The sand washing plant processes 5000 tons of raw sand per day, with a large amount of wastewater generated. The original sedimentation tank has low treatment efficiency, and the water reuse rate is less than 60%. We have customized a specialized formula for anionic polyacrylamide (PAM), which increases the coagulation and sedimentation speed by 50% and significantly improves the separation effect of sludge and water. After the supporting filter press system, the water reuse rate reaches over 95%, the moisture content of the mud cake is less than 30%, achieving zero discharge of wastewater and saving about 800000 tons of fresh water annually.