| 摘要 |
The present invention provides a backwashing method for a filtration device that has a simple structure and enables adequate backwashing. Raw water flows down through a filtration column (1) comprising filter material layers (3, 4). If the filtration differential pressure rises, air-backwashing, water/air-backwashing and water-backwashing are carried out. When water/air-backwashing is carried out, an air-bleed valve (7), a water-bleed valve (13), a backwashing water intake valve (19), and an air intake valve (21) are opened, backwashing water and air are supplied into the filtration column (1), the filtration material layers (3, 4) are stretched out, and adhered material which has adhered to the filtration material is removed therefrom. The discharge water from water/air-backwashing flows out from a water-bleed pipe (12). |
