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Development Of A Chlorine Decay And Trihalomethane Formation Modeling Protocol Using Initial Distribution System Evaluation Data
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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.
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
Book Synopsis Development of Exposure Assessment Methods for THM and HAA in Water Distribution Systems by : Jay Nuckols
Download or read book Development of Exposure Assessment Methods for THM and HAA in Water Distribution Systems written by Jay Nuckols and published by American Water Works Association. This book was released on 2001 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chlorination is commonly used by water utilities in the United States and around the world for the disinfection of public water supplies. Over the last 25 years, epidemiological research has provided mounting evidence of a possible link between by-products of the chlorination process and the incidence of colorectal, bladder, and brain cancer. This volume resents the results of a study on exposure assessment methods for two of these disinfection by-products (DBPs)--trihalomethanes (THMs) and haloacetic acids (HAAs). The volume is not indexed. c. Book News Inc.
Book Synopsis The Management of Trihalomethanes in Water Supply Systems Preferred Access Arrangement by : Daniel Brown
Download or read book The Management of Trihalomethanes in Water Supply Systems Preferred Access Arrangement written by Daniel Brown and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The formation of potentially harmful trihalomethanes (THM) when using chlorine as a disinfectant in potable water supplies has led to tighter regulatory controls and hence a need for better models for THM management. The prediction of THM concentration is difficult due to the complex and changing hydrodynamic and chemical regimes found in water treatment works (WTWs) and distribution systems. The purpose of the study is to increase understanding of THM formation and chlorine decay through six water treatment works (WTWs) and distribution systems operated by Severn Trent Water Ltd and ultimately develop an efficient, robust, cost effective model for chlorine decay and THM formation. With knowledge of the bulk chlorine decay characteristics and the THM productivity of the water, this model offers a simple and straightforward tool which can be readily applied to WTWs and distribution systems alike to provide an initial assessment of the risks of total THM formation at different sites, and to identify sites and systems at risk of compliance failure. Relying only on the measurement of analytically undemanding parameters (in particular, chlorine and its decay with time), under appropriate circumstances this model offers advantages of simplicity and cost-effectiveness over other, more complex models. The model can thus be applied to assess the chemical risk under different scenarios allowing for informed decision making.
Book Synopsis The Management of Trihalomethanes in Water Supply Systems Preferred Access Arrangement by :
Download or read book The Management of Trihalomethanes in Water Supply Systems Preferred Access Arrangement written by and published by . This book was released on with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The formation of potentially harmful trihalomethanes (THM) when using chlorine as a disinfectant in potable water supplies has led to tighter regulatory controls and hence a need for better models for THM management. The prediction of THM concentration is difficult due to the complex and changing hydrodynamic and chemical regimes found in water treatment works (WTWs) and distribution systems. The purpose of the study is to increase understanding of THM formation and chlorine decay through six water treatment works (WTWs) and distribution systems operated by Severn Trent Water Ltd and ultimately develop an efficient, robust, cost effective model for chlorine decay and THM formation. With knowledge of the bulk chlorine decay characteristics and the THM productivity of the water, this model offers a simple and straightforward tool which can be readily applied to WTWs and distribution systems alike to provide an initial assessment of the risks of total THM formation at different sites, and to identify sites and systems at risk of compliance failure. Relying only on the measurement of analytically undemanding parameters (in particular, chlorine and its decay with time), under appropriate circumstances this model offers advantages of simplicity and cost-effectiveness over other, more complex models. The model can thus be applied to assess the chemical risk under different scenarios allowing for informed decision making.
Book Synopsis Modeling Water Age and Disinfection Byproduct Formation in Drinking Water Distribution Systems in East Tennessee by : Seth Adam Fischer
Download or read book Modeling Water Age and Disinfection Byproduct Formation in Drinking Water Distribution Systems in East Tennessee written by Seth Adam Fischer and published by . This book was released on 2015 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chlorine disinfection of drinking waters is responsible for the standard of health we enjoy today and the eradication of waterborne disease. Chlorine also reacts with natural organic matter (NOM) to form disinfection byproducts (DBPs) which have been linked to cancer as well as reproductive and developmental issues. The exact mechanism for formation of regulated DBPs, trihalomethanes (THMs) and haloacetic acids (HAAs), is unknown. The literature has identified relationships between DBP formation and, most notably, characteristics of NOM, chlorine contact time, temperature, pH [negative log of hydrogen ion concentration], and chlorine dose. This study develops models both specific to individual utilities, and general to utilities with surface water sources using NaClO [sodium hypochlorite] for disinfection within the geographic region of East Tennessee. The study utilizes existing data from four utilities collected for compliance with regulations. Calibrated hydraulic models of the four distribution systems are employed to accurately determine water age (chlorine contact time) in the distribution system, often a limitation of field scale models. Multivariate power functions predict THMs and HAAs for individual utilities and across utilities with similar raw water characteristics and treatment processes. R2 [coefficient of determination] ranges from 0.52 to 0.80. Developed models account for actual distribution system conditions, including water age, and predict THM and HAA levels for the four utilities with a higher R2 value than applicable existing lab scale and field scale models. Results arm utilities with strategies to develop specific DBP models using existing data, control DBP levels, improve quality of drinking water, and achieve compliance with regulations.
