Coking wastewater advanced treatment and evaporative crystallization zero discharge process

Abstract

The invention provides a coking wastewater advanced treatment and evaporative crystallization zero discharge process which comprises the following steps: A) sequentially performing flocculation treatment, catalytic ozonation treatment, biological activated carbon filter treatment, multi-medium filtration, ultrafiltration treatment and first reverse osmosis concentration treatment on coking wastewater subjected to biochemical treatment, so as to obtain first treated water and first concentrated water; (B) sequentially subjecting the first concentrated water to two-stage softening treatment and second reverse osmosis concentration treatment to obtain second treated water and second concentrated water, wherein the first-stage softening adopts chemical softening and microfiltration combined filtration treatment, the second-stage softening adopts resin softening; and C) carrying out evaporative crystallization on the second concentrated water to obtain third treated water and crystal salt. The process is reasonable in linkage, stable, efficient and safe to operate and good in treatment effect, the treated water can be used as production process water or circulating cooling water replenishing water, finally zero emission of the coking wastewater is achieved, and economic benefits are remarkable.

Description

technical field [0001] The invention relates to the technical field of industrial wastewater treatment, in particular to a coking wastewater advanced treatment and evaporation crystallization zero discharge process. Background technique [0002] With the shortage of water resources in our country and the increasingly stringent discharge requirements, most enterprises in industries with large water consumption and large emissions like the coking industry will choose to carry out advanced treatment to recover part of the water for reuse as finished product water, while the rest Concentrated water will be formed after partial concentration for internal consumption of the enterprise or discharged up to standard after treatment. [0003] According to investigations, the advanced treatment of wastewater in the coking industry is generally concentrated only once, and the recovery rate is generally around 70%. The brine produced around 30% is mostly digested within the company and i...

AI Technical Summary

Problems solved by technology

Due to the complexity of organic pollutants in coking wastewater, during the membrane concentration operation, the organic matter pollutes the membrane system very seriously, which has a great impact on the stable operation of the membrane system and the service life of the membrane elements. At the same time, the subsequent evaporation and crystallization The zero discharge system will also produce a large amount of mother liquor discharge, affecting the quality of crystallized salt and other issues

In addition, coking wastewater also contains calcium, magnesium, silicon, fluorine and other ingredients that are prone to scaling. In particular, the difficult-to-clean dirt such as calcium fluoride and silicate that may be produced will have a fatal impact on the membrane system and evaporation crystallization system.

[0005] During the operation of the conventional coking wastewater advanced treatment process, due to factors such as imperfect pretreatment, process connection design or unreasonable operation, phenomena such as membrane system colloidal fouling, organic pollution and inorganic salt scaling often occur, and it is difficult to ensure that the process system Long-term stable operation

In addition, the concentrated water produced has a high content of organic matter and a large amount of water, and it is difficult to absorb it within the enterprise, which has become a restrictive factor for the development of the coking industry

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