Walnut shell filter using high-quality pecan shells as raw material, it is processed through crushing, polishing, steam cleaning, drug anti-corrosion treatment, twice screening. This filter is very tough, and it has the advantage of abrasion resistance, compressive strength (anti-pressure 23.4kgf), chemical stability, absorption and strong Sewage Interception (absorption rate of 27-50%), anti-oil-filled. It is also easy to backwash and then regeneration, backwashing intensity is low (6.7L/Sm2), its filtration rate is fast (24-26m / h), it does not harden, not rot, will never change, you just add 5-10% per year. Oil removal rate reached 95%,oil content can go down to 5mg / g below. It can apply to oil fields, fuel-efficient environmental protection equipment and so on.