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Assessment Of Chloramine And Chlorine Residual Decay In The Distribution System
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Book Synopsis Assessment of Chloramine and Chlorine Residual Decay in the Distribution System by : Zaid K. Chowdhury
Download or read book Assessment of Chloramine and Chlorine Residual Decay in the Distribution System written by Zaid K. Chowdhury and published by IWA Publishing. This book was released on 2007-03-01 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Maintaining chlorine and chloramine residual is a key factor that determines potability of distributed water. Decay of these disinfectants is affected by various water quality and infrastructure related factors. Understanding the decay of residuals in the distribution system is critical with respect to safe delivery of drinking water and in developing water quality models that can be used by utilities for the operation of potable water delivery systems. In order to comply with microbial and disinfection byproduct (M/DBP) regulations, water suppliers are continually investing in treatment processes for achieving greater levels of inactivation and DBP precursor removal. As a result of these changes in water quality, maintaining a disinfectant residual in the distribution system can be challenging Bench-scale testing has been used to determine the effect of advanced treatment (enhanced coagulation, granular activated carbon adsorption, ozonation, biofiltration, and ultraviolet irradiation) on chlorine and chloramine decay. Additional studies examine the effects of disinfectant dose, temperature, pH, blending, and rechlorination. The effects of water quality on pipe-wall demand were evaluated using the distribution system simulator at the U.S. Environmental Protection Agency's Test and Evaluation Center. Several models are developed regarding disinfectant decay, making it easier to predict chlorine demand after changes in treatment. The multi-species water quality analysis and network path analysis extensions to EPANET will make the modeling package more robust and will allow utilities to predict chlorine residual at any point in their distribution system with greater confidence.
Book Synopsis Characterization and Modeling of Chlorine Decay in Distribution Systems by : John J. Vasconcelos
Download or read book Characterization and Modeling of Chlorine Decay in Distribution Systems written by John J. Vasconcelos and published by American Water Works Association. This book was released on 1996 with total page 440 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Maintaining Distribution System Residuals Through Booster Chlorination by : James G. Uber
Download or read book Maintaining Distribution System Residuals Through Booster Chlorination written by James G. Uber and published by IWA Publishing (International Water Assoc). This book was released on 2004 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: The goal of this project was to discuss the potential advantages associated with booster disinfection, the kinetics of chlorine decay and trihalomethane (THM) formation under rechlorination conditions, and the use of network hydraulic and water quality models to locate booster disinfection stations and determine their dose characteristics. The following are highlights from the research: A laboratory procedure was proposed for analyzing chlorine decay under simulated booster conditions. An initial set of experiments evaluated disinfectant decay under booster conditions, and found it to be dependent on both the magnitude and time of the boost dose. THM formation under booster conditions showed no long-term reduction for any set of results, indicating THM formation is not solely dependent on disinfectant concentration. In booster chloramination, boosting with chlorine appeared to be very successful at producing and maintaining a low ammonia concentration by recombining with the ammonia formed from chloramine decay. A second-order model, including a reaction component that represents natural organic matter, was developed to describe chlorine decay and THM formation under booster conditions. A method was developed to determine good locations and schedules for multiple booster doses by a systematic evaluation of alternative designs using network models. By exploring the disinfection decay kinetics under rechlorination, and developing methods for booster chlorination systems design, the project results will assist utilities and consultants in making better use of booster disinfection as a residual maintenance approach. Originally published by AwwaRF for its subscribers in 2003
Author :Gregory J. Kirmeyer Publisher :American Water Works Association ISBN 13 :9781583213315 Total Pages :278 pages Book Rating :4.2/5 (133 download)
Book Synopsis Optimizing Chloramine Treatment by : Gregory J. Kirmeyer
Download or read book Optimizing Chloramine Treatment written by Gregory J. Kirmeyer and published by American Water Works Association. This book was released on 2004 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt: This manual recommends optimal operational criteria for chloramine application to enhance and protect distribution system water quality. It examines the chemical characteristics of chloramines, documents the use of chloramines with case studies, and provides planning, design, startup, and monitoring strategies for optimizing the use of chloramines.
