Coagulants & Flocculants
Used to aggregate suspended solids and improve sedimentation:
- Aluminum sulfate (Alum)
- Ferric chloride (FeCl₃)
- Polyaluminum chloride (PAC)
- Polyacrylamide (PAM) – available in cationic, anionic, and nonionic grades
pH Adjusters
For neutralization and process stability:
- Sulfuric acid (H₂SO₄) – pH reduction
- Hydrochloric acid (HCl) – aggressive acid for rapid adjustment
- Sodium hydroxide (NaOH) – pH elevation and alkalinity control
- Calcium hydroxide (Ca(OH)₂) – lime for softening and pH buffering
Oxidizing Agents
Break down organic contaminants and support disinfection:
- Hydrogen peroxide (H₂O₂) – oxidative treatment
- Sodium hypochlorite (NaOCl) – chlorination and microbial control
- Potassium permanganate (KMnO₄) – oxidation of iron, manganese, and organics
Sludge Conditioners
Improve dewatering and reduce sludge volume:
- Ferric sulfate (Fe₂(SO₄)₃) – enhances floc strength
- Lime (CaO or Ca(OH)₂) – stabilizes and conditions sludge
- Cationic polymers – improve cake formation and water release
Scale Inhibitors
Prevent mineral buildup in pipes and equipment:
- Sodium hexametaphosphate (SHMP)
- Phosphonates (e.g., HEDP, ATMP) – effective in hard water systems
Biocides & Algaecides
Control microbial growth and biofilm formation:
- Isothiazolinone – broad-spectrum biocide
- Glutaraldehyde – effective against bacteria and fungi
- Copper sulfate (CuSO₄) – algae control in open systems
Dechlorination Agents
Neutralize residual chlorine before discharge or reuse:
- Sodium bisulfite (NaHSO₃)
- Sodium thiosulfate (Na₂S₂O₃)
