Polyacrylamide, usually called PAM, is a flocculant used in wastewater treatment, sludge dewatering, mining wastewater, paper mill wastewater and textile wastewater. The main selection question is whether anionic, cationic or nonionic PAM is suitable for the process.
PAM type comparison
| PAM type | Typical use | Selection note |
|---|---|---|
| Anionic PAM | Inorganic suspended solids, mining wastewater, clarification | Often tested where solids carry positive or neutral characteristics |
| Cationic PAM | Municipal sludge, organic sludge dewatering | Common starting point for sludge dewatering trials |
| Nonionic PAM | Special acidic or mixed wastewater conditions | Use when jar test shows better floc formation |
What to test
- Ionic type and charge density.
- Molecular weight range.
- Dissolution time and stock solution quality.
- Floc size and floc strength.
- Filtrate clarity.
- Final sludge moisture.
- Dosage per ton of dry solids.
Common mistakes
- Choosing PAM only by price per ton.
- Using undissolved polymer solution with fisheyes.
- Testing only one charge density.
- Ignoring equipment type such as belt press, screw press or centrifuge.
- Not checking pH and sludge source changes.
FAQ
Is cationic PAM always best for sludge dewatering?
It is often a good starting point for organic sludge, but the best product must be confirmed by testing the actual sludge.
Why does PAM sometimes fail?
Common causes include wrong ionic type, poor dissolution, overdosing, underdosing, pH change, or a mismatch with the dewatering equipment.
For type selection support, visit HydroChemix PAM or request a PAM recommendation.