Book Synopsis Modeling Vulnerability and Effectiveness of Chlorination in Drinking Water Distribution Systems by : Refet Sinem Atgin
Download or read book Modeling Vulnerability and Effectiveness of Chlorination in Drinking Water Distribution Systems written by Refet Sinem Atgin and published by . This book was released on 2008 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt: Residual chlorines are provided in water distribution systems to maintain the inactivation of pathogens intruded into network. The effectiveness of chlorine residuals on pathogen removal can be determined using system vulnerability assessment. The effectiveness of chlorination was determined separately and it was determined as higher than that of the distribution and dilution for two case networks studied. CT (Chlorine Residual Concentration x Contact Time) value which is used as an important criterion to assess the inactivation of pathogens, is complicated to be determined for distribution networks due to varying residence times and chlorine concentrations. The relation of CT value with the removal ratio of pathogens was used to estimate CT value for distribution networks. The results of case studies indicate that CT value determined for a distribution network does not only depend on concentration and contact time of chlorine residuals but also temperature, pH and intrusion location and duration.
Book Synopsis Modeling Free Chlorine and Chloramine Decay in a Pilot Distribution System by : Jorge M. Arevalo
Download or read book Modeling Free Chlorine and Chloramine Decay in a Pilot Distribution System written by Jorge M. Arevalo and published by . This book was released on 2007 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt: Small diameter pipes and higher temperatures increase the rate of chlorine decay irrespective of pipe material. Additional experiments were conducted to evaluate the effect of flow velocity on chloramine decay in a pilot distribution system (PDS) for different pipe materials and water qualities. The experiments were done using the single material lines and the flow velocity of the water was varied to obtain Reynolds' numbers from 50 to 8000. A subset of experiments included the addition of blended orthophosphate corrosion inhibitor (BOP) at a dose of 1.0 mg/L as P to evaluate the effect of the inhibitor on chloramine decay. The effect of Reynolds' number on the overall chloramine decay rate (K) and the wall decay rate constant (W) was assessed for PVC, LCI, UCI, and G pipes. PVC and LCI showed no change on the rate of chloramine decay at any flow velocity. UCI and G pipes showed a rapid increase on the wall decay rate under laminar conditions (Re [less than] 500) followed by a more gradual increase under fully turbulent flow conditions (Re [greater than] 2000). The use of the BOP inhibitor did not have an effect on the rate of chloramine decay for any of the pipe materials studied. Linear correlations were developed to adjust the rate of chloramine decay at the pipe wall for UCI and G depending on the Reynolds' number.
Book Synopsis Drinking Water Distribution Systems by : National Research Council
Download or read book Drinking Water Distribution Systems written by National Research Council and published by National Academies Press. This book was released on 2007-01-22 with total page 405 pages. Available in PDF, EPUB and Kindle. Book excerpt: Protecting and maintaining water distributions systems is crucial to ensuring high quality drinking water. Distribution systems-consisting of pipes, pumps, valves, storage tanks, reservoirs, meters, fittings, and other hydraulic appurtenances-carry drinking water from a centralized treatment plant or well supplies to consumers' taps. Spanning almost 1 million miles in the United States, distribution systems represent the vast majority of physical infrastructure for water supplies, and thus constitute the primary management challenge from both an operational and public health standpoint. Recent data on waterborne disease outbreaks suggest that distribution systems remain a source of contamination that has yet to be fully addressed. This report evaluates approaches for risk characterization and recent data, and it identifies a variety of strategies that could be considered to reduce the risks posed by water-quality deteriorating events in distribution systems. Particular attention is given to backflow events via cross connections, the potential for contamination of the distribution system during construction and repair activities, maintenance of storage facilities, and the role of premise plumbing in public health risk. The report also identifies advances in detection, monitoring and modeling, analytical methods, and research and development opportunities that will enable the water supply industry to further reduce risks associated with drinking water distribution systems.
Author :Gregory W. Harrington Publisher :American Water Works Association ISBN 13 :9781583212837 Total Pages :152 pages Book Rating :4.2/5 (128 download)
Book Synopsis Ammonia from Chloramine Decay by : Gregory W. Harrington
Download or read book Ammonia from Chloramine Decay written by Gregory W. Harrington and published by American Water Works Association. This book was released on 2003 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt: This research report focused on the evaluation of the effects of pH on the inactivation of AOB by chloramines and effects of NOM removal and pH on the rate of ammonia release from the chloramine decay. It was found that water utilities should consider employing pretreatment practices that achieve great stability of chloramine residuals. in order to offset the expenses of periodic strategies to deal with nitrification. Other alternatives to consider for nitrification control are advanced NOM removal strategies or alternative pH values for water entering the distribution system.
