bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ion exchange softening: effects on metal concentrations
Authors: Sorg Thomas J. , Schock Michael R. , Lytle Darren A. 
Published: February 2018

Leaching data from a two‐phase study indicate that ion exchange softening does not systematically increase metal concentrations.A corrosion control pipe loop study was conducted to evaluate the effect of ion exchange water softening on metal leaching from household plumbing materials. The two water sources evaluated had different pH values and hardness levels. Results showed that removing hardness ions with a household water softener did not lead to a pattern of higher metal leaching from various home plumbing materials containing lead, copper, and zinc. Furthermore, the water softener did not have a detrimental effect on several significant water quality parameters that influence metallic solubility and the rate of corrosion, i.e., pH, total inorganic carbon, dissolved oxygen, chlorine, temperature, and orthophosphate.
Determining GAC bed life
Authors: Gillogly Thomas E.T. , Snoeyink Vernon L. , Vogel John C. , Wilson Claude M. , Royal Earl P. 
Published: February 2018

Laboratory columns closely simulated the performance of a pilot plant for taste and odor control.This study developed a way to rapidly and effectively evaluate the remaining life of a granular activated carbon (GAC) bed used to mitigate taste and odor episodes. The maximum attenuation of a 2‐methylisoborneol (MIB) episode, a representative taste and odor compound, can rapidly be determined using laboratory‐scale columns packed with partially spent GAC taken from full‐scale operating adsorbers. These laboratory‐scale columns closely simulated the performance of pilot‐scale columns. The percent of a transient MIB load removed by GAC did not depend on the influent MIB concentration but did depend on the amount of natural organic matter adsorbed on the GAC surface. This approach can be used to determine GAC's potential percentage removal of taste‐ and odor‐causing compounds as a function of GAC service time. It allows GAC to be tested to estimate its readiness for summer taste and odor episodes. Adsorption alone in GAC adsorbers that used < 10 min of empty bed contact time was insufficient to fully protect against typical MIB episodes.
Assessing ozone disinfection with nonbiological surrogates
Authors: Mariñas Benito J. , Rennecker Jason L. , Teefy Susan , Rice Eugene W. 
Published: February 2018

Fluorescent‐dyed polystyrene microspheres can be used to assess disinfection efficiency.The authors investigated the use of fluorescent‐dyed polystyrene microspheres to assess drinking water disinfection efficiency in full‐scale ozone contactors. A demonstration was conducted with one of two parallel full‐scale ozone bubble‐diffuser contactors at the Alameda County Water District Water Treatment Plant in Fremont, Calif. Microsphere suspensions were analyzed by flow cytometry to determine changes in fluorescence distribution. Selection of threshold fluorescence intensities allowed the determination of microsphere “survival” ratios that were correlated with Cryptosporidium parvum inactivation curves. Compared with the concentration times contact time (C X T) concept, use of the surrogate indicators offered a potentially simpler and more accurate approach for assessing and optimizing ozone disinfection efficiency achieved in full‐scale contactors and for demonstrating compliance with disinfection requirements.
Committee Report: Emerging pathogens—viruses, protozoa, and algal toxins
Authors:   AWWA Research Division Microbiological Contaminants Research Committee
Published: February 2018

Water utility managers will need to know important issues about microbes of concern in drinking water.The American Water Works Association Research Division Microbial Contaminant Committee reviewed three viral and three protozoan microorganisms and one set of bacterial toxins of greatest concern to the water industry: enterovirus, calicivirus and Norwalk virus, and hepatitis; Cyclospora cayetanensis, microsporidia, and Toxoplasma gondii; and cyanobacterial toxins. To help the water quality specialist, this report describes the virus, protozoan, or toxin; reviews its health effects; summarizes information on its occurrence, waterborne outbreaks, and water treatment; discusses analytical procedures; and outlines needed research.
Microbiological quality before and after nanofiltration
Authors: Laurent Patrick , Servais Pierre , Gatel Dominique , Randon Guy , Bonne Pascal , Cavard Jacques 
Published: February 2018

