| 摘要 |
<p>PURPOSE:To reduce the quantity of washing liquid and waste water when washing a floating filter medium. CONSTITUTION:In a method for washing a floating filter medium 1 in a treating tank of a water treating and filtering device, a process in which the position of the surface of the water 10 in the tank is adjusted so as to be lower than that of the lower surface of an upper spill preventive means 2, a process in which air or the like is fed for washing, and a process in which, after the supply of air or the like is stopped, water is discharged so that the position of the surface of the water 10 may be lowered by the value smaller than the thickness of a floating filter layer 8 are provided.</p> |
