Recommended maintenance activities for media filters
Recommended maintenance activities for media filters (Sources: WMI, 1997; Pitt, 1997).
Activity
Schedule
If filter bed is clogged or partially clogged, manual manipulation of the surface layer of sand may be required. Remove the top few inches of media, roto-till or otherwise cultivate the surface, and replace media with like material meeting the design specifications.
Replace any filter fabric that has become clogged.
As needed
Ensure that contributing area, facility, inlets and outlets are clear of debris.
Ensure that the contributing area is stabilized and mowed, with clippings removed.
Remove trash and debris.
Check to ensure that the filter surface is not clogging (also check after storms greater than about 1”).
Ensure that activities in the drainage area minimize oil/grease and sediment entry to the system.
If permanent water level is present in pre-treatment chamber (e.g., perimeter sand filter), ensure that the chamber does not leak, and normal pool level is retained.
Monthly
Check to see that the filter bed is clean of sediment and the sediment chamber is not more than 6 inches of sediment. Remove sediment as necessary.
Make sure that there is no evidence of deterioration, spalling or cracking of concrete.
Inspect grates (perimeter sand filter).
Inspect inlets, outlets and overflow spillway to ensure good condition and no evidence of erosion.
Repair or replace any damaged structural parts.
Stabilize any eroded areas.
Ensure that flow is not bypassing the facility.
Ensure that no noticeable odors are detected outside the facility.
Annually
Remove and replace the top 2-5 inches of media every 3 to 5 years for low sediment applications, more often for areas of high sediment yield or high oil and grease