BIOLOGICAL FILTRATION DEVICE AND CLEANING OF FLOATING FILTER MEDIUM FOR BIOLOGICAL FILTRATION

摘要

PURPOSE:To increase the filtration treatment capacity and miniaturize a filtration treatment device by cleaning a floating filter medium for a biological filtration device efficiently using a small amount of backwash water. CONSTITUTION:A water collecting pipe 2 and an air dispersion pipe 3 are provided on the bottom of a filtration tank 1 and a water spraying pipe 4 is provided on the top of the filtration tank. At the same time, the filtration tank 1 is filled with a floating filter medium 6 for biological filtration with a grain size of 2 to 15mm and a specific gravity of 1 or less. In addition, a retaining element 5 for the biological filter medium which retains the floating filter medium when a waste water is discharged from the tank, is arranged in the intermediate part of the filtration tank.