Author :IARC Working Group on the Evaluation of Carcinogenic Risks to Humans Publisher :IARC ISBN 13 :9789283212843 Total Pages :540 pages Book Rating :4.2/5 (128 download)
Book Synopsis Some Drinking-water Disinfectants and Contaminants, Including Arsenic by : IARC Working Group on the Evaluation of Carcinogenic Risks to Humans
Download or read book Some Drinking-water Disinfectants and Contaminants, Including Arsenic written by IARC Working Group on the Evaluation of Carcinogenic Risks to Humans and published by IARC. This book was released on 2004 with total page 540 pages. Available in PDF, EPUB and Kindle. Book excerpt: A working group of 23 experts from 13 countries met in Lyon to evaluate the evidence for carcinogenicity of arsenic (mostly naturally occurring) as a contaminant of drinking-water, and of the water-disinfectant chloramine. The working group also evaluated or re-evaluated four chlorination by-products found in drinking-water, namely chloral hydrate, di- and trichloroacetic acids, and 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (also known as MX). High-level exposure to arsenic in drinking-water occurs in some regions such as China, Latin America, Bangladesh and West Bengal. The Working Group reviewed epidemiological studies of human cancer (mainly ecological studies in Taiwan and Chile, and several case-control and cohort studies) in relation to arsenic in drinking-water. Arsenic in drinking-water (primarily inorganic, as arsenate and to a lesser extent arsenite) was evaluated as carcinogenic to humans (Group 1) on the basis of sufficient evidence for an increased risk for cancer of the urinary bladder, lung and skin. Studies on inorganic arsenic in experimental animals provided limited evidence for its carcinogenicity, but sufficient evidence was found in experimental animals for the carcinogenicity of dimethylarsinic acid (an organic form of arsenic), which produced urinary bladder tumours in rats and lung tumours in mice after oral administration.
Book Synopsis Chloramine Effects on Distribution System Materials by : Steve Harold Reiber
Download or read book Chloramine Effects on Distribution System Materials written by Steve Harold Reiber and published by American Water Works Association. This book was released on 1993 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Development of a Chlorine Decay and Trihalomethane Formation Modeling Protocol Using Initial Distribution System Evaluation Data by : James P. Cooper
Download or read book Development of a Chlorine Decay and Trihalomethane Formation Modeling Protocol Using Initial Distribution System Evaluation Data written by James P. Cooper and published by . This book was released on 2009 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recently many water distribution systems (WDS) developed and calibrated extended period simulation model to assist in the Initial Distribution System Evaluation (IDSE). The IDSE is the first phase of the Stage 2 Disinfectants and Disinfection Byproducts (D/DBP) Rule promulgated by the United States Environmental Protection Agency (USEPA). The purpose of the IDSE was to identify locations within the WDS for Stage 2 D/DBP compliance monitoring. This research aided two northern Ohio distribution systems in completion of the IDSE requirements and further develops the models to predict chlorine residuals and trihalomethane (THM) concentrations.Existing models were utilized as a base and updated with data collected during extensive field studies. A Form 4: Modeling Study Plan, which provides justification that the models meet minimum calibration requirements was submitted and approved by the USEPA. The updated models were utilized to select Stage 2 D/DBP future monitoring locations. Drafts of Form 5: IDSE Report for a Modeling SSS were completed for each system.First-order reaction expressions were developed to estimate the effects of bulk reactions and reactions occurring along the surface of the distribution system pipes (wall) for free chlorine decay and THM formation. Most reaction expressions that utilize a global wall reaction rate coefficient in units of inverse time do not accurately represent the proportion of reactions occurring along the wall. As a chemical travels through a pipe, wall reactions within larger diameter pipes will have less of an effect on the overall reaction than when flowing through a smaller diameter pipe. This is because the ratio of the pipe surface to a unit volume of water is not constant throughout the distribution system. This is, however, constant given a specific flow path from the point of entry into the distribution system to any fixed point, such as a sampling location. In order to account for this wall reaction variability, a series of flow path diameter fractions are employed within the chlorine decay and THM formation expressions. A probabilistic approach using Bayesian statistics is then utilized to estimate the bulk and wall reaction coefficients. The flow path specific expressions better predicted actual data.
