The multi-layer filtration of the backwash filter adopts a filter material of different materials to form a double-layer or a three-layer filter layer, the filter medium with a lower density is in the upper layer, and the filter material with a higher density is in the lower layer. The double-layer filter material generally adopts anthracite and quartz sand, and the three-layer filter material generally adopts anthracite, quartz sand and magnetite or garnet.
When the backwash filter is backwashed, it is automatically stratified because of the different density of the filter material. This filtering method has the advantages of large intercepting capacity, short filtering period, good effluent quality, and high filtration speed. Backwash filters can be used for water treatment in a variety of circulating water systems, in addition to hydraulic circulation clarifiers and mechanical agitation clarifiers.
In the hydraulic circulation clarifier, the circulation of the sludge is based on the principle of the ejector, that is, the power of the inflow water is used to promote the backflow of the sludge, so the clarifier is characterized by no rotating parts and a simple structure. The mechanically stirred clarifier is characterized by the use of mechanically agitated slag backflow and contact reactions.http://www.inocofiltration.com/