Flocculants are a type of substance that can reduce or eliminate the precipitation stability and polymerization stability of dispersed particles in water, causing them to agglomerate and coagulate into aggregates for removal. According to chemical composition, flocculants can be divided into three categories: inorganic flocculants, organic flocculants, and microbial flocculants.

1. The commonly used inorganic polymer flocculants include PAC (polyaluminum chloride) and PFS (polymeric iron sulfate); Easy to tolerate in water and has a certain degree of corrosiveness. It can be added in solution form or in particle form.

2. The commonly used organic polymer flocculant is PAM (polyacrylamide); It is soluble in water, but the dissolution rate is slow. Generally, it is first prepared into a solution and then added. It is divided into anionic and cationic types. Anionic type is generally used as a sewage flocculant, while cationic type is generally used for sludge dewatering. PAM is prone to water absorption, deliquescence, and clumping, and its storage location must be dry.

3. Microbial flocculant is a new type of water treatment agent that utilizes biotechnology to extract and purify microorganisms or their secretions, resulting in safety, efficiency, and natural degradation. Microbial flocculants can overcome the inherent shortcomings of inorganic and synthetic organic polymer flocculants, achieving pollution-free emissions.