Pilot Study of Greater Boston Drinking Water Quality Changes– Monochloramine and pH change

摘要

A pilot study was conducted from July 2001 to November 2003 to understand thernimpact of ozonation on monochloramine decay and pH change in the futurernMassachusetts Water Resources Authority’s (MWRA1) drinking water system. Thernimpact of the distribution system, which consists of old cast-iron pipes, was alsorninvestigated.rnHomogeneous and heterogeneous samples were taken from the Pipe Loop Pilot Plantrn(PLPP), which represented the best and the worst scenarios respectively, I.e. a veryrnclean distribution system, or dead ends far from the main.rnThe results suggested that corrosion and biological activity inside the pipe were thernmajor causes of the deteriorated water quality in heterogeneous samples. Inrnhomogeneous samples, ozonation may cause faster monochloramine decay and largerrndecrease of pH. Therefore more chemicals may be needed for pH adjustment andrnresidual disinfectant when the new Walnut Hill Water Treatment Plant (WHWTP) isrnonline.