MMF stands for Multi-Media Filters are a cost-effective and efficient way to remove suspended materials from a waste stream. It is used for primary treatment in streams with low TSS levels. After an initial treatment, such as an inclined plate clarifier, they are an ideal secondary treatment option.
The purpose of a Multi-Media Filter is that it reduces the amount of suspended particles (turbidity) in incoming input water. Small particles like silt, clay, grit, organic debris, algae, and other microorganisms make up suspended solids. High-suspended-solids incoming input water can create a high-pressure drop and impair the performance of downstream filtering equipment including such reverse osmosis membranes or ion exchange beds.
In other words the process is that the MMF unit is provided to remove suspended solids which are present in the raw water. The water is to be fed from the top; water flows downward through the filter bed and exits from the bottom.
During the course of filtration, the bed is compacted raising the differential pressure across the unit and then requires backwash. The backwashing of MMF is to be done manually by the raw water. The MMF is backwashed for 10 to 15 minutes after every 23 hours.