Multi-medium filter is to use one kind of or several kinds of filtration mediums to filter impurities in water of higher turbidity like suspended matter, organics and colloid by means of mechanical interception under a certain pressure to make water clear. Quartz sand, anthracite coal, manganese sand and other filtering materials of different grain sizes will be provided based on different water quality, which are mainly used for removing turbidity, pretreatment of softened water and purified water. The silt density index (SDI) can be below 3°, thus extending the service life of the post equipment.
After the multi-media filter runs for a certain period, its filter layer intercepts and absorbs a certain amount of sundries and stains, resulting in poor quality of effluent water, increasing differential pressure between water inlet and outlet pipes and reduction in flow of single filter. When a certain limit is reached, it is required to import compressed air to conduct back flushing against equipment and flush filtering materials.