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 Water Distribution System Handbook by : Larry W. Mays
Download or read book Water Distribution System Handbook written by Larry W. Mays and published by McGraw-Hill Companies. This book was released on 2000 with total page 686 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The only book of its kind, this compendium brings you detailed coverage of the latest methods, materials, techniques, and tools for water distribution systems." "Written by top experts that are members of the American Water Works Association, the American Society of Civil Engineers, and other leading professional organizations, the Water Distribution Systems Handbook provides specialists in each area to serve as your consultants. Each chapter provides expert, detailed, professional guidance on an important aspect of water distribution systems."--BOOK JACKET.
Book Synopsis Preventing Haloform Formation in Drinking Water by : Leland L. Harms
Download or read book Preventing Haloform Formation in Drinking Water written by Leland L. Harms and published by . This book was released on 1980 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Interim Treatment Guide for the Control of Chloroform and Other Trihalomethanes by : James M. Symons
Download or read book Interim Treatment Guide for the Control of Chloroform and Other Trihalomethanes written by James M. Symons and published by . This book was released on 1976 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Treatment Techniques for Controlling Trihalomethanes in Drinking Water by : James M. Symons
Download or read book Treatment Techniques for Controlling Trihalomethanes in Drinking Water written by James M. Symons and published by . This book was released on 1981 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Modeling Chlorine Decay and Chlorination By-product Formation in Water Treatment and Distribution by : John N. McClellan
Download or read book Modeling Chlorine Decay and Chlorination By-product Formation in Water Treatment and Distribution written by John N. McClellan and published by . This book was released on 2000 with total page 638 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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.
Book Synopsis Path-dependent Approach to Estimate Chlorine Wall Demand Coeffcient in Water Distribution System by :
Download or read book Path-dependent Approach to Estimate Chlorine Wall Demand Coeffcient in Water Distribution System written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A novel approach to calibrate pipe wall demand coefficients for chlorine decay using an input-output model framework is proposed. The input-output model of water quality in water distribution system developed in this research is presented as a particle (water parcel) backtracking algorithm, which provides information that is not available using traditional simulation approaches: the various paths that water takes between a particular input source and output node, and their associated time delays and impact on output node water quality. Such information constitutes a complete description of the input-output behavior under typical assumption of first-order chemical decay or production reactions. Therefore the chlorine concentration at "downstream" locations can be expressed explicitly as a function of concentration at "upstream" locations, and pipe wall demand coefficients. This not only expedites the computational efficiency of the parameter estimation algorithm, but frees the field study to consider chlorine concentration sampling at any location in a network. Chlorine measurement and hydraulic model errors will cause uncertainty in wall demand coefficient estimates and this should be taken into consideration in sampling design. In this research, sensitivity-based method is developed to select chlorine measurement locations for the purpose of getting reliableestimates of wall demand coefficients. The impact of hydraulic error on wall demand coefficient estimation of different designs is compared using a heuristic representing the sensitivity of modeled chlorine concentration to hydraulic error. Chlorine measurement errors are also considered and a D-optimal design algorithm is applied to select chlorine measurement locations. This proposed approach is suboptimal, yet efficient and practical, and considers both hydraulic and chlorine measurement errors. A field study is conducted in a southern U.S. utility as an application of the parameter estimation approach. A tracer study is implemented and the conductivity measurements are used to calibrate an existing hydraulic model through a manual approach. Chlorine concentrations are monitored continuously both at water source and within the distribution system. The wall demand coefficient is calibrated, assuming all pipes have the same demand coefficient.
Book Synopsis New Orleans Area Water Supply Study by : Southeast Environmental Research Laboratory. Analytical Chemistry Branch
Download or read book New Orleans Area Water Supply Study written by Southeast Environmental Research Laboratory. Analytical Chemistry Branch and published by . This book was released on 1974 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Modeling Trihalomethane Formation Potential from Wastewater Chlorination by :
Download or read book Modeling Trihalomethane Formation Potential from Wastewater Chlorination written by and published by . This book was released on 1994 with total page 97 pages. Available in PDF, EPUB and Kindle. Book excerpt: The deletion of federally mandated fecal coliform limits has led many states to review and modify their wastewater disinfection requirements. One issue in analyzing wastewater disinfection is the discharge of potentially carcinogenic halogenated organics formed during the chlorination process. This research investigates the formation of one class of the halogenated organics, the trihalomethanes. The applicability of using drinking water trihalomethane formation models for use with wastewater effluent is examined. Three models are compared for predictive capability by using measured trihalomethane values from previous research data. The results show that a previously developed model is applicable for use based on assumptions stated. Results provide environmental managers with worst case predictions for a range of wastewater treatment plant (WWTP) parameters. Predictions indicate that trihalomethane formation from the chlorination of wastewater is typically lower than the Safe Drinking Water Act trihalomethane standard of 100 ug/L. The worst case model predictions reach, and in certain extreme cases, pass the standard of 100 ug/L. This level of trihalomethanes formed is minimized if aeration of the receiving bodies of water occurs. Based on this research, the risk of forming trihalomethanes as disinfection by-products from chlorination do not outweigh the benefits gained from proper chlorine disinfection of effluent. Wastewater, Wastewater disinfection by-product modeling, Trihalomethanes chlorination by-products, Chemical modeling.
