Examination of Disinfectant Residual Decay and Organochloramine Formation in Drinking Water Distribution Systems

点击翻译按钮获取中文摘要

Disinfectants such as chlorine or chloramine are added to treated drinking water prior to entering a distribution system to protect against pathogen intrusion, biological regrowth and to ultimately ensure that consumer's receive safe water. Due to the potential extended periods of time that water spends in a distribution system and associated interactions with pipe materials, water quality often changes from when it leaves a treatment plant to when it is consumed. The Town of Newmarket has experienced issues maintaining a sufficient disinfectant residual throughout their distribution system, which has led to costly maintenance activities and accelerated their pipeline replacement. To-date, more than $1-million has been spent to mitigate this issue. Mechanisms responsible for disinfectant decay must be better understood such that effective remediation plans may be developed.The proposed research will examine the decay and speciation of disinfectant residual in the Newmarket distribution system as a function of water chemistry, pipewall interactions, temperature and hydraulic conditions. To facilitate this research, the Drinking Water Research Group at the University of Toronto has designed pipe section reactors that are capable of replicating distribution system conditions such that these issues may be evaluated under controlled conditions in a lab. To validate and confirm results pipe section reactors will be operated in parallel to pipeloop systems which will be continuously fed with water from the distribution system. Application of this methodology will allow us to identify specific mechanisms responsible for accelerated monochloramine decay in distribution systems and to ultimately provide guidance for future operation and maintenance activities.