A long‐term study identifies the benefits accrued when a distribution system fed with biologically treated water switches to a nanofiltered supply.The authors investigated microbiological behavior of a distribution system supplied initially with biologically treated water and then with nanofiltered water. Their purpose was to identify and evaluate the changes in microbiological water quality attributable to modifications in water treatment at the plant. During the course of the study, all data from various indicators of microbiological quality (i.e., heterotrophic plate counts, coliform enumeration, total direct counts, and fixed bacterial biomass) showed similar trends. Results indicated that the use of nanofiltration allows utilities to reduce chlorination of treated water and at least maintain or increase the microbiological quality of distributed water for areas with high residence times.
Using ion chromatography to detect perchlorate
Authors: Okamoto Howard S. , Rishi Dharmendra K. , Steeber William R. , Baumann Frank J. , Perera S. Kusum 
Published: February 2018

Ion chromatography with suppressed conductivity was used to develop the California Department of Health Services trace concentration method for perchlorate analysis.This article describes an ion chromatography method to analyze trace concentrations of perchlorate in drinking water. Perchlorate was separated from anions commonly found in groundwater and surface water by elution through an AS5 anion exchange column with 120 mmol/L sodium hydroxide + 2 mmol/L ρ‐cyanophenol. Analytes were measured by conductometric detection using signals enhanced by chemical suppression of the conductance from the eluent. A 740‐μL sample injection provided the sample mass necessary to achieve a perchlorate method detection limit of ≤ 1 μg/L and a working range of 2.5–100 μg/L, without sample preconcentration. Interference studies showed that 5.0 μg/L of perchlorate could be measured in the presence of 1,000 mg/L of bicarbonate, chloride, or sulfate. The method was successfully used to survey drinking water wells in California considered vulnerable to perchlorate contamination.
Combined arsenic and nitrate removal by ion exchange
Authors: Ghurye Ganesh L. , Clifford Dennis A. , Tripp Anthony R. 
Published: February 2018

If an MCL < 5 μg/L is adopted for arsenic, then many suppliers will need to treat water specifically to remove it.On‐site ion exchange studies investigated the combined removal of arsenic (V) [As(V)] and nitrate from drinking water in McFarland and Hanford, Calif., and Albuquerque, N.M. Whereas previous ion exchange workers had studied removal of high concentrations of As (> 50 μg/L As) without nitrate present, these studies focused on removing 10–15 μg/L As to achieve a product water with < 2 μg/L As while also maintaining nitrate below its maximum contaminant level. Results of 1‐in.‐ (25‐mm‐) column experiments showed that conventional sulfate‐selective resins were better than special nitrate‐selective resins for combined As(V) and nitrate removal. The conventional resins yielded longer run lengths and leaked less As and nitrate into the product water. Decreasing empty bed contact time from 3.0 to 1.5 min did not greatly alter As leakage into the product water. Particulate iron in the ion exchange feed increased As leakage in the product water. Two commercially available computer programs were reasonably accurate in predicting both As and nitrate run lengths for various influent nitrate and sulfate concentrations. Generally, predicted As and nitrate run lengths were within ±35 percent of those observed experimentally.
Conscientious particle counting
Authors: Van Gelder Annika M. , Chowdhury Zaid K. , Lawler Desmond F. 
Published: February 2018

The water industry needs to develop concentration standards that will enable it to assess the accuracy of particle counts taken by different instruments.Research was undertaken to test whether different particle counters yield the same particle count and size distribution information, to assess the possibility of using particle concentration standards from other applications in the water industry, and to develop and test a concentration standard for use in the water industry. Five particle counters were used, including duplicates of each of two manufacturers' light‐obscuration instruments (commonly used in the water industry) and one electrical sensing zone (ESZ) instrument. On all types of samples (latex spheres, a commercially available fine test dust used as a standard in other industries, and water treatment plant samples), the light‐obscuration instruments consistently measured far fewer particles in the smallest sizes (2–5 μm) than the ESZ instrument, and evidence is presented that suggests the ESZ instrument is more correct. Recommendations for standards to use with light‐obscuration instruments include using a multimodal count standard using latex spheres of two sizes, with those sizes being in the middle of standardized size ranges; using separate sizing standards at the boundaries of the size ranges; and avoiding any use of particle counters for regulatory purposes at this time.
Regulations in 2000 and beyond
Authors: Pontius Frederick W. 
Published: February 2018

