Difference between PAM and PAC in terms of implementation

The key differences between PAM (Polyacrylamide) and PAC (Polyaluminum Chloride) in terms of implementation lie in their chemical properties, applications, and how they are used in water treatment processes. Here’s a breakdown:

Role in Water Treatment

• PAC:
  • Coagulant: PAC is primarily used to destabilize suspended particles in water by neutralizing their charges.
  • It promotes the formation of flocs (large clumps of particles), which settle more easily during sedimentation or filtration.
  • Often used in the first stage of water treatment.

 

• PAM:
  • Flocculant: PAM is mainly used to bind the smaller particles into larger, more stable flocs, improving sedimentation and dewatering efficiency.
  • It works after coagulation (typically following PAC or another coagulant).

 

Method of Use

• PAC Implementation:
  • Added into raw water in the initial stages to coagulate particles.
  • Requires proper mixing to ensure even distribution.
  • Works effectively across a wide pH range, but the optimal dose depends on the water’s turbidity and alkalinity.
• PAM Implementation:
  • Typically applied after the coagulation process to improve floc strength and sedimentation.
  • Requires precise dilution (often in low concentrations) and gentle mixing to avoid damaging flocs.
  • Comes in different types (anionic, cationic, nonionic, and zwitterionic) tailored to specific water and application needs.

 

Dosage

• PAC:
  • Dosage is generally higher because it acts on the raw water to coagulate particles.
  • Typical range: 1-20 mg/L, depending on the water quality.
• PAM:
  • Dosage is lower as it primarily strengthens and settles the flocs.
  • Typical range: 0.1-1 mg/L, as even small amounts are highly effective.

 

Equipment and Preparation

• PAC:
  • Simple equipment needed for dosing, but it’s sensitive to water quality changes.
  • Easy to handle in both solid and liquid forms.
• PAM:
  • Requires specialized preparation and dosing equipment to mix the product properly without causing polymer degradation.
  • Mixing tanks and precise dilution systems are crucial for effectiveness.

 

Application Scenarios

• PAC:
  • Used in drinking water treatment, industrial wastewater treatment, and municipal sewage systems.
  • Effective in high-turbidity water.
• PAM:
  • Often used in sludge dewatering, paper-making, and industrial processes where fine particle removal or water recovery is critical.
  • Suitable for low-turbidity and high-concentration sludge applications.  

 

Cost Implications

• PAC:
  • Generally more economical for large-scale coagulation processes.
• PAM:
  • Higher cost per unit but used in smaller quantities, making it cost-efficient for specific applications.

 

Summary

• PAC is the first step in particle removal, neutralizing charges and forming flocs.
• PAM is used to enhance the settling and dewatering process after coagulation.
• Their combined use provides optimal water treatment efficiency, reducing overall costs and improving water clarity.

 

FAQs

1. Is PAC a coagulant or a flocculant?

PAC (Poly Aluminium Chloride) is primarily a coagulant. It helps in aggregating small particles into larger clumps, making them easier to remove during sedimentation. It is widely used in water treatment to enhance clarification and filtration.

2. What is the difference between PAC and alum?

Both PAC and alum (Aluminium Sulfate) are coagulants used in water treatment. However, PAC is more efficient, requires lower dosages, and works across a broader pH range than alum. PAC also produces less sludge, reducing the overall waste disposal cost.

3. Is PAC soluble in water?

Yes, PAC is highly soluble in water. This allows it to disperse quickly, ensuring rapid action on contaminants for effective water treatment.

4. What are PAC and PAM used for in water treatment?

PAC and PAM serve distinct but complementary roles:

• PAC (Poly Aluminium Chloride) – A coagulant that neutralizes charges on suspended particles, allowing them to clump together.
• PAM (Polyacrylamide) – A flocculant that binds coagulated particles into larger aggregates, making them easier to settle and filter out.

5. How does PAC contribute to sustainable water treatment practices?

PAC enhances sustainability by:

• Reducing chemical consumption due to its high efficiency.
• Minimizing sludge production, lowering disposal costs.
• Working effectively at lower temperatures and across a wide pH range, reducing energy consumption.

6. Can PAC be used with other treatment chemicals?

Yes, PAC can be combined with other treatment chemicals like:

• PAM (Polyacrylamide) for improved flocculation.
• Boiler water treatment chemicals to prevent scaling and corrosion.
• Deflocculating agents to fine-tune coagulation and filtration performance.

By leveraging advanced water treatment solutions like PAC and PAM, industries and municipalities can achieve cost-effective, efficient, and environmentally friendly water purification processes.