Aqua Pennsylvania (Aqua PA), an Aqua America subsidiary, serves more than 1.4 million people in 32 counties across Pennsylvania. Aqua PA has significant experience using chloramine chemistry to mitigate trihalomethane (THM) disinfection byproduct formation in its many distribution systems. As with most water utilities, this traditionally meant constant monitoring and unplanned operator callouts to adjust influential water storage tank disinfectant residual levels, particularly in the summer.
After Pennsylvania published its Disinfectant Requirements Rule (DRR) in April 2018, utilities were required in most cases to maintain a minimum chlorine residual of 0.20 mg/l at the point of use (in a home, for example). Leading up to the DRR’s promulgation, Aqua PA had been considering deploying a residual control system that could automatically maintain chloramine residuals and positively influence downstream network water quality.