Reclaimed Water-High Salt Wastewater Treatment, Salt Purification/Salt Resource Utilization

1. The generation and harm of high salt wastewater

High salt wastewater refers to wastewater with a total salt content of at least 1% by mass. It mainly comes from chemical plants and the collection and processing of oil and natural gas. This type of wastewater contains various substances, including salt, oil, organic heavy metals, and radioactive substances. The generation pathways of saline wastewater are extensive, and the amount of water is increasing year by year. A large amount of high salt wastewater, if discharged directly or diluted, causes water resource waste on the one hand; On the other hand, it will have a bad impact on the environment, accelerate the eutrophication of Rivers and Lakes, cause the collapse of the soil ecosystem, produce stench, affect the water quality, change the color and visibility of the water body, and form a large number of suspended solids in the water body.

2. General treatment methods for high salt wastewater

Wastewater is first removed from large suspended particles before entering the regulating tank, and then separated by electrodialysis. Concentrated water enters the MVR for evaporation, while fresh water enters the anaerobic and aerobic biological treatment systems. Finally, after sedimentation in the settling tank, it is discharged from the discharge tank.

However, under this process, the phase of MVR evaporated crystalline salt is poor, and in most cases, it must be treated as hazardous waste, with higher outsourcing costs. The problems of blockage and high energy consumption in the evaporation system also arise.

3. Jiangsu Haipu's waste salt regeneration process

Due to the high cost and energy consumption of treating high salt wastewater, resource utilization of high salt wastewater can not only reduce treatment costs, but also facilitate the recovery and utilization of salt in high salt wastewater.

At present, Jiangsu Haifan conducts special adsorption pretreatment on high salt wastewater to remove organic matter, divalent cations, and color pollutants from the original wastewater before entering the electrodialysis system.

In this way, the concentration of salt in the middle compartment of the two membranes will decrease due to the directional migration of ions, while the two compartments near the electrode are respectively the concentration chambers for anions and cations, and finally achieve desalination in the desalination chamber in the middle.

This process has been successfully applied to dozens of enterprises, with obvious advantages such as no need to add other materials for separation, high yield, low cost, and good quality.