AWWA CSC94001

Maintaining a safe residual chlorine concentration level with a minimum quantity of chlorine is more severely required after the water quality standards were amended. But it is difficult to control chlorine dose rates when ammonia concentration increases suddenly in raw water. It is also difficult to measure chlorine demand online over a long period of time. This paper reports an investigation on feed forward chlorine dose control, which adjusts a gain following chlorine consumption calculated by 2nd order model with lag time, to solve the problem wherein chlorine demand cannot be measured exactly due to dirt and coexistent amines. The developed control was installed, and good response was achieved during sudden ammonia concentration increase.