Optimization of booster disinfection with backtracking algorithm

Booster disinfection is the reapplication of disinfectant at strategic locations within a water distribution network to keep disinfectant residuals within specified limits. Compared to conventional methods that apply disinfectant only at the source, booster disinfection could improve residual coverage, and reduce the total disinfectant dose due to the more even distribution of disinfectant in space and time. However, decisions on booster disinfection in many places were made only based on experience, causing insufficient residuals at some part of the network. The present work investigates the optimal placement of extra boosters and injection scheduling on the basis of existing locations for disinfection to insure drinking water safety for all consumers. Unlike previous models, the present model optimizes booster facility location from a hydraulic prospective instead of experience. By backtracking the upstream nodes of the residual insufficient nodes, the optimal booster locations could cover the disinfectant need for all consumers. The injection scheduling of the existing disinfection locations could also be optimized with the extra booster disinfection to minimize the total disinfection dose.