What are the difficulties in treating high-salt wastewater? How to treat high-salt wastewater? This is a problem that needs to be solved in the chemical industry, especially in the fine chemical industry. Kang Jinghui Xiaobian talks with you about the difficulties in treating high-salt wastewater.
　　First, the necessity of high-salt wastewater treatment
　　Before understanding the difficulties in treating high-salinity wastewater, let's look at why we should treat high-salinity wastewater.
　　Industrial salty wastewater and industrial waste gas (including dust) discharged during the production and operation of fine chemicals will pollute the environment around the factory to a certain extent and destroy the living environment of residents living around the factory, so it is particularly important to control the industrial park.
　　In the recycling of waste in chemical production areas, especially for fine industries, the total amount of waste salt discharged by more and more enterprises is increasing every year, and its treatment and reuse has become a bottleneck restricting the current production development of enterprises.
　　If the toxic and harmful substances in the waste can be effectively separated, the inorganic salts in the waste can be well recycled, which can not only protect the environment, but also get good economic benefits for enterprises.
　　For any fine chemical enterprise, in order to achieve sustainable development, it is necessary to combine environmental development with economic development. Only when the wastewater, waste salt and other wastes in the production area are purified by appropriate processes can China's economic greening level be improved.
　　Second, the difficulties in the treatment of high-salt wastewater
　　At present, it is difficult to treat industrial waste salt and wastewater, mainly because the output benefit is not proportional to the input cost, and the repeated effect in technical practice is not ideal.
　　For any enterprise, it needs a model that can be copied quickly if it wants to be transformed and operated on a large scale quickly. However, from the analysis of fine chemical production, the composition and content of drainage water will be different in different periods by using the same process, which leads to different treatment results of the same purification process, so it is technically difficult.
　　Secondly, most fine enterprises pay great attention to interests, and many fine production enterprises choose to dilute the salty wastewater and then transfer it to the sewage treatment plant for unified centralized takeover, and do not tend to invest higher costs for remediation.
　　For the treatment of fine production plants, toxic and harmful raw materials must be replaced from the source to achieve green and clean production. However, the most important problem is the discharge of salty wastewater. Because of the high salinity in the water, biological bacteria die and the biochemical system cannot maintain normal operation. In order to make the sewage treatment plants operate normally, it is generally required that the salt concentration of wastewater should not exceed 5%. At present, the sewage treatment plants refuse high-salinity wastewater, which leads to a large amount of waste salt accumulation in the factory or warehouse of enterprises.
　　These are the difficulties in the treatment of high-salt wastewater. At present, the common zero-discharge technology of chemical wastewater is to comprehensively apply chemical, biochemical and physical processes such as pretreatment, membrane separation, evaporative crystallization and drying, to concentrate solid salts and impurities in wastewater, and the obtained condensed water will continue to be reused. The remaining wet solid-phase by-products containing water will be properly treated, and after reaching the sampling conditions of membrane equipment, membrane separation, concentration and purification will be carried out, and the obtained concentrated solution will enter an evaporative concentration device, and inorganic salts in wastewater will be precipitated into finished products.