Abstract: In order to optimize the treatment process of "three wastes" in concrete mixing station and improve the environment of the plant, the solid-liquid separation process of wastewater was studied for the problems of wastewater and waste residue produced in the production and operation of mixing station. By optimizing and improving the traditional wastewater treatment process, the fine sand recovery process is applied to the wastewater treatment system of the mixing station. The +75 μm fine sand is efficiently recovered by centrifugal separation principle to form three products of aggregate, sand and mud, which can effectively separate and recover the wastewater and waste residue of the mixing station. The wastewater is reused for production. The recovery rate of +75 μm fine sand is increased from 68.86% to more than 99.00%, and the zero discharge of wastewater is successfully realized. The resource recovery rate is 100%.

Key words: mixing station, cyclone, fine sand recovery, comprehensive utilization