... surface, microporous interior, large specific surface area, and high porosity, etc. Under the same conditions, ceramic filter grains enjoy faster filtration speed ... in slow filtration pool, fast filtration pool, monolayer filtration pool or multi-layer filtration pool, or be used to treat city water, industrial water and ... Φ4-6, Φ16, Φ25, Φ32 Ceramic filter grain and sands for waste water treatment