| 摘要 |
PROBLEM TO BE SOLVED: To eliminate a need of chlorine and a flocculating agent by mixing/dispersing a gaseous ozone in the raw water into fine bubbles having an average bubble size less than a specified value as a pretreatment, introducing the mixture to a lower part of a reaction tank and bringing the bubbles into contact with the raw water to react with it to form an insoluble flocculated matter. SOLUTION: A suspended matter and a floated matter are removed from a raw water 101 to be treated, and the water is stored in a raw water storage tank 105 and sent to a mixer 110 by a water pump 107. The gaseous ozone 113 is generated at an ozone generator 115 and injected to the mixer 110. At this time, the average bubble size of the gaseous ozone is kept in <=300 μm. Then, the raw water to be treated and the gaseous ozone are mixed in the mixer 110. The raw water 118 to be treated discharged from the mixer 110 is introduced to the lower part side surface of the reaction tank 120 together with a large amount of the fine dispersed bubbles of gaseous ozonized oxygen. In this case, the fine dispersed bubbles and the raw water are subjected to a contact reaction by raising the bubbles and the water in parallel flow to form an insoluble flocculated matter. Then the raw water to be treated is passed through a liq. filter 140 to filter and remove the flocculated matter. |
