bluuebunny/crossref_metadata_2025_split huggingface dataset:
Arsenic removal by ferric chloride
Authors: Hering Janet G. , Chen Pen‐Yuan , Wilkie Jennifer A. , Elimelech Menachem , Liang Sun 
Published: February 2018

Source water composition affects removal efficiency.Bench‐scale studies were conducted in model freshwater systems to investigate how various parameters affected arsenic removal during coagulation with ferric chloride and arsenic adsorption onto preformed hydrous ferric oxide. Parameters included arsenic oxidation state and initial concentration, coagulant dosage or adsorbent concentration, pH, and the presence of co‐occurring inorganic solutes. Comparison of coagulation and adsorption experiments and of experimental results with predictions based on surface complexation modeling demonstrated that adsorption is an important (though not the sole) mechanism governing arsenic removal during coagulation. Under comparable conditions, better removal was observed with arsenic(V) [As(V)] than with arsenic(III) [As(III)] in both coagulation and adsorption experiments. Below neutral pH values, As(III) removal–adsorption was significantly decreased in the presence of sulfate, whereas only a slight decrease in As(V) removal–adsorption was observed. At high pH, removal–adsorption of As(V) was increased in the presence of calcium. Removal of As(V) during coagulation with ferric chloride is both more efficient and less sensitive than that of As(III) to variations in source water composition.
Cost of membrane softening in Florida
Authors: Bergman Robert A. 
Published: February 2018

Membrane treatment cost data based on actual plant operations provide an easy way to estimate order‐of‐magnitude costs for membrane systems.Costs for membrane softening plants in Florida with capacities from 1 to 14 mgd (3.8 to 53 ML/d) are presented. Costs for installed membrane system, water treatment plant construction, operation and maintenance, and total treated water production are included based on data from the author's survey of operating membrane softening plants. Unit cost curves are included as a function of installed membrane permeate capacity. The effects of membrane bypass and blending, plant operating factors, concentrate disposal, and amortization at various interest rates are discussed.
An introduction to epidemiology
Authors: Craun Gunther F. , Calderon Rebecca L. , Frost Floyd J. 
Published: February 2018

Epidemiology is a complex and subtle science that is being applied increasingly to disease outbreaks caused by drinking water contaminants.Epidemiologists study the occurrence and causes of disease in human populations and apply this knowledge to the prevention and control of health problems. Studies are increasingly being conducted to determine health risks that may be associated with environmental exposures, especially from drinking water. This article will help drinking water professionals become more familiar with the terminology, types of studies that can be conducted, sources of possible bias, and some of the reasons why results can be controversial.
US outbreaks of cryptosporidiosis
Authors: Solo‐Gabriele Helena , Neumeister Shondra 
Published: February 2018

An overview of US cryptosporidiosis outbreaks suggests that conventional treatment processes operated at minimum regulatory compliance levels are ineffective at preventing transmission of the disease.Drinking water has been implicated as the mode of transmission in several outbreaks of cryptosporidiosis throughout the United States. This review of US outbreaks describes characteristics of the raw water supply, suspected sources of contamination, water treatment methods, and corrective actions. Of the total number of outbreaks, roughly half were associated with groundwater sources; the majority of affected individuals, however, were served by drinking water drawn from surface water. Wastewater was implicated as the source of contamination of raw or treated water for roughly half of the outbreaks. Nonpoint sources, such as agricultural runoff, were suspected sources of contamination in the remaining outbreaks. The majority of affected individuals were served by treatment plants using coagulant addition, filtration, and chlorine disinfection processes. Although treatment deficiencies and suboptimal operational practices were noted during some of the outbreaks, all treatment plants were complying with federal and local regulations. Existing regulations and water supply systems, especially those utilizing surface water sources, should be reevaluated.
Environmental methods for Cryptosporidium
Authors: Jakubowski Walter , Boutros Susan , Faber Walter , Fayer Ron , Ghiorse William , LeChevallier Mark , Rose Joan , Schaub Stephen , Singh Ajaib , Stewart Mic 
Published: February 2018

