Treatment Methods for High Salt Wastewater

1. Overview of high salinity wastewater

High salt wastewater refers to saline wastewater with a salt content exceeding 1% of the total salt content, including high salt domestic wastewater and high salt industrial wastewater. It mainly comes from industrial production, domestic sewage, food processing plants, pharmaceutical plants, chemical plants, etc. that directly utilize seawater. In addition to organic pollutants, these wastewater also contain a large amount of inorganic salts, such as Cl^-, SO₃^2-, SO₄^2- ions. These high salt and high organic wastewater, if discharged directly without treatment, will inevitably cause great harm to aquatic organisms, drinking water, and industrial and agricultural production water.

The common characteristics of this type of concentrated wastewater are that it cannot be simply treated by biochemical methods, and the physical and chemical treatment process is complex, with high treatment costs, making it a recognized high difficulty wastewater treatment in the sewage treatment industry.

2. Haipu customized processing technology

In order to meet the discharge standards of high salt wastewater, MVR evaporation or three effect evaporator is commonly used to achieve the goal. Specifically, the salt containing wastewater enters the evaporation device and undergoes a concentrated crystallization process through evaporation and condensation, separating into desalinated water and concentrated crystal slurry waste liquid. Inorganic salts and some organic matter can be crystallized and separated as solid waste treatment, and desalinated water can be returned to the production system to replace softened water for utilization. However, in practical applications, due to the high organic content in high salt wastewater, problems such as evaporator blockage, low salt evaporation efficiency, and dark salt evaporation color often occur, which pose challenges to the stable operation of enterprises.

The high salt wastewater adsorption process developed by Jiangsu Haipu Functional Materials Co., Ltd. pretreats the wastewater before salt evaporation, removes the majority of organic matter in the wastewater by adsorption, improves the stability of subsequent evaporation system operation, and reduces the chromaticity of salt evaporation. The solid salt is transformed from hazardous waste to solid waste, reducing the operating costs of enterprise production and providing an effective solution for the treatment of high salt wastewater.

Jiangsu Haipu Functional Materials Co., Ltd. is committed to the research and industrialization of high-performance adsorbents and catalysts. In 2018, it was approved as the Suzhou Adsorption and Catalytic Functional Nanomaterials Engineering Technology Research Center. Through years of independent research and development, it has achieved international leading levels in ion exchange technology and adsorption technology, nano inorganic material hybridization technology, etc., realizing the serialization of adsorption and catalytic products and successfully applying them in the fields of environmental protection and resource recycling. With a series of independently developed high-performance adsorbents and catalysts as the core, combined with self-developed process technology, Haipu has become a professional supplier of green and environmental protection solutions.

When using Haipu's adsorption process to treat high salt wastewater, the wastewater is pre filtered to remove suspended and particulate matter, and then enters the adsorption tower for adsorption. The special adsorption material filled in the adsorption tower can adsorb the organic matter in the wastewater on the surface of the material, significantly reducing the COD of the effluent. After adsorption saturation, specific desorption agents are used to desorb the adsorbent material, allowing it to regenerate, and this process is continuously repeated. The adsorption treatment process flow of high salt wastewater is shown in the following figure.

Figure 1 High salt wastewater treatment process

3. Case introduction

This newly built high salt wastewater adsorption treatment facility has a total designed wastewater treatment capacity of 100m³/d. The wastewater is a mixed high salt wastewater in the factory, with a dark color and brown color after evaporation. The solid waste treatment cost is high. Haipu has customized the process design for the wastewater, and the wastewater design indicators are shown in the table below.

Table 1 Wastewater Design Parameters Table

Figure 2 Appearance of raw water (left) and effluent (right)

Figure 3 Salt evaporation diagram of effluent

Haipu's customized adsorption process can deeply adsorb and remove organic matter from wastewater, reduce the color of the effluent, improve the stability and quality of the subsequent salt evaporation system, reduce the production and operation costs of the enterprise, and provide guarantee for stable production on site for customers.

4. Advantages of adsorption method

• Deeply removing organic matter from wastewater, reducing COD and chromaticity of adsorbed effluent, can ensure white salt evaporation in effluent, and improve the stability of subsequent evaporation systems;

• Using specially modified adsorption materials, with large adsorption capacity, low equipment investment, and low operating costs;

• The process flow is simple and can achieve full automation operation, making operation and maintenance convenient.

• It can be arranged in multiple layers, with a small footprint and a short installation cycle.