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Analyzing Disinfection Kinetics and Reactor Design: A Conceptual Approach Versus the SWTR
Author(s) -
Lawler Desmond F.,
Singer Philip C.
Publication year - 1993
Publication title -
journal ‐ american water works association
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.466
H-Index - 74
eISSN - 1551-8833
pISSN - 0003-150X
DOI - 10.1002/j.1551-8833.1993.tb06103.x
Subject(s) - effluent , disinfectant , dimensionless quantity , water disinfection , chemistry , chlorine , kinetics , pulp and paper industry , process engineering , environmental engineering , waste management , thermodynamics , environmental science , nuclear engineering , engineering , physics , organic chemistry , quantum mechanics
The Surface Water Treatment Rule (SWTK) specifies C x T values for achieving various degrees of inactivation of pathogenic microorganisms, with C being the concentration of the disinfectant in the effluent from any reactor and T being a characteristic contact time dependent on reactor hydraulics. The disinfection credit calculated for reactors using the SWTR‐prescribed C x T approach is compared with predictions based on accepted disinfection kinetics and fundamental reactor behavior. This analysis demonstrates that the C x T approach lacks a sound conceptual basis, tends to be somewhat conservative, and is unnecessarily costly for many water treatment plants. A dimensionless parameter, k' Cθ , the product of a disinfection rate constant, the effluent disinfectant concentration, and the theoretical detention time, provides a systematic approach for evaluating disinfection conditions and plant modifications. The decay of chlorine in the reactor is considered, and an error in a previous J ournal article is corrected.