Salt-containing wastewater treatment system and treatment method

Abstract

The invention provides a salt-containing wastewater treatment system. The salt-containing wastewater treatment system comprises a clarification and softening unit, a membrane filtration unit, a cationic resin softening unit, a carbon dioxide removal unit, a first reverse osmosis unit, a chelate resin softening unit, a second reverse osmosis unit, a nanofiltration unit, a freezing crystallization unit and other treatment units. The invention further provides a salt-containing wastewater treatment method. According to the salt-containing wastewater treatment system and treatment method, salt-containing wastewater can be converted into products such as acid, alkali, mirabilite and the like required to be purchased from the outside in the water treatment process, mixed organic matter containing salt which cannot be used is not generated, scaling and sewage blocking due to reverse osmosis and nanofiltration can be greatly relieved, long-time, stable and reliable operation of the treatment system can be guaranteed, the wastewater treatment cost is reduced, the concentrated water can be completely treated in the system, no secondary pollution is caused, and zero discharge and resource utilization of the wastewater are realized.

Description

technical field [0001] The invention relates to the field of wastewater treatment, in particular to a system and method for treating salty wastewater. Background technique [0002] With the shortage of water resources and the further improvement of environmental protection standards, the reuse rate of water in industrial projects has gradually increased. At present, advanced treatment and reuse of effluent from sewage treatment plants or circulating water drainage are generally carried out. During the reuse process Pollutants such as salinity and refractory organic matter in the water are continuously concentrated and enriched, forming high-salt and organic-containing wastewater. The treatment requirements for these high-salt and organic-containing wastewater are increasingly urgent, especially in coal chemical projects. The consumption of water resources is huge, and it is generally required to achieve zero discharge of wastewater. The current zero discharge treatment techn...

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Problems solved by technology

The evaporation process consumes a lot of energy, equipment investment and operating costs are high, and the mixed salt formed by this method is complex and contains a large amount of organic matter, which is difficult to use

In addition, during the concentration and evaporative crystallization of saline wastewater, due to the presence of Ca in the wastewater 2+ , Mg 2+ , F - , SiO 2 、HCO 3 - Due to the unreasonable concentration process, scaling and equipment corrosion will occur in the process of wastewater concentration and evaporation crystallization, making it difficult for the concentration and evaporation crystallization process to run stably for a long period, and increase the operation and equipment cleaning and maintenance costs

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