| Understanding the efficacy of secondary disinfectants in water distribution systems has become increasingly important, as research has shown that microorganisms can survive in distribution systems despite the presence of disinfectants. Disinfectant efficacy is affected by numerous factors including pipe conditions, water age and finished water quality. The purpose of this study was to (1) develop a test apparatus to simulate water distribution systems, (2) verify the test apparatus accurately simulates a water distribution system, and (3) operate the test apparatus to correlate the interaction of the various factors (pipe material and water quality) that affect the efficacy of secondary disinfectants.; The test apparatus, the Dalhousie Pipe Loop(c), a recirculating pipe loop, was developed and set up in four field locations at four water utilities across North America.; The pipe loops operated for a period of a minimum of six months; over that period disinfectant residual and other water quality parameters were monitored. In particular, parameters that were routinely monitored at the influent and effluent of the pipe loops include turbidity, pH, Colour, alkalinity, hardness, corrosion rate, dissolved oxygen, iron, and organic content and make-up.; Selection of secondary disinfectants and distribution materials can have a large impact on the water quality delivered to the consumer and are dependent on interaction with the finished water quality. Total disinfectant residual appeared to be affected by pipe material but the relationship was dependent on the type of secondary disinfectant used. (Abstract shortened by UMI.)... |
