Ceramic sand filters are doped with rare earth element and processed by mix, shaping and sintering. Compared with traditional sands and coal filter material, ceramic sand filters have great advantages as follows:
   Shaped in sphere, the ceramic filter sand has a high void space, normally, its filtering velocity is 15~20 m3/h, less loss water-head, and suitable to reduce the height of filter bed and cut down the electric power and constructional expenses;
   Uniform and regular in particle size, make it easy to be cleaned, the back-flush strength is 12~20 l/m2.s; It can save the back-flush water more than 30~50%.
   High surface area, large pore volume, the ceramic sand filters is of great amount of pollutant entrapment, up to 9-10 Kg/m3, about 1.2 or 1.5 times that quartz sand filter of 7.8~9 Kg/m3;
   Great mechanical strength, less abrasion loss, and never be damaged, the ceramic sand filters can serve for a long life more than 15 years, is the 5 times or longer than that of quartz sand filters;
   Corrosion resistant, no run-off and no harmful substance dissolved out, the ceramic sand filters can ensure the treated water in consistent quality without any secondary pollution may caused by the filter as quartz sand or coal filters itself.