Salt-containing wastewater salt recycling system and method, salt-containing wastewater treatment system and method

Abstract

The invention provides a salt-containing wastewater salt recycling system which is used for recycling salt in salt-containing wastewater containing sodium chloride, sodium sulfate and sodium nitrate acquired after salt-containing wastewater is desalted. The salt recycling system comprises a first nano-filtration unit, an ozone oxidation unit, a chelating resin adsorption unit, a sodium sulfate freezing crystallization unit, a sodium chloride evaporative crystallization unit, a sodium nitrate freezing crystallization unit and a second nano-filtration unit. The invention further provides a salt-containing wastewater salt recycling method. The invention further provides a salt-containing wastewater treatment system and method. According to the system and method, high-purity products such as sodium chloride, sodium nitrate and mirabilite can be effectively recycled from the salt-containing wastewater, unserviceable mixed salt is omitted, resourceful treatment of the salt-containing wastewater is achieved, zero discharge of the salt-containing wastewater is really achieved, scaling and blocking of devices such as nano-filtration units can be effectively relieved, so that long-time, stable and reliable operation of the salt recycling system and a wastewater treatment system can be ensured.

Description

technical field [0001] The invention relates to the field of waste water treatment, in particular to a salt recovery system and a salt recovery method for salt-containing waste water, and a treatment system and processing method for salt-containing waste water. 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 is also gradually increasing. The petrochemical, coal chemical, fine chemical, power plant and other industries generally carry out advanced treatment and reuse of the effluent from the sewage treatment plant or the sewage from the circulating water. During the recycling process, the pollutants such as salt and refractory organic matter in the water are continuously concentrated. It is enriched to form high-salt wastewater containing organic matter. The treatment requirements for these high-salt and organic-containing wastewater are increas...

AI Technical Summary

Problems solved by technology

Taking the zero discharge of coal chemical wastewater as an example, in the currently operating mixed salt evaporation and crystallization device, the discharge of mother liquor can reach 15-18% of the water volume of evaporated raw materials. These mother liquors have no way out, except for some projects that are spray-dried into waste salt. Most are intractable and become a headache

At the same time, due to the unreasonable treatment process, in the process of concentration and evaporative crystallization of salty wastewater, organic matter and scaling ions will cause foaming, boiling point increase, scaling and equipment failure during the process of concentration of wastewater and evaporative crystallization. Corrosion, which makes it difficult for the concentration and evaporation crystallization process to run stably for a long period of time, which increases the cost of operation, equipment cleaning and maintenance

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