Anion exchangers, also known as sodium ion exchangers, are categorized into sodium ion exchangers, anion-cation beds, mixed beds, and more. The outer shell of ion exchange columns (devices) is generally made of materials such as rigid polyvinyl chloride (PVC), rigid polyvinyl chloride composite fiberglass (PVC-FRP), plexiglass (PMMA), plexiglass composite transparent fiberglass (PMMA-FRP), rubber-lined steel (JR), and rubber-lined stainless steel. They are mainly used in boilers, thermal power plants, chemical industry, light industry, textile, medicine, biology, electronics, atomic energy, and as pre-treatment for pure water treatment. They are also used in industrial production for hard water softening and deionized water preparation, as well as for decolorization and purification of food and drugs, recovery of precious metals and chemical raw materials, and treatment of electroplating wastewater. The ion exchanger regeneration involves four basic processes.

1. Small Backwash: The purpose is to clean suspended impurities in the ion exchange resin layer. When the anion and cation exchangers are set behind the antiscalant of the reverse osmosis, because the inlet water is very clean, it is not necessary to perform it every time. A small backwash can be performed after ten runs.

2. Draining: The backwash water enters the exchanger from the middle drain and is discharged from the upper part of the exchanger. Backwash until the effluent is clear, which usually takes 10-15 minutes. Open the valve to release the water in the pipe until there is no water in the pipe.

3. Regeneration: Sodium hydroxide enters the anion exchanger, and the regeneration liquid flows through the resin layer from bottom to top at a rate of approximately 5m/h of empty tower velocity.

4. Forward Wash: Close the drain pipe, open the inlet valve, and after water comes out of the vent valve, open the forward wash valve and close the vent valve to forward wash the resin. The flow rate is the same as during operation. Continue until the effluent water quality meets the requirements, open the outlet valve, close the lower drain valve, and put it into operation.