After the wastewater is treated, it can be discharged or reused. A variety of chemicals are needed during the treatment. These agents can be divided into the following categories depending on the application:

 

(1) Flocculant: Sometimes called coagulant, it can be used as a means to strengthen solid-liquid separation. It is used in the process of primary sedimentation tank, secondary sedimentation tank, flotation cell and tertiary treatment or advanced treatment.

 

(2) Coagulant: The auxiliary flocculant acts to enhance the coagulation effect.

 

(3) Conditioning agent: also known as dehydrating agent, used for conditioning the excess sludge before dewatering, and the varieties include the above-mentioned partial flocculating agent and coagulant.

 

(4) Demulsifier: Sometimes called de-stabilizer, it is mainly used for pre-treatment of oily wastewater containing emulsified oil before air flotation. The varieties include some flocculants and coagulants mentioned above. .

 

(5) Antifoaming agent: mainly used to eliminate a large amount of foam which occurs during aeration or agitation.

 

(6) pH adjuster: used to adjust the pH of acidic wastewater and alkaline wastewater to neutral.

 

(7) Redox agent: treatment for industrial wastewater containing an oxidizing substance or a reducing substance.

 

(8) Disinfectant: used for disinfection treatment before discharge or reuse after wastewater treatment.

 

Although there are many types of the above-mentioned medicines, one type of medicine is used in different occasions, and the functions are different, and there are different names. For example, Cl2 is called a coagulant when it is used to enhance the coagulation treatment effect of sewage. It is called oxidant when it is used to oxidize cyanide or organic matter in wastewater. It is called disinfectant for disinfection treatment.