While the construction of hydropower stations, it will produce a lot of sand and gravel wastewater. The main disposal methods of water recovery include: natural sedimentation and mechanical dewatering. Generally speaking, natural precipitation is to removal big solid particles whose size is over 0.1mm, but mechanical method is mainly for fine sands.
Firstly, the sand slurry passes through the fine sand recovery machine (cyclone & vibrating screen). Then，will add the inorganic flocculant polyaluminum chloride (PAC) and organic flocculant polyacrylamide (PAM) in a certain proportion. Then the coagulant aggregates and precipitates the colloidal particles in the tailing slurry. In the clarifier, the supernatant flows into the clean water tank for reuse. At the bottom, a high-concentration mud is formed. After that the thicker sludge enters the chamber filter press for sludge dewatering. Under the high pressure of the filter press pump, solid-liquid separation is carried out, and finally filter cakes are formed and realize the dry stack.
The method is easy to operate. It not only can effectively remove the suspended solids in the machine-made sand wastewater, but also has a better dehydration effect and higher cost performance. On the one hand, stone powder and water all are recovered; on the other hand, the natural environment is protected.