How to treat wastewater containing high salt
How to treat industrial high-salt wastewater? High-saline wastewater refers to wastewater containing organic matter and at least 3.5% (mass concentration) of total dissolved solids (TDS). This kind of waste water comes from a wide range of sources. One is the chemical, pharmaceutical, petroleum, paper making, dairy processing, food canning and other industrial production processes, which will discharge a large amount of waste water. The water contains not only many organic pollutants with high concentration, but also a large amount of calcium, sodium, chlorine and sulfate plasma. So how to treat this kind of wastewater?
How to treat industrial high-salt wastewater
1. Double-membrane pretreatment process
First, use a semi-permeable membrane with a pore size of 20-2000Ao (10-6.5-10-4.5cm) for ultrafiltration, which can intercept proteins, various enzymes, bacteria and other colloidal substances and macromolecular substances in the concentrated solution, while water, solvents, small molecules and salt forming ions can pass through the membrane and enter the permeable water.
As the water content of the permeate decreases, but the salt content does not change, the salt concentration of the permeate increases. At this time, a semi-permeable membrane with a pore size of 1-20Ao (10-7.5-10-6.5cm) is used for reverse osmosis. Inorganic salts, sugars, amino acids, BOD, COD, etc. are trapped in the concentrated solution. Only water and solvent enter the permeate water. The concentration of salt in the concentrated solution is further increased and sent to evaporation crystallization for desalination.
The advantage of double-film desalination is that the water volume of evaporative crystallization desalination is greatly reduced, thus significantly reducing the operating cost and investment of evaporative crystallization desalination.