1. The valves on the access pipeline shall be fully opened to make the load of each filter pond be equal.
2. Flushing : Each filter pond shall be forced-flushed once in a day, the operation is as follows:
Open the forced-flushing water valve, close the anti-siphon valve, close the forced-flushing valve after the siphon is formed for flushing.Align the conical baffle to make the flushing time within 5 to 7 min. The backflushing intensity shall be controlled to the maximum flow when the fine sand can not run out.  After flushing, open the anti-siphon valve for operation.