Why is high salt wastewater difficult to treat? What are the handling methods?

Author：

Huanke

The reason why high salt wastewater is difficult to treat is partly due to the lack of corresponding technical means, and partly due to insufficient economic feasibility and reliability. At present, most treatment methods for high salinity wastewater lack effective reduction of pollutants, which can lead to waste of freshwater resources. For example, if the dilution outflow method is used, not only will it not truly reduce the emission of pollutants, but it will also waste a large amount of freshwater resources.
However, if we can separate the saltwater from the salt and concentrate the salt treatment, we can achieve the effect of zero discharge of wastewater. This can not only avoid soil and water pollution, but also improve the operational efficiency of enterprises. Therefore, the "zero discharge" technology of wastewater has become an important measure for industrial enterprises to achieve sustainable development of water resources.

High salt wastewater refers to water with high salt content, mainly sourced from three fields: seawater desalination, industrial production processes, and the recycling of industrial wastewater. These wastewater contain a large amount of inorganic salt ions and organic substances, such as potassium ions, sodium ions, chloride ions, sulfate ions, glycerol, and low-carbon chain compounds.
There are currently dozens of methods for treating high salt wastewater, including thermal method, membrane method, ion exchange method, hydrate method, solvent extraction method, and freezing method. Among them, thermal and membrane desalination technologies are currently the main technological means for large-scale industrial application. However, these methods each have their own advantages and disadvantages, and need to be selected and optimized according to different actual situations.
Membrane technology is a commonly used method for treating high salt wastewater, which can achieve desalination and concentration treatment of high salt wastewater. Membrane technology has certain requirements for the water quality of the incoming water, therefore pre-treatment (such as agent softening, filtration, ion exchange, etc.) is required to effectively reduce membrane fouling and improve the effluent quality.
Overall, the treatment of high salinity wastewater is a challenging task that requires a combination of various technical and economic measures for comprehensive treatment. In future development, we also need to further explore more efficient, environmentally friendly, and sustainable methods for treating high salt wastewater.