To enable a reduction of a usage rate of a chlorine agent for preventing recontamination of treated water, and inhibition of the recontamination of treated water.
A water treatment method comprises a process (21) for injecting metal ions (12) and hydrogen peroxide (11) to water to be treated and oxidatively decomposing organic substances in the water to be treated by radicals generated by Fenton reaction between the metal ion and hydrogen peroxide, and a process (22) for injecting bubbles of ozone (5, 13) to the water to be treated discharged from the above process and oxidatively decomposing organic substances to generate treated water. The injection rate of ozone is adjusted so as to maintain the ozone concentration of the treated water after a set time at a set value or higher, which reduces the usage rate of the chlorine agent for preventing the recontamination of the treated water, and inhibits the recontamination of the treated water.
ENBUTSU ICHIRO
WATANABE SHOJI
HIDAKA MASATAKA
SUMIKURA MISAKI
HARA NAOKI
