| 摘要 |
PROBLEM TO BE SOLVED: To easily separate and recover powdery photocatalysts without using a membrane, to permanently reutilize the separated photocatalysts and to remarkably reduce the cost required for a light source. SOLUTION: In this method, raw water 11 is subjected to light irradiation treatment in a photoreaction process 1 coexisting the powdery photocatalysts with iron hydroxide fine particles or aluminum hydroxide fine particles, then is subjected to solid-liquid separation and the separated sludge is circulated to the photoreaction process 1, and the separated water 13 is subjected to biological treatment by a biological membrane under an aerobic condition, or to biological treatment by the biological membrane after the photoreaction process 1. A part of biologically treated water 14 is circulated to the photoreaction process 1, and the remaining biologically treated water is subjected to flocculation and the separated sludge 15 is circulated to the photoreaction process 1. |
