Nut shell filter can remove the oil and solidity completely, and it is easy to be rewashed. it is widely used in purifying waste water which contains oil, industrial waste water and civil water. It is a kind of new filter product which can replace quartz sand, and can improve water quality, but decreases water treatment cost. Analyze items unit Testing index Analyze items unit Testing index specific gravity g/cm3 ~1.23 water % ＞1 oil % 0.25 oil removal % 98 unit weight of heap g/cm3 ~0.60 Wear rate % ＜1.5 porosity % 48 granule diameter mm granule diameter mm 0.5-0.8 24-32 1.2-1.6 12-16 0.8-1.25 16-24 1.6-2 10-12 Ca0 53% Na 0.02% K 0.025% Mg 0.03% Fe 0.02% Zn 50%