Chemical coagulants include aluminium sulphate (alum), ferric chloride, lime and polymers (see Table 6.8).
Low-molecular-weight cationic polymers and inorganic aluminium and iron salt (e.g., alum and ferric sulphate) are the most commonly used positively charged coagulants [10,12,14].
What chemicals are used in coagulation?
The main chemicals used for coagulation are aluminium sulphate (alum), polyaluminium chloride (also known as PAC or liquid alum), alum potash, and iron salts (ferric sulphate or ferric chloride).
What are the common coagulants?
The commonly used metal coagulants fall into two general categories: those based on aluminum and those based on iron. The aluminum coagulants include aluminum sulfate, aluminum chloride and sodium aluminate. The iron coagulants include ferric sulfate, ferrous sulfate, ferric chloride and ferric chloride sulfate.
What does a coagulant do?
Flocculation and coagulation treatment chemicals are used in effluent water treatment processes for solids removal, water clarification, lime softening, sludge thickening, and solids dewatering. Coagulants neutralize the negative electrical charge on particles, which destabilizes the forces keeping colloids apart.
What does coagulation remove?
Coagulation-flocculation is a chemical water treatment technique typically applied prior to sedimentation and filtration (e.g. rapid sand filtration) to enhance the ability of a treatment process to remove particles. Dissolved and suspended particles are present in most of natural waters.
What two chemicals are commonly used as water coagulants?
Chemical Coagulants Used In Water Treatment
- Aluminum Sulfate (Alum) – One of the most commonly used water treatment chemicals in the world.
- Aluminum Chloride – A second choice to Alum as it is more expensive, hazardous and corrosive.
- Polyaluminum Chloride (PAC) & Aluminum Chlorohydrate (ACH)
What is flocculant for?
Flocculants, or flocculating agents (also known as flocking agents), are chemicals that promote flocculation by causing colloids and other suspended particles in liquids to aggregate, forming a floc. Flocculants are used in water treatment processes to improve the sedimentation or filterability of small particles.