Combined chlorine dissipation: Pipe material water quality, and hydraulic effects

摘要

Free chlorine is the disinfectant most widely used by utilities to ensure microbial safety throughout drinking water distribution systems. Free chlorine decay kinetics and pathways are well established as a result of the long history of free chlorine use. Promulgation of the Stage 2 Disinfectants/Disinfection Byproducts Rule in the United States forced many utilities to switch to combined chlorine. The conversion to combined chlorine poses many challenges, including understanding all relevant combined chlorine reaction pathways and kinetics. This knowledge is especially important for modeling purposes, an important tool for predicting and maintaining distribution system disinfectant residual.