| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent the inflow of sludge particles (SS) to the secondary side of a filter during washing the filter. SOLUTION: When a filtration layer on the surface of a filter 3 is peeled off by supplying gas from a vent pipe installed below the filter 3, raw water in a water tank 6 is supplied to the secondary side of the filter 3 by a water supply pump 8, a water supply tank 9, and a water sending pipe 10. The entrance of SS is prevented by supplying clean water to the secondary side of the filter 3 during washing operation. When filtration operation is restarted, since SS entered the secondary side is diluted with the clean water, the deterioration in the quality of treated water is reduced. The pollution of the primary and secondary sides is prevented simultaneously so that stable, effective biotreatment can be continued over a long period.</p> |
