pac
PAC & ACH
PAC (Polyaluminum Chloride) and ACH coagulants for water treatment — effective in removing turbidity, color, and suspended solids from drinking water and wastewater.
PT Beta Pramesti Asia
1. PAC (Polyaluminum Chloride)
Full name: Polyaluminum Chloride
General chemical formula: Alₙ(OH)ₘCl₍₃ₙ₋ₘ₎
Function and use:
PAC is a coagulant used to purify water by binding fine colloidal particles to form flocs that are easily deposited.
PAC is used in:
- Drinking water treatment
- Industrial wastewater treatment
- Paper industry (for fiber separation)
- Textile industry (process water purification)
Advantages of PAC:
- Effective over a wider pH range (pH 5-9)
- Lower usage dose compared to alum
- Produces less sludge
- Does not lower the pH of the water too much
Disadvantages:
- Relatively higher price than alum
- Can leave aluminum residue if the dose is excessive
2. ACH (Aluminum Chlorohydrate)
Full name: Aluminum Chlorohydrate
General chemical formula: Al₂(OH)₅Cl
Function and use:
ACH is also an aluminum-based coagulant, with a higher active aluminum content than PAC.
ACH is widely used for:
- Premium drinking water treatment (e.g. bottled water)
- Industrial applications with high hygiene standards (food, pharmaceutical)
- Cosmetics (especially antiperspirants/deodorants)
Advantages of ACH:
- Has high basicity (70-83%), meaning it is more stable and efficient
- Produces faster and larger flocs
- Reduces dissolved organic content (DOC/TOC) better
- More dose-efficient than PAC
Disadvantages:
- More expensive than PAC
- Sensitive to pH extremes (less effective at pH < 5)
Brief Comparison of PAC vs ACH
| Aspect | PAC | ACH |
|---|---|---|
| General form | Liquid or solid | Liquid |
| Basicity (OH- content) | 50-70% | 70-83% |
| Coagulation efficiency | Good | Very good |
| Required dosage | Medium | Low |
| Stability | Good | Very good |
| General application | Drinking water, waste water | Premium drinking water, cosmetics |
Conclusion
-
PAC is suitable for general use in water treatment plants as it is economical and effective.
-
ACH is used for premium grade applications or high hygienic standards, where clarity and aluminum residues are strictly controlled.
Use the ACH water treatment selection, starting-dose, and jar-test guide before a full-scale plant trial.