abstract

Sludge dewatering agent plays a key role in the sewage treatment process, mainly promoting the dewatering of sludge, improving dewatering efficiency, reducing sludge volume, and thereby reducing treatment and transportation costs. This article introduces the mechanism and main types of sludge dewatering agents, aiming to provide reference for sewage treatment projects.

1. Introduction

Sludge treatment is an important part of sewage treatment plants, and the sludge dewatering process directly affects the final disposal and treatment cost of sludge. Dehydrating agents, as a key chemical or physical agent, make it easier to separate water from sludge through their chemical or physical effects, thereby improving dewatering efficiency. Choosing the appropriate dehydrating agent can not only significantly improve the efficiency of sludge treatment, but also reduce overall operating costs.

2. Mechanism of action of sludge dewatering agent

The mechanism of action of sludge dewatering agent mainly includes the following aspects:

Flocculation effect: Dehydrating agents use charge neutralization and bridging to aggregate small sludge particles into larger flocs, enhancing the settling and filtration performance of sludge.

Emulsification effect: Dehydrating agents can destroy emulsified oil droplets in sludge and release the water encapsulated by emulsified oil.

Cell rupture: Some dehydrators destroy microbial cell walls through chemical or physical actions, releasing bound water inside the cells and reducing the moisture content of sludge.

3. Types of sludge dewatering agents

Common sludge dewatering agents include inorganic dewatering agents, organic polymer dewatering agents, and composite dewatering agents.

Inorganic dewatering agents, such as iron salts, aluminum salts, etc., react with colloidal particles in sludge to form precipitates, achieving dewatering effects. Inorganic dehydrating agents are inexpensive, but require a large amount of usage.

Organic polymer dehydrating agents, such as polyacrylamide (PAM) and Poly(Dimethyl diallyl ammonium Chloride)  (PDMDAAC), have strong flocculation and adsorption abilities, with small usage and significant effects.

Composite dehydrating agent: By combining the advantages of inorganic and organic dehydrating agents, the dehydration effect can be improved and the dosage of the agent can be reduced through compounding.