Calibration of Chlorine Decay Rates by a Combined Optimization Algorithm

Accurate prediction of chlorine residue concentration has become one of the most important tools for water quality modeling and management in water distribution systems. Although former researchers used genetic algorithm (GA) solver to calibrate relative parameters, it was found difficult to apply this method in large-scale water distribution systems due to its long computational time. In this paper, the chlorine decay rates in the wall reactions within the pipes are calibrated dynamically by a new combined optimization algorithm of CORS-RBF-GA. The CORS-RBF-GA algorithm takes CORS (Constrained Optimization using Response Surface) as the whole optimization framework, RBF (Radial Basis Function) as a surrogate of the water quality detailed model, GA as RBF optimization solver. The computational time of water quality modeling and simulation of water networks is reduced four times. One engineering case study is also presented for testifying this method, followed with more efficient and promising results of chlorine residue simulations, comparing with the field measurements.