Among all types of filters, sand and gravel filters are the most effective in dealing with organic and inorganic impurities in water. These filters have a strong ability to filter out and retain impurities and do not require continuous water supply. When the organic matter content in water exceeds 10mg/L, regardless of the inorganic matter content, a sand and gravel filter should be selected. Filter tanks are usually made in a cylindrical shape, with a diameter of 0.6 to 1.2 meters and the thickness of the filter material inside the tank being approximately 25 to 50 centimeters. It allows for the accumulation of several centimeters of impurities on the surface of the filter material, which is far superior to mesh and disc filters.

The sand and gravel filter system usually operates in combination with multiple tanks, so that the filtered water in one group of tanks can be used to backwash the impurities in other tanks. The greater the flow rate, the more tanks need to operate in parallel. The fully automatic sand and gravel filter has a long service life. When the system is in the filtration state, it is early in the advanced treatment of sewage. It can remove suspended solids from the raw water to determine the type and dosage of coagulant. During the initial operation of the filter, the filtration effect is good.

Filtration of industrial water - with systematic requirements for water quality. For example, the filtration of oxygen gun water in steel mills, water supply for boilers and heat exchangers, etc., can filter out impurities in the water and prevent blockages in pipelines and nozzles. Filtration system for industrial circulating water. The treatment of raw water - It can filter surface river water, lake water, sea water, reservoir water, well water and urban tap water as water sources for urban small-scale quality water supply, etc., to remove sand particles, suspended solids, algae, organic matter and other substances in the water.