| 摘要 |
PURPOSE:To purify ozone-treated water by natural purification even after the water is discharged and contribute for environmental preservation by removing trihalomethane precursors by carrying out ozone-treatment in specified ozone consumption condition for secondary effluent obtained by precipitation treatment and activated sludge treatment. CONSTITUTION:Ozone-treatment is carried out in an ozone contacting tank in a condition of ozone consumption of 0.1-0.75mgO3/mgDOC for secondary effluent to remove trihalomethane precursors, wherein the secondary effluent is obtained by carrying out primary treatment consisting of mainly precipitation treatment and secondary treatment consisting of mainly activated sludge treatment for object water to be treated. In this way, by carrying out ozone-treatment for the secondary effluent, biological insoluble substances and remaining organic substances dissolved in the secondary effluent are decomposed and problems of byproducts produced at the time of chlorine- treatment for the secondarily treated water can be solved. By converting the biological and hardly decomposable organic substances into biological and decomposable organic substances with the specified amount of the ozone consumption, purification treatment by natural purification can be carried out for the treated water even after the water is discharged. |