A number of approaches offer promise for addressing the limitations of current antibody‐based detection methods.This report was prepared by the Working Group on Waterborne Cryptosporidiosis (Technical Task Force E, Developmental Status of Environmental Sampling, Water Testing, and Surrogate Indicators). Methods for detecting Cryptosporidium oocysts in water have centered around microscopic examination of fluorescent antibody‐stained concentrates from large‐volume water samples. The limitations of these antibody‐based methods include the need for experienced analysts, lengthy analytical time, expense, lack of specificity, erratic efficiency, low precision, and difficulty in determining viability. A number of methods, assays, and procedures that have the potential for ameliorating some of these limitations are currently being evaluated. How successful such processes will be remains to be demonstrated by the scientific community.
Bromate ion removal by HEEB irradiation
Authors: Siddiqui Mohamed S. , Amy Gary L. , Cooper William J. , Kurucz Charles N. , Waite Thomas D. , Nickelsen Michael G. 
Published: February 2018

High‐energy electron‐beam irradiation removes bromate after its formation, when other control strategies are not as effective.Proposed drinking water regulations will specify a maximum contaminant level of 0.01 mg/L for bromate ion (BrO3−). This study used high‐energy electron‐beam irradiation to remove BrO3− after formation, when other control strategies are not as effective. BrO3− was reduced to bromide ion (Br−), with bromine (HOBr/OBr−) as intermediate. A dose of 60 krads was sufficient to reduce 70 percent of BrO3− from an initial concentration of 100 μg/L. The presence of electron scavengers such as hydrogen peroxide and nitrate significantly reduced BrO3− removal, whereas the addition of the OH radical scavenger such as t‐butanol did not affect the removal of BrO3−. This indicates that aqueous electrons (eaq−) are mainly responsible for BrO3− destruction. The presence of natural organic matter decreased BrO3− reduction efficiency. The reaction of eaq− with various bromine species in water was used to model and simulate experimental data for the destruction of BrO3−. Computer model predictions were in fairly good agreement with the experimental results.
Iron oxide adsorption and UF to remove NOM and control fouling
Authors: Chang Yujung , Benjamin Mark M. 
Published: February 2018

Addition of iron oxide particles to a UF system can significantly increase NOM removal efficiency, slowing membrane fouling.This study applied a novel single‐fiber membrane module to study fouling of ultrafiltration (UF) membranes by natural organic matter (NOM) molecules, and used a combined iron oxide–UF process to reduce that fouling. Addition of iron oxide particles to a UF system can significantly increase NOM removal efficiency, because NOM molecules that would otherwise pass through the membrane sorb to the oxides and are retained. Furthermore, despite the fact that iron oxide particles cannot selectively adsorb foulant molecules, their presence in the system can reduce the membrane fouling dramatically. This effect is mediated through two processes: a decrease in the NOM concentration in the circulation loop because of sorption and the formation of iron oxide cake layer deposits on the membrane surface. In such a system, the condensed layer of NOM forms on top of the cake, protecting the underlying membrane surface.
Business planning for small system capacity development
Authors: Cromwell John E. , Rubin Scott J. , Marrocco Frederick A. , Leevan Mark E. 
Published: February 2018

Business planning will help small systems harness the power of local informed self‐interest, identify communities that need extra help, and support state and local government efforts to enhance incentives and remove barriers to possible improvements.Pennsylvania began developing a statewide strategy to address viability of small water systems in 1990. The authors have been continuously involved in this process. Many pieces of the program are in place and provide a foundation for meeting capacity development and affordability provisions of the 1996 Safe Drinking Water Act amendments.
Improving service to small communities
Authors: MacDonald Jacqueline A. , Zander Amy K. , Snoeyink Vernon L. 
Published: February 2018

The National Research Council suggests a strategy that dovetails with three key provisions of the 1996 SDWA amendments.The National Research Council recently published a report calling for a three‐part strategy to improve the quality of water service in small communities. The strategy, outlined in this article, involves improving the sustainability of financing and management of small water systems, enhancing the training of small system operators, and reducing duplication of costly pilot testing efforts for small system technologies. These steps correlate to key provisions of the 1996 Safe Drinking Water Act amendments and should assist the US Environmental Protection Agency, states, and water utilities with implementing those amendments.
Predicting As removal during metal hydroxide precipitation
Authors: McNeill Laurie S. , Edwards Marc 
Published: February 2018

