If the mud content in the construction sand is too high, the strength of the concrete will be reduced during use. 

Therefore, in the sand making process, sand washing is required to remove the mud content in the sand, which requires a large amount of water and generates a large amount of sand washing sewage. If the direct discharge is not only polluting the surrounding water quality, but also increasing the cost of sand washing water. Polyacrylamide is a kind of linear polymer, which has good adsorption and flocculation effect. The polyacrylamide used for sand washing can quickly flocculate and precipitate the impurities such as soil in the sand washing sewage, and after treatment, the sand washing sewage can be clarified to meet the discharge standard or recycled, which will not only not pollute the environment but also save the water consumption in the sand washing process and thus save the sand washing cost.