| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a backwashing method which can remove pollutants from a biological activated carbon layer with a relatively small amount of backwashing water sufficiently reduce the final turbidity of the backwashing water, and sufficiently keep high washing efficiency over a long period of time even in the case that an existing treatment tank is converted to the biological activated carbon treatment apparatus. SOLUTION: This backwashing method for the biological activated carbon treatment comprises a first concurrently washing process where backwashing with air is carried out at the same time backwashing with the backwashing water is carried out at a flow rate which makes the coefficient of cubic expansion of the biological activated carbon layer 20% or higher to fluidize the biological activated carbon layer. A second concurrently washing process where backwashing with air is carried out and at the same time backwashing with the backwashing water having a flow rate lower than that of the first concurrently washing process is carried out to make the polluting matter adhered to the biological activated carbon layer and floated in the backwashing water, and a backwashing water discharge process where backwashing with water is carried out and at the same time the pollutants floated in the backwashing water during the second concurrently washing process are discharged together with the backwashing water.</p> |
