In the water treatment process of multi-media filter, filtration generally refers to the process of quartz sand and anthracite filter material layer intercepting suspended impurities in water and making water clear. Quartz sand is the most common porous material for filtration. With granular filter materials, powders and various fibers. Commonly used with quartz sand, anthracite activated carbon, magnetite, garnet, porous ceramics and plastic balls and so on.
filter The multi-media filter media in the filter tank are high-quality homogeneous gravel, quartz sand, magnetite, anthracite and other filter media. These filter media are scientifically and orderly distributed in the filter tank according to their specific gravity and particle size. For example, anthracite with small specific gravity and slightly larger particle size is placed in the top layer of the filter bed, quartz sand with moderate specific gravity and small particle size is placed in the middle layer of the filter bed, and gravel with large specific gravity and particle size is placed in the bottom layer of the filter bed The bottom. This ratio ensures that the filter will not produce disordered layer when backwashing, so as to ensure the interception capacity of filter material.
Multi media filter (also known as mechanical filter) is a typical multi-media filter with layered anthracite, sand, fine garnet or other materials as the bed.
The top layer of the bed consists of the lightest and coarsest grade materials, while the heaviest and finest grade materials are placed in the lower part of the bed. The principle is deep filtration - the larger particles in the water are removed at the top layer, and the smaller particles are removed at the deeper part of the filter medium. So that the water quality can reach the standard after coarse filtration.
The principle of the equipment is that when the raw water passes through the filter material from top to bottom, the suspended solids in the water will be intercepted by the surface of the filter layer due to adsorption and mechanical resistance; When the water flows into the middle of the filter layer, because the sand particles in the filter layer are arranged more closely, the particles in the water have more chances to collide with the sand particles, so the flocs, suspended solids and sand particles in the water adhere to each other, and the impurities in the water are trapped in the filter layer, so as to obtain the clarified water quality. The suspended solids in the filtered effluent can be less than 5 mg / L.
The multi-media filter is a process of adding several filter media to make the water with high turbidity pass through the filter under a certain pressure to effectively remove the suspended solids and impurities and make the water clear. The commonly used filter media are quartz sand, anthracite, manganese sand, etc., which are mainly used for the pretreatment of water quality deep purification. Different filter media can be added according to the process requirements.