An Optimum Approach to Effluent Disinfection

The City of Kansas City, Missouri received modifications to the Blue River Wastewater treatment plant discharge permit requiring implementation of disinfection by December 31, 2013. The Blue River plant is a 150 mgd Trickling Filter plant that serves the eastern part of the Kansas City Metropolitan area. Studies were conducted that indicated that disinfection using sodium hypochlorite and dechlorination using sodium bisulfite would be the most effective approach for disinfection at this facility. As part of disinfection improvements at the Blue River Wastewater treatment, the City examined several approaches for reducing capital and operating costs. These approaches included onsite generation, onsite generation over the fence, truck delivery of 12.5 percent Sodium hypochlorite and rail delivery of 20 percent sodium hypochlorite. Onsite generation over the fence would have the generation equipment located near the treatment plant, but operated by a contract operator. Typically, railcar delivery would not be considered, however availablity of high strength 20 percent sodium hypochlorite provided a cost reduction in transportation cost with minimum degradation of the chlorine. A design that allowed for 20 percent delivery of hypochlorite by railcar or over the fence, and 12.5 percent delivery by truck was ultimately selected by the City for implementation at this facility.