Water‐related rules are reviewed to help utilities plan strategically and achieve compliance within required time frames.To meet the demands of future regulations, water utilities will need to anticipate and strategically plan for future regulatory requirements. Regulatory trends for 2000 and beyond are reviewed so that water utilities may achieve compliance within required time frames. This article is Journal AWWA's annual review of the US Environmental Protection Agency's drinking water regulatory agenda under the Safe Drinking Water Act.
Effects of UV irradiation on organic matter
Authors: Shaw Jeffrey P. , Malley James P. , Willoughby Susan A. 
Published: February 2018

Many paired t‐tests showed—at a 95 percent confidence level—no evidence that UV treatment increased BDOC or AOC.The effects of low‐pressure mercury‐vapor ultraviolet (UV) irradiation at 254 nm on the biological regrowth potential of two surface water and two groundwater sources are reported. Because of possible effects of the pending Ground Water Rule, UV disinfection is being studied as an alternative to chlorination. Water samples to be tested were separated into hydrophilic and hydrophobic fractions. The concentration of biodegradable dissolved organic carbon (BDOC) was measured in nonfractionated and fractionated water samples collected before and after UV treatment at a dosage of 130 mW·s/cm2. Two methods were compared in these analyses: a 30‐day BDOC and a 5‐day assimilable organic carbon (AOC) test. Many paired t‐tests showed (at a 95 percent confidence level) no evidence that UV treatment increased BDOC or AOC. Because results differed in water from different sources, utilities considering UV treatment should evaluate the potential for biological regrowth in their own distribution systems.
Determining disinfection needs
Authors: Bellamy William , Carlson Kenneth , Pier David , Ducoste Joel , Carlson Mark 
Published: February 2018

The integrated disinfection design framework can help utilities lower disinfectant dosages and costs and minimize formation of disinfection by‐products.The integrated disinfection design framework (IDDF) is a new approach for determining disinfection requirements for a water treatment facility. The framework may be applied in place of the procedures in the US Environmental Protection Agency's Surface Water Treatment Rule guidance manual. Potential benefits include lower disinfectant dosages, reduced disinfectant costs, and reduced formation of disinfection by‐products. The feasibility of the IDDF was presented in an AWWA Research Foundation–sponsored project completed in 1998. A user‐friendly model has been developed based on the original IDDF concepts; this model allows utility personnel, consultants, and regulators to determine site‐specific disinfection requirements. The model has four components or modules: (1) hydraulic characteristics, (2) disinfectant demand–decay, (3) inactivation kinetics, and (4) disinfection by‐product formation. Implementation of the IDDF at the Aurora (Colo.) Water Department is in progress with a chlorine dioxide dosage reduction of approximately 15 percent. Other IDDF implementation studies have indicated that primary disinfectant dosages can be reduced by 8–35 percent with a corresponding reduction in disinfection by‐products.
A new process for electrocoagulation
Authors: Mills Donald 
Published: February 2018

For water providers needing to make the most of scarce resources, a new electrocoagulation system treats contaminated supplies effectively and economically.An innovative electrocoagulation process has been shown to be effective in treating raw water sources for the production of potable water. The process is a boon to water reuse because it has the capability to remove heavy metals from contaminated water streams and to treat leachates from mining and landfill sites. Study results showed bacteria (i.e., E. coli) were typically reduced by a factor of log 4.17 to concentrations below the detection limit. Molybdenum was reduced from 9.95 to 0.006 mg/L in leachate at a mining site, and iron was reduced from 130 to 0.015 mg/L in leachate from a landfill site. In the new process, coaxial electrodes permit continuous flow at rates up to 225,000 L/min (5.944 × 104 gpm) and above. The technology has no moving parts and operates at a fraction of the cost of other water treatment systems. Because the flocculent produced is chemically inert and does not leach back contaminants, it is readily disposable. In addition to describing the electrocoagulation process, the author discusses the critical role water electrolysis intermediate radicals play in removing bacteria.
DBP formation during chloramination
Authors: Diehl Alicia C. , Speitel Gerald E. , Symons James M. , Krasner Stuart W. , Hwang Cordelia J. , Barrett Sylvia E. 
Published: February 2018

