System and method for electrodialysis concentration of high-salt industrial wastewater without adding of chemicals for softening pretreatment

Abstract

The invention discloses a system and method for electrodialysis concentration of high-salt industrial wastewater without adding of chemicals for softening pretreatment, and the system comprises a wastewater tank, a simple medium filtration pretreatment mechanism, an electrodialysis concentration separation mechanism, a desalting liquid pool, a concentrate liquid pool, a concentrated liquid membrane filtration treatment mechanism, a sludge dewatering mechanism, and a crystallization salt making mechanism, wherein the concentrated liquid membrane filtration treatment mechanism is provided with asubmerged membrane filtration device, a produced water first outlet of the submerged membrane filtration device is in connection with the electrodialysis concentration separation mechanism to form acirculation, a produced water second outlet is connected to the crystal salt making mechanism, and an outlet of concentrated water trapped by the submerged membrane filtration device is connected to the sludge dewatering mechanism. The whole process shortens the process, and does not need to add the chemicals for softening and removing hardness ions such as calcium and magnesium before the high-salt industrial wastewater enters the electrodialysis concentration separation mechanism, reduces the production amount and the discharge amount of inorganic precipitated sludge, and reduces investmentand operating cost of the whole system.

Description

technical field [0001] The invention relates to the technical field of environmental protection water treatment, in particular to an electrodialysis concentration system and method for high-salt industrial wastewater that does not require softening and pretreatment with chemical addition. Background technique [0002] As the national environmental protection policy becomes more and more stringent, various industrial enterprises such as the power industry, coal chemical industry, papermaking and printing and dyeing industries are faced with the requirement of waste water reduction and reuse, or even zero liquid discharge. The main components of the discharged waste water of various industrial enterprises It is soluble inorganic salts and organic matter, among which organic matter can be removed by biochemical treatment or advanced oxidation treatment, but soluble inorganic salt can only be removed by continuous concentration until it precipitates and crystallizes into solid sa...

AI Technical Summary

Problems solved by technology

In the process of continuous concentration of inorganic salts, some inorganic salts with low solubility will be precipitated first, such as calcium salts, magnesium salts, etc. Concentration continues, and the membrane module will be damaged. Therefore, the process of removing hardness by chemical softening reaction must be used for pretreatment. This requires adding lime, NaOH and sodium carbonate into the water, which will not only increase the operating cost, but also generate a lot of water. Softened sludge needs to be treated separately, and generally acid is added to adjust the pH after adding chemicals to soften, which introduces additional soluble inorganic salts to the water, increasing the overall investment in the reuse of high-salt industrial wastewater and zero discharge cost and running costs

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