Polyacrylamide for Papermaking Wastewater Treatment: Flocculation Efficiency Test

Polyacrylamide for Papermaking Wastewater Treatment: Flocculation Efficiency Test

Papermaking wastewater is characterized by high concentrations of suspended solids, fibers, fillers, organic matter, and chemical additives. Effective treatment is essential to meet environmental discharge standards and improve water reuse efficiency. Among various treatment chemicals, Polyacrylamide (PAM) has become one of the most widely used flocculants in papermaking wastewater treatment due to its excellent solid-liquid separation performance.

Why Use Polyacrylamide in Papermaking Wastewater?

During the paper manufacturing process, large quantities of fine fibers, clay, calcium carbonate, and other suspended particles enter the wastewater stream. These particles are often too small to settle naturally.

Polyacrylamide works by:

• Neutralizing particle charges
• Bridging suspended particles together
• Forming larger and denser flocs
• Accelerating sedimentation and filtration

As a result, wastewater clarity is significantly improved, while sludge dewatering efficiency is enhanced.

Flocculation Efficiency Test

A laboratory jar test was conducted on papermaking wastewater to evaluate the performance of an anionic polyacrylamide.

Test Conditions

• Wastewater Source: Paper mill wastewater
• Initial Turbidity: 1850 NTU
• pH Value: 7.2
• PAM Type: Anionic Polyacrylamide
• Molecular Weight: High molecular weight grade

Test Procedure

1. Prepare PAM solution at the recommended concentration.
2. Add different PAM dosages to separate wastewater samples.
3. Rapidly mix for 1 minute, followed by slow mixing for 5 minutes.
4. Allow settling for 10 minutes.
5. Measure residual turbidity and observe floc formation.

Test Results

The flocculation test demonstrated a clear improvement in wastewater treatment performance as the PAM dosage increased.

• At a dosage of 2 mg/L, small flocs formed and settled slowly, achieving approximately 68% turbidity removal.
• At 4 mg/L, medium-sized flocs were observed with a moderate settling rate, resulting in about 82% turbidity removal.
• At 6 mg/L, large flocs formed rapidly and settled quickly, increasing turbidity removal to approximately 92%.
• At 8 mg/L, very large and dense flocs developed with very fast settling characteristics, achieving up to 95% turbidity removal.

The results showed that increasing PAM dosage significantly improved floc formation and settling performance. At an optimal dosage of 6–8 mg/L, large compact flocs formed rapidly, resulting in excellent clarification efficiency and substantial reduction of suspended solids.

Benefits of Using Polyacrylamide

• High flocculation efficiency
• Reduced sludge volume
• Faster sedimentation rate
• Lower operating costs
• Improved wastewater recycling capability
• Enhanced performance of clarifiers and dewatering equipment

Conclusion

Polyacrylamide is a highly effective solution for papermaking wastewater treatment. Through proper dosage optimization, paper mills can achieve excellent turbidity removal, reduce treatment costs, and improve environmental compliance. Laboratory flocculation tests remain the most reliable method for determining the optimal product type and dosage for specific wastewater conditions.

For best performance, selecting the appropriate ionic type and molecular weight of polyacrylamide based on wastewater characteristics is recommended.

Contact Information

📱 WhatsApp: +86 132 7158 1132
📧 Email: cathy@cnycchem.com