The effluent from sand washing plants contains a high proportion of silt. If discharged directly, the significant sand content would have a severe impact on rivers. Consequently, this would cause considerable damage to the ecological environment. However, the use of sand is unavoidable in our daily lives; it is indispensable for the construction of buildings. Therefore, in order to protect our country’s ecological environment, discharge must meet regulatory standards before it can be released, thereby helping to create a better environment. The purification of wastewater from sand washing plants is also of paramount importance. Flocculants are used for the treatment of wastewater from sand washing plants. A commonly used flocculant for fine sand is anionic polyacrylamide (PAM), which is a highly efficient inorganic polymer. This chemical contains molecules with a high molecular weight that aggregate into large flocs. It rapidly adsorbs suspended particles in the wastewater. The particles form larger flocs through electrostatic bridging, ultimately leading to sedimentation and achieving water purification. If polyaluminium chloride and polyacrylamide are used in combination, the process becomes more effective and yields better dewatering properties.
Chemicals used:
Polyacrylamide, polyaluminium chloride
Water treatment process: First, a sample of the wastewater from the sand washing plant is taken. A beaker test is conducted in a professional laboratory to determine the correct dosage of the water treatment chemicals. Next, prepare a solution with a concentration of 0.2%–0.3%. Ordinary tap water may be used for this purpose. The solution is then added to the wastewater. Continuous and uniform stirring is essential to ensure complete dissolution. This process must continue for no less than one hour. The reaction tank must be monitored continuously, and the dosage adjusted as necessary to ensure optimal water purification results.
