WATER PURIFICATION APPARATUS

PURPOSE:To supply the treated water of an invariably good quality to users by obtaining chemical supply amount from the results of measurement of untreated water quality at a water purification plant and projected water intake value and computing chemical supply timing taking into account the lag of the chemical arrival time behind the water arrival time to control a chemical supply facility. CONSTITUTION:A part of untreated water sent in a water intake 1 is introduced to a water quality meter 2 on the water intake side to measure the water quality. The water quality data thus obtains is fed into a computor 5 to obtain the amount of chemical to be supplied to a water purification plant 6. The water quality data regarding the plant 6 after the chemical supply is obtained by a water quality meter 13 and fed into the computor 5. This computor 5 computes the chemical supply timing taking into account a projected water intake value and a lag of the time taken for the chemical to reach the plant 6 from a chemical supply facility 12 behind the time taken for the water to reach the plant 6 from the water intake 1. An instruction of the chemical supply control at such timing is given to the facility 12 through a PIO 14.