Polyacrylamide (PAM) Field Problems & Solutions

Polyacrylamide (PAM) is widely used in wastewater treatment, sludge dewatering, sand washing, mining, and industrial processes. However, many plants face on-site problems even when PAM is applied.

These problems are usually not caused by PAM itself, but by wrong selection, wrong dosage, or poor system matching.

This article explains the most common PAM field problems, their real causes, and practical solutions used in real plants.

1. Poor Flocculation Effect

Common Symptoms

• Flocs are very small
• Water remains turbid
• Sedimentation is slow
• PAM dosage keeps increasing but no improvement

Main Causes

❌ Wrong PAM Type

Using cationic PAM for anionic wastewater, or wrong molecular weight.

👉 PAM selection must match:

• pH value
• Type of suspended solids
• Organic content

❌ Incorrect Dosage

• Too little → no bridging
• Too much → flocs break and re-disperse

❌ Poor Mixing Conditions

• PAM not fully dispersed
• Short reaction time
• Excessive shear force

Solutions

• Conduct jar tests before full-scale use
• Optimize molecular weight and charge density
• Adjust mixing speed and reaction time

2. Sludge Dewatering Is Not Effective

Common Problems

• Sludge cake too wet
• Mud sticks to filter cloth
• Low filtration speed

Main Causes

❌ Unstable Inlet Pressure

Fluctuating sludge pump pressure reduces floc stability.

❌ Dirty Filter Cloth

Blocked cloth prevents water release.

❌ High Clay or Fine Particles

Clay increases viscosity and traps water.

Solutions

• Stabilize inlet and pump pressure
• Clean or replace filter cloth regularly
• Use PAC + PAM combination to break clay structure

3. Muddy Water and Tank Overflow

Common Situations

• Sedimentation tank overflows
• Effluent water is muddy
• Sludge floats instead of settling

Causes

• Inlet flow too high
• Sedimentation time too short
• Overdosing PAM

Solutions

• Match inlet flow with tank capacity
• Reduce dosage and extend reaction time
• Improve baffle and flow design

4. “Water Poisoning” Phenomenon

What Is Water Poisoning?

• PAM suddenly stops working
• No flocs form
• Circulation system collapses

Common in:

• Sand washing plants
• Mining wastewater
• Variable raw materials

Root Causes

• Raw water quality changes suddenly
• Wrong chemical combination
• Excessive chemical accumulation

Solutions

• Neutralize charge using cationic PAM
• Add polyaluminum chloride (PAC) to reset coagulation
• Stabilize raw water if possible

Conclusion

Most PAM field problems are system problems, not product problems. Correct selection, dosage, mixing, and system design can greatly improve:

• Flocculation efficiency
• Sludge dewatering
• Water clarity
• Operating cost