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Real–time monitoring and computerization for microbial inactivation using C ÷ T
Author(s) -
Schneider Lewis,
Billings Charles
Publication year - 2007
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.1551-8833.2007.tb08059.x
Subject(s) - disinfectant , interim , sampling (signal processing) , setpoint , environmental science , surface water , log reduction , operations management , environmental engineering , chemistry , computer science , engineering , artificial intelligence , telecommunications , geography , food science , archaeology , organic chemistry , detector
With promulgation of the Surface Water Treatment Rule (SWTR), the Interim Enhanced SWTR, and subsequent guidance, surface water treatment plants were charged with legally meeting C ÷ T levels (disinfectant concentration times detention time) for microbial inactivation. Compliance eventually required segmenting C ÷ T calculations and a disinfection profile as a compilation of the daily Giardia log inactivations. Criteria needed to determine microbial inactivation included flow, contact (detention) time, free chlorine residual, pH, and temperature. From this set of criteria, a C ÷ T could be calculated. This article describes how a large surface water treatment plant, the North Jersey District Water Supply Commission, grappled with and solved the challenge of C ÷ T implementation. Through effective management, leadership, and planning, the utility successfully moved from an initial approach of grab sampling and spreadsheet determinations to online instrumentation and eventual computerization of the program into the supervisory control and data acquisition system.