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How to Filter Brackish Water?

May. 24, 2021


The desalination process of brackish water mainly includes reverse osmosis desalination, distillation desalination and electrodialysis desalination process. It is mainly a process of desalinating brackish water. The reverse osmosis desalination process has the characteristics of low energy consumption, small footprint, and reliable operation effect. Therefore, the desalination of brackish water generally uses reverse osmosis desalination process.

1. Disinfection, Coagulation and Sedimentation

Since the brackish water contains bacteria, viruses, etc., sodium hypochlorite should be added for disinfection before adding medicine and coagulation, and then coagulant and flocculant are added in the mixer to flocculate and settle the suspended substances and colloids in the brackish water to reduce the turbidity of the brackish water.

2. Coarse Filtration

The coarse filtration is mainly composed of a multi-media filter and activated carbon filter. The multi-media filter mainly removes large particles, colloids, suspended matter, iron, manganese in brackish water. Activated carbon filter is mainly responsible for adsorbing peculiar smell, organic matter, colloid and residual chlorine in brackish water. The main purpose of the coarse filtration system is to reduce the turbidity and chromaticity of the brackish water and reduce the pollution to the next level of filtration system

3. Microfiltration

The microfiltration system is mainly composed of security filters and filtering consumables. Because the salt content in brackish water is very high, security filters generally use FRP Filter Housings with good corrosion resistance. FRP Cartridge Filter Housings or FRP Bag Filter Housings can be selected according to the requirements.


Filtration consumables can be determined according to the available land area and required water flow on site. If the available land area is small and water flow requirement is large, you can choose High Flow Filters. If there is no requirement for land area and water flow, you can also choose to use Melt Blown Cartridges, String Wound Cartridges or Liquid Filter Bags.


4. Reverse Osmosis Filtration

The reverse osmosis filtration system is the most important part of the whole brackish water desalination process. The salt removal treatment of brackish water is mainly completed by reverse osmosis filtration system, which can intercept the dissolved salt, heavy metal ions, bacteria, viruses in the brackish water, so as to achieve the effect of desalinizing the brackish water into fresh water.

In the desalination process of brackish water, if the hardness of the raw water is very high, you can choose to install a water softener before the microfiltration system to reduce the hardness of the water. This can prevent the reverse osmosis system from forming dirt due to the high concentration of calcium and magnesium ions, reducing the filtration efficiency of the reverse osmosis system and shortening the service life.

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