Batch study results may help utilities select appropriate chloramination conditions to limit DBP formation.Batch experiments were conducted on three diverse water sources to study the formation of dissolved organic halogen (DOX), trihalomethanes (THMs), haloacetic acids (HAAs), and cyanogen halides (CNX) during chloramination. The authors used preformed chloramines to examine the effect of pH, mass ratio of chlorine to ammonia–nitrogen (Cl2 to N), and bromide concentration on disinfection by‐product (DBP) formation. Formation of specific DBPs as well as the group parameter DOX was greatest at low pH and high Cl2‐to‐N ratios and followed the general trend of decreasing with increasing pH and decreasing Cl2‐to‐N ratio. Bromide addition increased the concentration of bromine‐substituted DBPs and DOX. These experiments demonstrated that because of dihaloacetic acid formation, HAA formation is more problematic during chloramination than THM formation. Because the specific DBPs measured in this research (THMs, six HAAs, and CNX) accounted for no more than 35 percent of the DOX concentration, utilities may want to consider both specific DBPs and DOX in selecting appropriate chloramination conditions.
Accounting for lost water
Authors: Buie Leslie M. 
Published: February 2018

One county found ways to identify and reduce the amount of lost water while realizing efficiencies and cost savings.This article reports on efforts by DeKalb County (Ga.) to identify, measure, and reduce the amount of unaccounted‐for water. This information may help those with similar concerns and interests to realize that this type of effort can benefit customers. DeKalb County used methodical and logical analysis of data that reflected the county's experience as well as applied guidance from other studies and research to resolve the issue of unaccounted‐for water.
Adding PAC to remove DOC
Authors: Campos Carlos , Schimmoller Larry , Mariñas Benito J. , Snoeyink Vernon L. , Baudin Isabelle , Laîné Jean‐Michel 
Published: February 2018

An upflow floc blanket reactor installed upstream of ultrafiltration membranes assists adsorption of dissolved organic carbon.The hybrid process resulting from adding powdered activated carbon (PAC) to ultrafiltration (UF) reactors is being used to remove organic compounds in full‐scale drinking water treatment plants. One way to increase the adsorption efficiency of PAC is to add it to continuously stirred tank reactors (CSTRs) or to plug flow reactors installed upstream of the membranes. Additionally, the PAC that is recovered from the membrane backwash can be recycled to a floc blanket reactor (FBR) installed upstream of the PAC/CSTR–UF process. This study developed an adsorption model that predicts the removal of dissolved organic carbon (DOC) in the FBR–PAC/CSTR–UF system. The model was verified experimentally using two commercially available PACs in a laboratory‐scale pilot unit. Removal of DOC by coagulation with aluminum salts and adsorption on the recycled PAC in the FBR substantially reduced carbon use. The model was used to assess the effect of various operating parameters on DOC adsorption efficiency and to determine optimal operating conditions.
Evaluating TOC analytical results
Authors: Najm Issam , Marcinko Joseph , Oppenheimer Joan 
Published: February 2018

Tests indicate particulate fraction of total organic carbon in a natural water is more accurately measured by the combustion method than by the ultraviolet–persulfate oxidation method.The Disinfectants/Disinfection By‐products (D/DBP) Rule includes total organic carbon (TOC) as a regulatory compliance parameter with the idea that TOC concentration is a direct indicator of the potential for DBP formation upon chlorination. A comprehensive study was conducted to evaluate the ability of the two most common methods—ultraviolet (UV)–persulfate oxidation and catalytic combustion—to measure the particulate fraction of the TOC in water and determine whether this fraction contributes to DBP formation. Results showed that particulate TOC fraction in a natural water was more accurately measured by the combustion method. Therefore, the method used by a water utility to evaluate TOC removal through a water treatment plant can significantly affect the chemical dosages required for regulatory compliance and treatment cost. Furthermore, chlorination testing results suggest that the DBP formation reactions may not be affected by particulate TOC, leading the authors to propose that dissolved organic carbon rather than TOC is a more appropriate indicator of DBP formation potential in water treatment.
Using UV to inactivate Cryptosporidium
Authors: Clancy Jennifer L. , Bukhari Zia , Hargy Thomas M. , Bolton James R. , Dussert Bertrand W. , Marshall Marilyn M. 
Published: February 2018

