Polyacrylamide in Wastewater Treatment: Mechanism, Application, and Industry Cases

2025-10-03

Polyacrylamide (PAM) is a widely used flocculant in municipal sewage and industrial wastewater treatment. Its mechanism includes:

√ Charge Neutralization – Cationic polyacrylamide neutralizes negative particles.

√ Bridging Adsorption – Polymer chains form networks that enhance flocculation.

√ Flocculation-Sedimentation – Promotes large floc formation for clear water.

Application Method of Polyacrylamide

√ Dissolve PAM into 0.1%–0.5% solution with stirring.

√ Add PAC first, then polyacrylamide for better results.

√ Dosage usually 1–10 ppm, optimized by jar tests.

√ Inject at well-mixed points in tanks or pipelines.

Precautions for Polyacrylamide Usage

1. Avoid solution temperature above 60℃.

2. Use fresh solution within 24 hours.

3. Choose anionic PAM for high turbidity, cationic PAM for organic-rich wastewater.

4. Store in a dry, cool environment.

Industry Application

Papermaking Wastewater Treatment

Anionic polyacrylamide recovers fibers, accelerates sedimentation, and reduces COD/BOD in papermaking wastewater.

Textile Dyeing Wastewater Treatment

Cationic polyacrylamide binds with dye molecules, enhancing decolorization and flocculation. Works effectively with PAC.

Coal Washing Wastewater Treatment

Anionic polyacrylamide quickly forms large flocs, improves sludge separation, and lowers equipment wear.

FAQ

Q1: What is the mechanism of polyacrylamide in wastewater treatment?
A1: It works via charge neutralization and bridging adsorption, promoting flocculation and sedimentation.

Q2: How should polyacrylamide be applied?
A2: Dissolve into 0.1%–0.5% solution, determine dosage via jar test, and often combine with PAC.

Q3: What precautions should be taken when using polyacrylamide?
A3: Avoid high temperature, prepare fresh solutions, and select the right type for wastewater.

Q4: What is the typical dosage of polyacrylamide?
A4: Usually 1–10 ppm, depending on water quality.

Q5: How effective is polyacrylamide in different industries?
A5: It recovers fibers in papermaking, improves decolorization in textile wastewater, and enhances sludge separation in coal washing.