Data from two utility surveys led to the development of a simple model for predicting arsenate removal at full‐scale alum coagulation, ferric coagulation, and iron–manganese removal plants.A simplified isotherm is described that can predict the extent of arsenate removal at drinking water utilities practicing coagulation or iron–manganese (Fe–Mn) removal. If all possible sources of particulate iron and aluminum hydroxide present in the system are accounted for, the model predicts arsenic (As) removal to within ±13 percent (90 percent confidence) for Fe coagulation at pH 6.5–8 and alum coagulation at pH < 7.6. Analysis of full‐scale treatment data suggests that colloidal aluminum (Al) flocs with sorbed arsenate [As(V)] may pass through filters, thereby decreasing overall As removal efficiency. Thus, Al solubility and particle stability must be minimized to improve As removal. If stability and solubility of aluminum hydroxide flocs are not a problem, alum and Fe coagulants have nearly equal capacity for sorbing As(V). Survey results also demonstrate the importance of particulate As.
Ozonation and BDOC removal: effect on water quality
Authors: Cipparone Lori A. , Diehl Alicia C. , Speitel Gerald E. 
Published: February 2018

Batch experiments indicate biological treatment improves overall water quality and reduces biological regrowth.Batch experiments were conducted to determine the effect of several ozone dosages and biological treatment on a surface water. Total organic carbon (TOC) concentration, chlorine demand, bacterial regrowth, and disinfection by‐product (DBP) formation were measured after ozonation and after subsequent biodegradation. TOC removal increased with ozone dosage, but the extent of removal from biodegradation alone leveled out after an ozone dose of 1 mg O3/mg TOC. Chlorine demand reduction was highly correlated with the TOC removal, and chlorine residuals were maintained significantly longer in ozonated and biologically treated water, compared with water treated with ozone alone. Biological organic carbon removal delayed bacterial regrowth in chlorinated water, and DBP formation was reduced for ozone doses at or below 3 mg O3/mg TOC. Although higher chlorine residuals were maintained in the biologically treated water, higher DBP concentrations were not produced, indicating that biological treatment reduced DBP precursor levels.
Evaluation of optical detection methods for waterborne suspensions
Authors: Sethi Virendra , Patnaik Priyamvada , Biswas Pratim , Clark Robert M. , Rice Eugene W. 
Published: February 2018

Making design criteria for turbidimeters more stringent would enable an integrated approach to turbidity measurement and particle detection.Turbidimeters and optical particle counters (OPCs) are used to monitor particulate matter in water. The response from these instruments is governed by the optical properties of the suspension and the instrument design. The recommended design criteria for turbidimeters allow for large tolerances that lead to variations in measurements from different instruments. OPCs provide size‐specific information but may inaccurately size microorganisms or particles having optical properties different from those of the calibration particles. The authors evaluate the effects of optical design parameters in turbidimeters and OPCs. Performance data from two OPCs are presented. A multiple‐angle light‐scattering method was developed to obtain “optical signatures” from suspensions of monodisperse spheres and several microorganism isolates. Such “signatures” provide more optical information on waterborne particles and may also be used to identify specific types of microorganisms in real time.
Predicting liquid bleach decomposition
Authors: Gordon Gilbert , Adam Luke C. , Bubnis Bernard P. , Kuo Ching , Cushing Robert S. , Sakaji Richard H. 
Published: February 2018

A hypochlorite ion degradation model helps utilities using liquid bleach to develop control strategies to minimize formation of chlorate ion.Studies have led to an understanding of how chlorate ion (ClO3–) formation in the pH 6–13 region from decomposing bleach is affected by pH, temperature, NaOCl concentration, chloride ion concentration (by means of an ionic strength effect), and transition metal ion impurities. The hypochlorite ion degradation model developed by Gordon and Adam predicts free available chlorine decomposition, ClO3– formation, and oxygen generation. Thus, a utility applying liquid bleach can use this newly developed model to predict the time‐dependent changes that occur in stored liquid bleach and to develop chemical specifications and control strategies to minimize the formation of ClO3– during the storage of sodium hypochlorite. The field studies reported here provide verification of the model showing a strong correlation between the model predictions and the measured data taken in the field.
Optimizing treatment through Fe and Mn fractionation
Authors: Carlson Kenneth H. , Knocke William R. , Gertig Kevin R. 
Published: February 2018

