Controlling disinfection by-products within a distribution system through bubble aeration

Disinfection by-product (DBP) formation within drinking water distribution systems is an inevitable circumstance due to reactions between residual chlorine and carry-over organic matter from the treatment process. However, regulated DBPs must be maintained below the maximum containment levels. Distribution systems are operated, in part, with by-product formation in mind, albeit development exceeding growth, increased water age, changes in water demand, and tighter water quality regulations can compromise a utility's ability to meet water quality regulations. While many water quality models exist that predict formation and removal of disinfectant by-products, no models have been applied to a distribution system model to explore system-wide impacts when employing a trihalomethane (THM) control strategy from within storage tanks, such as aeration. This work utilizes a first-order model to represent the removal of THMs through the use of fine bubble aeration within a storage tank. The model parameters were estimated using laboratory-scale experimental data and were shown to adequately estimate observed conditions within an actual storage tank employing fine bubble aeration. The resulting model was used to determine the system-wide impact of in-tank aeration as a THM removal strategy. Overall, the aeration system was shown to have a significant impact on THM concentrations throughout the system, particularly in regions impacted by the aerated storage tank.