The refined multipath quartz sand and anthracite packing filled in the filter can effectively remove the suspended solids of more than 10 um in water. When the difference of inlet pressure and water pressure reaches to a certain value, showing the filter layer has been compacted and the resistance increases. In order to prevent the filter layer from forming mud cake (causing poor filtering effect and not easy to clean), the backwashing is required for recovering. The backwashing  can be controlled in time sequences (regular clean every day), or the backwashing period can be controlled by the pressure difference before and after the equipment. It will be continued to be used after backwashing.