sources showed that 12 percent of the sites were positive for Cryptosporidium or Giardia or both. Cryptosporidium oocysts were found in 5 percent of the vertical wells, 20 percent of the springs, 50 percent of the infiltration galleries, and 45 percent of the horizontal wells. Giardia cysts were found in 1 percent of the vertical wells, 14 percent of the springs, 25 percent of the infiltration galleries, and 36 percent of the horizontal wells. These data suggest that springs are at a higher risk for contamination than vertical wells. Because pathogens occur frequently in infiltration galleries and horizontal wells, these sources warrant further study.
Removing particles and THM precursors by enhanced coagulation
Authors: Vrijenhoek Eric M. , Childress Amy E. , Elimelech Menachem , Tanaka Theodore S. , Beuhler Mark D. 
Published: February 2018

A pilot‐scale study shows that enhanced coagulation removes both particles and THM precursors.The effectiveness of enhanced coagulation for removing particles and trihalomethane (THM) precursors at various alum dosages and coagulation pH values was assessed. Samples of both source water and filter effluent were examined by counting particles and measuring particle size distribution, turbidity, total organic carbon, ultraviolet light absorbance at 254 nm (UV254), and THM formation potential. Removal of particles and turbidity increased substantially at alum dosages above 20 mg/L. Particle removal was not significantly different at adjusted pH (5.5) compared with ambient pH. Filter effluent particle counts were consistent with residual turbidity data; however, particle counting provided more information on the efficiency of the solid‐liquid separation. Significantly more THM precursors were removed by enhanced coagulation at pH 5.5 than at ambient pH. Higher dosages were needed to achieve acceptable removal of THM precursors than were needed for removal of particles.
Monitoring DBP formation with differential UV spectroscopy
Authors: Li Chi‐Wang , Korshin Gregory V. , Benjamin Mark M. 
Published: February 2018

A new application uses differential UV spectroscopy to monitor DBP formation easily, rapidly, and inexpensively.The decrease in the ultraviolet (UV) absorbance of natural organic matter (NOM) induced by chlorination can be characterized by the differential UV spectrum of the water. Differential UV spectra of chlorinated NOM are remarkably similar for a wide range of water qualities and chlorination conditions, always exhibiting a band with a maximum near a wavelength of 272 nm. The magnitude of the decrease in A272 (ΔA272) is an excellent indicator of total organic halogen (TOX) formation resulting from chlorination, independent of the ratio of chlorine to dissolved organic carbon, bromide concentration, pH, reaction time, and NOM source. Use of ΔA272 as a surrogate allows virtually instantaneous and continuous monitoring of TOX and in some cases, specific disinfection by‐products, at a much lower cost than is possible using conventional analytical approaches.
Effects of backwashing on biological filters
Authors: Ahmad Rasheed , Amirtharajah A. , Al‐Shawwa A. , Huck Peter M. 
Published: February 2018

A pilot study identifies concerns and strategies for successful performance of biological filters.The success of biological filtration depends on careful control and maintenance of the amount of biomass on the media during the maturation period and backwashing as well as during sudden changes in hydraulic loading. Various backwashing strategies and hydraulic transients were studied to determine how they affected filtration performance of biofilters in terms of effluent quality and head loss. Biological filters backwashed with a combination of air plus subfluidization water flow at collapse pulsing, followed by water wash with 25 percent bed expansion, can produce a water low in assimilable organic carbon (AOC). Compared with air‐scoured filters, water‐washed filters produced lower initial peaks during ripening and similar effluent AOC. Chlorinated backwash affects biological activity. Under the conditions of these experiments, chlorinated backwash produced higher AOC and nonpurgeable organic carbon in the filter effluent. A sudden 30 percent increase in hydraulic loading had a greater effect on biological filtration performance than on conventional filtration, accelerating filter breakthrough and causing poorer effluent quality.
Maintaining quality without a disinfectant residual
Authors: van der Kooij Dick , Hein J. , van Lieverloo M. , Schellart Jon , Hiemstra Peter 
Published: February 2018

Good engineering practices and biostable drinking water and materials help ensure the quality of Dutch drinking water during distribution without use of a disinfectant residual.Preservation of the microbial quality of drinking water during distribution is a main objective in water supply. Although a disinfectant residual reduces the concentration of suspended bacteria, it has only a limited effect on microorganisms in biofilms and sediments or on microbial contaminants. Furthermore, a disinfectant residual affects taste and odor and results in the presence of compounds with toxic properties. Maintenance of an effective residual throughout the distribution system is hampered by disinfectant decay caused by pipe materials and compounds present in the water. The Netherlands depends on good engineering practices in the distribution system to prevent microbial and chemical contamination. Regrowth can be limited by distributing biostable drinking water and applying biostable materials in contact with drinking water.
Benefits of using a disinfectant residual
Authors: Haas Charles N. 
Published: February 2018

Given the age and vulnerability of some US water distribution systems, use of a disinfectant residual as an added safeguard makes sense.Water distribution systems in the United States routinely carry chlorine residuals < 0.05 mg/L and invariably carry residuals > 0.1 mg/L. This article outlines some of the benefits of using chlorine as a disinfectant residual and considers system characteristics (e.g., system age and vulnerability) that support this application. Benefits accruing to maintenance of a chlorine residual include protecting against modest degrees of intrusion of contaminants, serving as a sentinel for the presence of such contamination, and reducing the potential for growth of heterotrophic organisms.
Comparison of mineral acid pretreatments for sulfide removal
Authors: Duranceau Steven J. , Anderson Robert K. , Teegarden Robert D. 
Published: February 2018

Both sulfuric and carbonic acid improved sulfide removal by lowering pH, but only carbonic acid preserved alkalinity and proved less corrosive.To determine water quality effects on groundwater treatment for hydrogen sulfide, the authors compared sulfuric acid (H2SO4) and carbonic acid for pH adjustment pretreatment in a pilot‐scale (40‐gpm [2.5‐L/s]) randomly oriented packed tower. Pretreatment with either H2SO4 or carbon dioxide (CO2) to pH 6.0 resulted in > 95 percent sulfide removal for tower feedwater sulfide concentrations of 2.5 mg/L. However, utilization of H2SO4 for pH adjustment resulted in a loss of alkalinity in the finished water and an increase in sulfur (as sulfate), whereas CO2 pretreatment preserved alkalinity in the finished water and did not increase sulfur (as sulfate).
Economic analysis for replacing residential meters
Authors: Yee Michael D. 
Published: February 2018

Statistical sampling was used to chart the degradation of water meter accuracy over time and to determine an optimal replacement age.Single‐family residential 0.6‐in. (15‐mm) meters make up about 90 percent of all meters for the Alameda County Water District in Fremont, Calif., and generate about half of all annual revenues from water consumption. Like all mechanical devices, these meters degrade in accuracy over time, resulting in an increasing amount of lost revenue. To increase meter accuracy requires replacing meters at an additional cost. The optimal economic replacement age is when the average cost per year (cumulative lost revenue plus replacement cost divided by meter age) is at a minimum. Statistical sampling was used to profile the degradation of these meters' accuracy over time. The annual lost revenue over time was then calculated. When economic and operational factors were considered, the optimal age at which to replace residential meters in the district was determined to be 15 years.