Author :Richard Louis Valentine Publisher :American Water Works Association ISBN 13 :0898679451 Total Pages :174 pages Book Rating :4.8/5 (986 download)
Book Synopsis Chloramine Decomposition in Distribution System and Model Waters by : Richard Louis Valentine
Download or read book Chloramine Decomposition in Distribution System and Model Waters written by Richard Louis Valentine and published by American Water Works Association. This book was released on 1998 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Water Chlorine (residual) No. 1 by : Raymond J. Lishka
Download or read book Water Chlorine (residual) No. 1 written by Raymond J. Lishka and published by . This book was released on 1969 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Analysis of Bacterial Growth in Madison Water System by : Soumya Srinivasan
Download or read book Analysis of Bacterial Growth in Madison Water System written by Soumya Srinivasan and published by . This book was released on 2004 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Predictive Models for Water Quality in Distribution Systems by : J. Clement
Download or read book Predictive Models for Water Quality in Distribution Systems written by J. Clement and published by American Water Works Association. This book was released on 2005-04-30 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt: There are two groups of specialists involved in the development and application of water quality models, each of which have a different perspective on the use of models: Academics and scientists - chemistry specialists and microbiologists who develop the models. Practitioners - modelers and distribution engineers who use them to solve problems. There are limitations and constraints in the characterization of the underlying processes and the practical application of models to distribution networks, which require further research. The objectives of the research were to characterize the current state of predictive distribution system water quality models and to identify critical research needs for their improvement. The project reviewed both the development and application of models. The report is intended to both steer future research and to act as a general reference on water quality modeling. The report combines a literature review with the practical experience of the project team. The content of a draft report was discussed at an international workshop attended by academics, engineers, scientists, and hydraulic modelers with the objective of agreeing on specific research needs necessary to improve predictive modeling for water quality in distribution systems. The conclusions of the report are derived from the workshop and form the basis of 11 specific research briefs that have been submitted to AwwaRF for consideration of funding. Researchers often focus on modeling the individual processes that control water quality rather than fully modeling water quality throughout distribution systems. For these "process models" to be applied to real distribution networks, they need to be extended to take in account the physical characteristics of the system?the special and temporal variations in flow, velocity and water age, and the effects of mixing water that has traveled along different flow paths.
Book Synopsis Investigation of Factors Affecting Chloramine Stability in the City of Arlington's Water Distribution System by : Srinivas Prabakar
Download or read book Investigation of Factors Affecting Chloramine Stability in the City of Arlington's Water Distribution System written by Srinivas Prabakar and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In this research four studies were conducted to investigate monochloramine stability in a water distribution system. The primary objective of the COA distribution study was to investigate and identify factors causing chloramine decay using data collected from the distribution system several times during the year and to generate a mathematical model of the decay. Sampling was done 3 times in the year 2009 and 2 times in the year 2010. Sampling data was analyzed by multiple regression analysis. Based on a multiple regression analysis, only pressure plane, total chlorine, and interactions of these two factors were significant in explaining total chlorine decay. The impact of pressure plane can be explained by the differences in the raw water. It was not possible to measure monochloramine decay but since monochloramine and total chlorine are significantly correlated it is likely that analysis of monochloramine decay would yield similar results. In the second study, the standard method for assimilable organic carbon (AOC) determination was compared to different methods; differential DOC by 20 days, 3 days, flow cytometry method using natural microbial consortium and by using pure culture. For 36 different samples, AOC values were found to be significantly different using the standard method and the proposed modified standard method using flow cytometry but they were well correlated (R2=0.96). AOC values by flow cytometry were on average 17.6% higher than those measured by the standard method. Flow cytometer enumeration reduces the time needed to perform the enumeration from 5 days to 1 hr which reduces the overall time required for the determination from 14 days to 9 days. Also, flow cytometer enumeration gives the flexibility to store the samples for the efficient use of the flow cytometer. The third study investigated the impact of pre-ozonation, intermediate ozonation, coagulation-floculation-sedimentation, biofiltration and chloramination on AOC concentration. From this study it is found that the pre-ozonation and intermediate ozonation increased the AOC concentrations. Pre-ozonation increased AOC concentration higher than intermediate ozonation and chloramination. The coagulation flocculation, and sedimentation processes and the biofiltration process reduced the AOC concentration from pre-ozonation and intermediate ozonation. Surprisingly, coagulation, flocculation, and sedimentation reduced AOC more than bio-filtration. In the fourth study the monochloramine decay rate was studied as a function of temperature, initial concentration of biofilm, pH and AOC, each at two levels in the treated drinking water. Linear regression and ANOVA analysis were used for the investigation. From linear regression monochloramine decay and total chlorine decay were found to better fit a second order rate than zero or first order for the majority of treatments. The coefficient of determination, R2, for the monochloramine decay data from sixteen treatments fit with a second order reaction varied between 0.84 and 0.99. From ANOVA analysis it is found that presence of biofilm increased the monochloramine decay. Increased AOC increased the monochloramine decay in the longer water age while temperature and pH were not found to be significant factors. Total chlorine decay results were similar to monochloramine decay.
Book Synopsis Computer Simulation and Analysis of Chlorine Decay in a Water Distribution Network System with Two Different Concentrations by : Thomas Bardawil
Download or read book Computer Simulation and Analysis of Chlorine Decay in a Water Distribution Network System with Two Different Concentrations written by Thomas Bardawil and published by . This book was released on 1994 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
