METHOD OF CLEANING FILTER MEDIUM

摘要

PROBLEM TO BE SOLVED: To provide a method of cleaning a filter medium by which it becomes possible to maintain high water permeation rate for a long period of time, in the operation for a solid-liquid separation using a dynamic layer. SOLUTION: The method of cleaning the filter medium comprises intermittently stopping filtering and subjecting the filter medium to air cleaning using an air spraying pipe attached to the lower part of the filter element so as to remove excessively accumulated dynamic layer from the filter medium when solid-liquid separation for filtering an activated sludge-biological treatment liquid by a dynamic layer of the activated sludge formed on the filter medium is operated. Therein, back washing is carried out by intermittently allowing pressure water of 0.1 to 1 MPa to act at least two times to the filter medium from the permeation side toward the raw water side of the filter medium using a cleaning water storage pressure tank.