1. Reducing agent: sodium metabisulfite, sodium sulfide, sodium bisulfite

2. Alkali: lime, sodium hydroxide (caustic soda)

3. Flocculant: polyacrylamide

4. Coagulant: polyaluminum chloride, aluminum sulfate, ferric chloride

5. Oxidants: hydrogen peroxide, sodium hypochlorite

6. Acid: sulfuric acid, hydrochloric acid, oxalic acid

7. Functional agents: ammonia nitrogen remover, phosphorus remover, heavy metal catcher, decolorizer, defoamer

8. Other agents: scale inhibitors, demulsifiers, citric acid

hydrochloric acid

It can undergo neutralization reaction with alkaline wastewater to regulate the pH value of the solution, and the pH value of wastewater discharge is 6-9

Flake alkali

Alkalinity, can undergo neutralization reaction with acidic wastewater to regulate the pH value of the solution. The pH value of wastewater discharge is 6-9.


Flocculation precipitation is the process of flocculating particles in water. After adding coagulants to water, the colloidal and dispersed particles of suspended solids form flocs under the interaction of molecular forces, and they collide and condense with each other during the sedimentation process. Their size and mass continue to increase, and the sedimentation rate continues to increase. The removal rate of suspended solids not only depends on the sedimentation rate, but also on the sedimentation depth. Flocculation and sedimentation can occur during the sedimentation process of alum blooms formed by adding coagulants to surface water, organic suspended solids in domestic sewage, and activated sludge.

Polyaluminum chloride

Polyaluminum chloride can accelerate flocculation, causing impurities in water to form flocs and precipitate, quickly achieving a complete separation of water and impurities. Compared with traditional inorganic coagulants composed of low molecular crystalline salts, polyaluminum chloride is composed of inorganic polymer polymers with diverse forms. Its flocculation and sedimentation speed is fast, and its water purification effect is significant. It can effectively treat heavy metals such as arsenic and mercury in water. In addition, its pH range is wide, and it is not corrosive to equipment and pipelines. Therefore, it is widely used in fields such as drinking water, industrial water, and sewage treatment.

Sodium hypochlorite

Sodium hypochlorite is commonly used for sterilization and also for decolorization due to its oxidizing properties.

Sodium metabisulfite

Under acidic conditions, it has a reducing effect and is used for wastewater treatment in the electroplating industry. For example, in the treatment of hexavalent chromium wastewater, sodium metabisulfite can be added first to allow them to undergo a full reduction reaction. Then, other products can be added to adjust the alkali, and sodium sulfide can be added to remove heavy metals that have not completed sedimentation. This is the important role of sodium metabisulfite in the treatment of industrial wastewater.

Common Chemicals For Wastewater Treatment

Phosphorus removal agent

Phosphorus removal agents mainly use flocculation precipitation to remove phosphorus. After adding phosphorus removal agents to the wastewater, the agent quickly neutralizes the negative charges on the surface of colloidal particles in the water, which are easily combined with phosphorus ions in the water to produce precipitates. Subsequently, through sedimentation tanks or filtration processes, it can ensure that the phosphorus in the wastewater meets the discharge standards. Commonly used for phosphorus removal in domestic sewage treatment plants, pharmaceuticals, papermaking, pesticide, fertilizer plants, and other wastewater treatment.

Ammonia nitrogen remover

Ammonia nitrogen remover is mainly used to remove ammonia nitrogen from wastewater. In addition, the ammonia nitrogen in the wastewater generates insoluble nitrogen, carbon dioxide, and water, and has auxiliary removal of COD and decolorization effects. It has a fast reaction, no residue, no pollution, and a high removal rate. Suitable for the treatment of pharmaceutical factories, circuit board factories, coking plants, and domestic sewage.

Heavy metal catcher

It is a chemical agent that strongly chelates with heavy metal ions. By adopting a grafting synthesis process, the chelating groups on its branch chains can chelate heavy metals to form stable insoluble substances and precipitate. The reaction can not only occur at room temperature and a wide range of pH conditions, but also is not affected by the concentration of heavy metal ions. Even if the treated wastewater contains complex components, it can effectively precipitate various heavy metal ions in the wastewater, ensuring that the wastewater meets discharge standards.

Scale inhibitor

Also known as anti-scaling agents, they refer to a type of chemical that can inhibit the formation of scale salts such as calcium and magnesium in water. There are natural scale inhibitors such as tannins, lignin derivatives, etc; Inorganic scale inhibitors such as sodium hexametaphosphate and sodium tripolyphosphate; Organic and polymer scale inhibitors, among which polymer scale inhibitors have the best effect and have a promising future.

Sodium metabisulfite, sodium bisulfite, sodium hydroxide and polyaluminum chloride are the most common chemicals for wastewater treatment, and play important role in water treatment fileld.

Common Chemicals For Wastewater Treatment (2)