Even extremely low dosages of ultraviolet light can be highly effective for inactivating Cryptosporidium oocysts.Recent studies have shown that Cryptosporidium parvum oocysts demonstrate high susceptibility to low dosages of medium‐pressure ultraviolet (UV) light. These investigations have raised several questions, which include determination of minimum medium‐pressure UV dosages necessary to inactivate C. parvum oocysts, elucidation of differences (if any) between medium‐ and low‐pressure UV light for inactivating C. parvum oocysts, and evaluation of medium‐pressure UV effectiveness in inactivating oocysts suspended in poorer quality water. To compare low‐ and medium‐pressure UV, the authors exposed oocysts suspended in deionized water to UV delivered by either medium‐ or low‐pressure UV lamps at bench scale using a collimated beam apparatus. The applied UV dosages ranged from 3 to 33 mJ/cm2, and oocyst inactivation was assessed using the neonatal mouse infectivity assay. At 3 mJ/cm2, medium‐pressure UV showed a 3.4‐log inactivation of oocysts, and low‐pressure UV showed a 3.0‐log inactivation, demonstrating medium‐ and low‐pressure UV did not differ significantly in inactivating C. parvum oocysts.
Building a better protozoa data set
Authors: Connell Kevin , Rodgers Crystal C. , Shank‐Givens Heather L. , Scheller Jennifer , Pope Misty L. , Miller Ken 
Published: February 2018

Comparisons of ICR and ICRSS data indicate the Supplemental Surveys' improved methodology and procedures yield more accurate data on protozoa occurrence.The Information Collection Rule Supplemental Surveys (ICRSS) were designed to supplement the ICR with more reliable information on protozoa occurrence. The surveys benefitted from measures that were not part of the ICR, notably an improved protozoa detection method, an expanded quality control (QC) program, and a centralized sample control center. Based on analyses of data from the protozoa monitoring portion, the ICRSS have yielded measurable improvements in the quality of protozoa occurrence data available to support current rulemaking efforts. Compared with ICR results, ICRSS field sample data are characterized by higher detection rates and fewer potential false‐positive results. Data from more than 400 source water QC samples analyzed during the surveys indicated mean Cryptosporidium recoveries of 43 percent and mean Giardia recoveries of 53 percent from field samples spiked with laboratory strains of these organisms. Results confirmed that the performance of methods 1622 and 1623 during monitoring of 87 US source waters was consistent with their anticipated performance, demonstrated through interlaboratory validation studies conducted before surveys began.
Multiarm‐polyethylene glycol‐polyglutamic acid peptide dendrimer: Design, synthesis, and dissolving thrombus
Authors: Zhang Shao‐Fei , Lü Shaoyu , Gao Chunmei , Yang Jiandong , Yan Xiang , Li Tao , Wen Na , Huang Mengjie , Liu Mingzhu 
Published: February 2018

AbstractThrombotic events affect many individuals in a number of ways, all of which can cause significant morbidity and mortality. Nattokinase (NK), as a novel thrombolytic drug, has been used for thrombolytic therapy. It not only possesses plasminogen activator activity, but also directly digests fibrin through limited proteolysis. However, it may undergo inactivation and denaturation in the harsh external environment. In this study, a multiarm‐polyethylene glycol‐polyglutamic acid peptide dendrimer was fabricated and used as a carrier for NK protection and delivery. Different arm numbers of polyethylene glycol‐polyglutamic acid peptide dendrimers (x‐PEG(G3)x, x = 2, 4, 6, 8) were designed, prepared, and characterized by 1 H NMR and FTIR. Then, x‐PEG(G3)x were loaded with NK to form nanocomposites. Their size and morphology were determined by dynamic light scattering and transmission electron microscopy. Enzyme activity was evaluated via UV–Vis absorbance spectra, fluorescence spectra, circular dichroism spectra, and zeta potential measurements. The study reveals that the obtained x‐PEG(G3)x/NK nanocomposites possess high enzyme activity. In addition, the nanocomposites show increased viability of rat macrophage cells, and excellent thrombolysis ability in vitro and in vivo. This work establishes a multiarm‐polyethylene glycol‐polyglutamic acid peptide dendrimer with potential application in NK carrier and thrombolytic therapy. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1687–1696, 2018.