Commonly used agents in sludge treatment process mainly include cationic polyacrylamide (CPAM), anionic polyacrylamide (APAM), nonionic polyacrylamide (NPAM), inorganic coagulants (such as aluminum sulfate, polymerized aluminum chloride (PAC)), organic polymer flocculants (such as polydimethyldiallylammonium chloride (PDADMAC)) and so on. The following is an introduction to the characteristics and application scenarios of these commonly used agents:
1. Cationic polyacrylamide (CPAM)
Characteristics
Good flocculation effect: with cationic groups, it can neutralize the negative charge of sludge particles and form large flocs.
Wide applicability: applicable to various types of sludge.
High molecular weight: CPAM with high molecular weight has good flocculation effect and floc strength.
Application Scenario
Municipal sludge treatment: for dewatering and thickening of sludge.
Industrial sludge treatment: for sludge treatment in chemical, pharmaceutical, food and other industries.
Paper sludge treatment: improve the dewatering performance of sludge and reduce the water content of sludge.
2. anionic polyacrylamide (APAM)
Characteristics
Good flocculation: with anionic groups, suitable for neutral or alkaline sludge.
Enhance settlement: Form large flocs through bridging effect, promote sludge settlement.
Application Scenarios
Industrial wastewater treatment: particularly suitable for wastewater treatment in mining, metallurgy and coal mining industries.
Municipal sludge treatment: used in some specific sludge treatment.
3. Nonionic polyacrylamide (NPAM)
Characteristics
Weak charge characteristics: suitable for sludge with low turbidity and high organic load.
Good compatibility: good compatibility with other agents, suitable for complex water quality.
Application Scenarios
Municipal sludge treatment: used under some specific conditions.
Industrial wastewater treatment: treating wastewater from petroleum, chemical, metallurgy and other industries.
4. Inorganic coagulant
Aluminum sulfate
Characteristics
Strong electric neutralization ability: effectively neutralize the electric charge of sludge particles.
Lower cost: relatively low price, good economy.
Application Scenario
Drinking water treatment: purify drinking water.
Industrial sludge treatment: used for some specific industrial sludge treatment.
Polymeric Aluminum Chloride (PAC)
Characteristics
Good flocculation effect, applicable to various water quality.
Widely used: effective for different kinds of suspended particles.
Application Scenario
Municipal sewage treatment: for flocculation and sedimentation of sludge.
Industrial wastewater treatment: treatment of wastewater from chemical, printing and dyeing, food and other industries.
5. Organic polymer flocculant
Polydimethyl diallylammonium chloride (PDADMAC)
Characteristics
High charge density: high cationic charge density, good flocculation effect.
Fast reaction: fast reaction speed, rapid floc formation.
Application Scenario
Drinking water treatment: Removal of organic matter and suspended particles.
Paper industry: improve the filtration performance of pulp.
Petroleum industry: for drilling fluid treatment.
6. Organic coagulants
Polyethyleneimine (PEI)
Characteristics
With high-density cationic groups, strong electric neutralization ability.
Acid and alkali resistance: stable under strong acid and alkali conditions.
Application Scenario
Industrial wastewater treatment: especially suitable for heavy metal-containing wastewater and high concentration organic wastewater treatment.
Paper industry: used as pulp reinforcing agent and paper dry and wet strength agent.
Comparison and Summary
CPAM: It is suitable for all kinds of sludge treatment, especially for municipal and industrial sludge, with remarkable flocculation effect.
APAM: mainly used in industrial wastewater treatment, suitable for neutral or alkaline sludge.
NPAM: suitable for complex water quality and low turbidity sludge, good compatibility.
Aluminum sulfate: good economy, mainly used for drinking water and some industrial sludge treatment.
PAC: Widely used in municipal and industrial wastewater treatment, good flocculation effect.
PDADMAC: good and fast flocculation effect, suitable for drinking water, paper making and petroleum industry.
PEI: Specialized in heavy metal and high concentration organic wastewater treatment, strong acid and alkali resistance.
All kinds of chemicals have their own advantages, should be based on the specific sludge nature and treatment needs to choose the right chemicals, in order to achieve good treatment results and economic benefits.