4.4 What are the O&M Requirements?

Sand filters need to be monitored constantly to ensure high performance. This involves checking the quality of the influent and effluent, as well as the head loss of the filters. Over time, the effectiveness of sand filters reduces due to the accumulation of solids and microbial growth. Therefore, frequent cleaning or replacement of filter material is necessary.

Monitoring of hydraulic loading rate and TSS

High hydraulic loading rate and TSS concentration can reduce the treatment performance of the filter and clog the filter media.


Inspection of filter media

The filter should be inspected regularly for damage, wear, leakage, and cleanliness of its media.


Monitor the filter run length

The filter run length is the time between two cleaning of the filter, and it depends on the size of the sand and the organic loading rate on the filter surface.


Cleaning and replacing the filter media

Raking improves the treatment efficiency by cleaning the top layer of sand (2-5 cm) when it is plugged. The frequency depends on the hydraulic loading rate and the TSS concentration in the influent and can range from 1 to 12 months. Manual or mechanical cleaning can be done.


For further information, please click on the Materials tab at the top of the page.

Further Reading:

  • Intermittent Biological Sand Filters for Wastewater Treatment: Overview on process, design and O&M for ISF. (Link)