Method for reutilization of water resources and transformation and utilization of salt in waste water

Abstract

The invention discloses a method for reutilization of water resources and transformation and utilization of salt in waste water. The method includes the following steps that the pH value of the waste water is adjusted to be alkaline for hardness removal, generated settling sludge is separated out of the water and then dried to serve as a boiler desulfurizing agent, and the obtained waste water is subjected to ultra-filtration and multiple levels of reverse osmosis concentration; the waste water obtained in the former step is subjected to nano-filtration, and univalence salt and high-valence salt are separated; the univalence salt is further separated and transformed, prepared purified sodium chloride strong brine is concentrated, and the sodium chloride strong brine serves as a chloro-alkali raw material; potassium chloride is added into mixed brine which is separated out through nano-filtration and contains high-valence ions and univalence ions for a replacement reaction to generate potassium sulphate and sodium chloride, potassium sulphate and sodium chloride are separated through freezing crystallization and high-temperature evaporative crystallization, generated potassium sulphate serves as a raw material for producing chemical fertilizer, separated sodium chloride serves as a chloro-alkali production raw material, and the water and the salt in the waste water can be completely recycled.

Description

technical field [0001] The invention relates to the field of waste water resource recycling, in particular to a method for water resource reuse and salt conversion and utilization in waste water. Background technique [0002] At present, many domestic enterprises mainly use reclaimed water to reuse or evaporate and crystallize miscellaneous salts to treat wastewater. Treatment, water "zero discharge" at the same time solid waste causes secondary soil pollution or water pollution. [0003] Although there are methods in the prior art involving the recycling of waste water, they generally deal with a specific problem in the waste water, and none of them involve recycling all the water in the waste water and the salt at different prices, and need to add flocculants, etc. . For example, CN201210501778.1 discloses a method for resource utilization of acidic wastewater, including the following steps: a, adjusting the pH value of the acidic wastewater to 4.5-7; b, adding a floccul...

AI Technical Summary

Problems solved by technology

[0002] At present, many domestic enterprises mainly use reclaimed water to reuse or evaporate and crystallize miscellaneous salts to treat wastewater. Treatment, water "zero discharge" at the same time solid waste causes secondary soil pollution or water pollution

[0003] Although there are methods in the prior art involving the recycling of waste water, they generally deal with a specific problem in the waste water, and none of them involve recycling all the water in the waste water and the salt at different prices, and need to add flocculants, etc.

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