Application of Fe and Mn fractionation procedures helps improve finished water at three treatment facilities.A series of filtration steps was used to separate iron (Fe) and manganese (Mn) into soluble, colloidal, and particulate fractions. Two case studies demonstrate how fractionation data can improve understanding of the origins and removal of Fe and Mn. The Mn species present in one water source were shown to be regulated by a biogeochemical cycle in which the natural oxidation and reduction of Mn appeared to be microbially mediated. Mn removal was improved by adjusting the application of potassium permanganate to account for this cycle. A groundwater treatment plant was suffering from high postfilter Fe and Mn concentrations. Fractionation data identified the problem as inadequate solids capture, not oxidant dosage, allowing a quick solution. The unexpected oxidation of Mn with chlorine (Cl2) was attributed to Fe oxide surface catalysis. Without adequate particle removal (no coagulant added), applying Cl2 on top of the filters exhibited superior removal to adding Cl2 before a detention basin.
Bromate minimization during ozonation
Authors: Song Rengao , Westerhoff Paul , Minear Roger , Amy Gary 
Published: February 2018

A study of BrO3‐ and TOBr production during ozonation indicates that both can be controlled by decreasing HO· and HOBr/OBr‐ concentrations.Significant levels of both bromate (BrO3‐) and brominated organics, measured as total organic bromine (TOBr), form during ozonation of water containing bromide and natural organic matter (NOM). Ozonation of several ultrafiltration and reverse osmosis membrane NOM isolates leads to approximately 17 percent of the bromide converting to bromate and 7 percent to TOBr. Depressing pH or adding hydroxyl radical scavengers decreases BrO3‐ production but promotes TOBr formation. In the presence of NOM, hydrogen peroxide addition lowers TOBr formation and may increase or decrease BrO3‐ formation, depending on other water quality factors. Ammonia addition decreases both BrO3‐ and TOBr production. Both BrO3‐production and TOBr production decrease when the initial bromide concentration is decreased and the ratio of ozone dosage to dissolved organic carbon is lowered.
Technical note: Does hydroxyl radical oxidize bromide to bromate?
Authors: Symons James M. , Zheng Michael C.H. 
Published: February 2018

Exposing bromide ion–laden water to hydrogen peroxide and H2O2–UV‐Vis irradiation did not result in the formation of bromate ion.Although ozonation of bromide ion–containing water can produce bromate ion, studies with the hydrogen peroxide–ultraviolet‐visible irradiation (H2O2–UV‐Vis) advanced oxidation process demonstrated that this reaction did not occur when this advanced oxidation process was used. Reduction of any HOBr formed by the excess H2O2 used in this process may have prevented bromate formation.
Carboxylic acids: formation and removal in full‐scale plants
Authors: Gagnon Graham A. , Booth Stephen D.J. , Peldszus Sigrid , Mutti Dennis , Smith Franklyn , Huck Peter M. 
Published: February 2018

Carboxylic acids were formed upon ozonation but were not completely removed by biological filtration, which could have implications for bacterial regrowth in distribution systems.This article presents data on the formation and removal of carboxylic acids in a full‐scale treatment plant employing ozonation and biological filtration. Carboxylic acid concentrations increased after ozonation and decreased through subsequent filtration. Simple linear relationships between major water quality parameters (e.g., temperature, pH) and acid formation did not exist. Yields of carboxylic acids on ozonation were an order of magnitude greater than for the corresponding aldehyde. An empirical linear model could describe the removal of carboxylic acids through biological filtration from a practical point of view. However, the data suggest the removal mechanism may be complex. Although contact times in the filters were quite long (on the order of 30 min), removal of several carboxylic acids was incomplete (e.g., average effluent concentration of formate was 44 μg/L).
Protozoa in open reservoirs
Authors: LeChevallier Mark W. , Norton William D. , Atherholt Thomas B. 
Published: February 2018

