Chemical precipitation water treatment system and method for controlling dosage of chemical precipitant

The invention provides a chemical precipitation water treatment system and a method for controlling the dosage of a chemical precipitator, and relates to the technical field of water treatment. The control method comprises the following steps: injecting sewage to be treated into the simulation reactor; adding a chemical precipitant into the simulated reactor, and obtaining the turbidity relative change rate of the water body in the simulated reactor; comparing the relative change rate of the turbidity with a preset relative change rate of the turbidity, if the relative change rate of the turbidity is smaller than the preset relative change rate of the turbidity, stopping adding the chemical precipitant, and calculating the concentration of the chemical precipitant in the simulation reactor; and according to the concentration of the chemical precipitant in the simulation reactor and the amount of sewage to be treated, determining the dosage of the chemical precipitant. According to the method, whether the opti