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Chlorine and Solute Transport and Reactions in Drinking Water Distribution: The Role of Flow Hydrodynamics on Water Quality Changes and Multi-Criteria Compliance
Citation:
YANG, Y. J., R. M. CLARK, AND A. D. LEVINE. Chlorine and Solute Transport and Reactions in Drinking Water Distribution: The Role of Flow Hydrodynamics on Water Quality Changes and Multi-Criteria Compliance. Chapter 9, B. Jordao and E. Sousa (ed.), Risk Management; Safety and Risk in Society Series. Nova Science Publishers, Inc, Hauppauge, NY, , ISBN: 9781608760114, (2010).
Impact/Purpose:
To inform the public.
Description:
Safe drinking water supply is one of the most notable modern engineering achievements in the 20th century. It is a centerpiece of the U.S. environmental protection effort under the federal Safe Drinking Water Act (SDWA) and its amendments. In this chapter, water quality changes are analyzed for chlorine disinfectant as a reactive solute transporting in the drinking water distribution pipes. The solute fate and transport phenomena under discussion fall into two broad categories: chlorine decay throughout a distribution network, and dispersion-reaction of “foreign” contaminants in discrete volumes. Common to the two categories are their convection dispersion-reaction (CDR) process. From here, the role of pipe flow hydrodynamics in kinetics of chlorine decay and water quality changes is reviewed in a stepwise theoretical analysis of the Dankwerts CDR model and its simplifications. The analysis is also supported by field observations reported in literature and by the testing results of controlled pilot-scale experiments. Through the analysis, complexities in chlorine’s physiochemical interactions with other solutes and pipe walls begin to emerge in light of a flow hydrodynamic field, pointing to the challenge as well as potentials to prevent excessive quality deterioration and achieve simultaneous multi criteria compliance required by the SDWA regulations. The effects of pipe flow properties (e.g., Reynolds number) on the reaction kinetics of chlorine and other solutes in water are quantified, the current state of knowledge and future research needs are identified for optimization of the water distribution process design and operations.
