The Role of Coagulants in Water Treatment
Coagulation is the first and most critical step in water treatment. The right coagulant choice determines the efficiency of the entire treatment process including sedimentation, filtration, and disinfection.
PAC (Polyaluminium Chloride)
Best for: Municipal drinking water, general wastewater. PAC is a pre-hydrolyzed aluminum coagulant that forms flocs rapidly across a wide pH range. It is the most widely used coagulant in modern water treatment plants globally.
PAM (Polyacrylamide)
Best for: Sludge dewatering, mining, papermaking. PAM is a high molecular weight polymer flocculant available in three charge types:
- Anionic PAM — For mineral-rich, alkaline wastewater
- cationic PAM — For organic-rich sludge dewatering
- Nonionic PAM — For acidic or specialty applications
PFS (Polyferric Sulfate)
Best for: Color removal, heavy metal precipitation, high-pH water. PFS is an iron-based coagulant that excels at removing dissolved organic matter and heavy metals. It produces denser flocs than aluminum-based coagulants.
Quick Selection Guide
| Application | Recommended | Reason |
|---|---|---|
| Drinking water | PAC (drinking grade) | Low residual Al, fast settling |
| Textile wastewater | PAC + PAM | Color removal + flocculation |
| Sludge dewatering | Cationic PAM | High cake solids |
| heavy metal removal | PFS | Excellent metal precipitation |
| Mining tailings | Anionic PAM | High settling rate |
Unsure which product fits your application? Contact HydroChemix for free technical consultation.