The main agents used to reduce the moisture content of sludge include polyacrylamide (PAM), ‌ polyaluminum chloride (PAC), ‌ polyferric sulfate (PFs), ‌ bioenzyme preparations and organic high polymer (sludge synergist). ‌

Polyacrylamide (PAM) : ‌ is a water-soluble polymer, ‌ has excellent flocculation and condensation properties. ‌ it reacts with suspended particles in sewage through hydrogen bonding, ‌ makes them aggregate to form a large flocculent, ‌ so that it is easy to settle and separate. The advantages of ‌PAM include efficient, ‌ fast, ‌ safe, ‌ non-toxic, and ‌ relatively high price. ‌

Polyaluminum chloride (PAC) : ‌ is an inorganic polymer, ‌ has a wide range of coagulant effects. ‌PAC collects suspended particles in sewage through adsorption and condensation, ‌ forms a large flocculent, ‌ is easy to settle and separate. ‌PAC is cheaper, ‌ but requires a larger dosage. ‌

Polyferric sulfate (PFs) : ‌ is an efficient and low-cost sludge dehydrating agent. ‌ aggregates suspended particles in sewage through adsorption and condensation, ‌ forms a large flocculent, ‌ is easy to settle and separate. ‌PFs is used in relatively small amounts ‌ but may cause corrosion to equipment. ‌

Biological enzyme preparation: ‌ is a new type of sludge dehydrating agent. ‌ decomposes organic matter in sludge by enzyme and ‌ makes it drier. ‌ bioenzyme preparations have the advantages of high efficiency, ‌ environmental protection, ‌ safety, etc. ‌, but the price is relatively high. ‌

Organic high polymer (sludge synergist) : ‌ collects suspended particles in sewage through adsorption and condensation, ‌ forms a large flocculent, ‌ is easy to settle and separate. ‌ organic polymer has the advantages of high efficiency, ‌ speed, ‌ safety, etc. ‌, but the price is relatively high. ‌

These agents help to reduce the moisture content of the sludge through different mechanisms of action ‌, thereby improving the dewatering efficiency and treatment effect of the sludge.