Open finished water reservoirs are vulnerable to microbial contamination, but current analytical techniques do not permit assessment of the organisms' viability.The impact of storage of potable water in open reservoirs was assessed by examining inlet and effluent water samples from six open finished water reservoirs used by four New Jersey utilities. Water quality parameters investigated included Giardia cysts, Cryptosporidium oocysts, total and fecal coliforms, bacteriophage, heterotrophic plate count bacteria, turbidity, particle counts, chlorine residuals and other parameters. Fifteen percent of inlet samples and 25 percent of effluent samples contained the organisms. When data for cysts and oocysts were combined, the difference in concentrations between the inlet and effluent was statistically significant, even when results were adjusted for analytical recovery efficiency. Although the concentration of protozoa increased following open reservoir storage, the analytical method used does not permit assessment of the organisms' public health significance. Nearly all of the cysts and oocysts were empty or contained undiscernible internal structures, suggesting the health risk is low. The implication of these findings for watershed control programs is discussed.
Integrated membrane treatment in Alaska
Authors: Lozier James C. , Jones Greg , Bellamy William 
Published: February 2018

An integrated membrane system for a surface water supply in Barrow, Alaska, combines microfiltration and nanofiltration.An integrated membrane treatment process consisting of microfiltration followed by nanofiltration is producing potable water in Barrow, Alaska. The process was selected to address treatment of surface water that is cold, highly colored, of low turbidity, and relatively soft with moderate alkalinity. The water has supersaturated concentrations of dissolved gases, high concentrations of natural organic material including disinfection by‐product precursors, and significant concentrations of Giardia and Cryptosporidium. The dual‐membrane process produces finished water that exceeds current and anticipated regulatory requirements at minimal operating complexity and cost.
Effect of pretreatment on surface water nanofiltration
Authors: Chellam Shankararaman , Jacangelo Joseph G. , Bonacquisti Thomas P. , Schauer Barbara A. 
Published: February 2018

A pilot study using integrated membrane systems suggests that MF or UF pretreatment may be necessary to reduce fouling during NF of surface water.An integrated membrane system pilot study compared microfiltration (MF), ultrafiltration (UF), and conventional treatment as pretreatment strategies for surface water nanofiltration (NF) using spiral‐wound elements. MF and UF pretreatment resulted in lower NF fouling rates and longer cleaning intervals compared with those measured following conventional treatment. NF fouling rates evaluated under a wide range of hydrodynamic conditions following conventional treatment suggest NF fouling is more influenced by permeate flux than by feedwater recovery. NF was shown to be capable of meeting all current and anticipated trihalomethane and haloacetic acid regulations.
State and regional water planning in Texas
Authors: Bagwell Tony , Personett Mike 
Published: February 2018

The state water plan is an important guide for state policy‐makers, as well as regional and local water planners and managers.Because of an extreme drought during the 1950s, Texas made statewide water supply planning a policy priority. The Texas Water Development Board was created to provide organizational and financial assistance to local and regional water suppliers. Over the past 40 years this planning effort has evolved in response to a variety of changing conditions. The comprehensive Texas Water Plan, based on a consistent framework of planning data and forecasts, was developed with significant regional and local participation. The plan challenges state leaders, water managers, and the general public to take the necessary and often controversial or innovative actions to meet the state's water needs for the next 50 years in a timely, cost‐effective, and environmentally sensitive manner.
The Willamette—a river in peril
Authors: Leland David , Anderson Steven , Sterling Danold J. 
Published: February 2018

The future health of the river depends on actions taken today.The overall health of the Willamette River is slightly better than marginal. The health of the river in the future depends on action taken today: it can be maintained or improved with active effort, or it can be allowed to decline. That picture emerged from the Willamette River Basin Water Quality Study. The five‐year study adapted established study methods and water quality models to a major river system. It was funded and carried out by a combination of agencies and stakeholders.