Learn the basics of Coagulation Chemistry. This video is an excerpt from the American Water College Water Treatment Exam Review course.
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After a quick overview we look at the different types of coagulants.
There are three kinds of coagulants. Namely: Trivalent, Bivalent and Monovalent.
Trivalent Coagulants include:
Bivalent Coagulants include:
Monovalent Coagulants include:
We also take a look at different uses for different compounds.
Aluminum Sulfate – The most common and is often used with cationic polymer.
Aluminum Chlorohydrate – Produces less sludge and is less corrosive than aluminum sulfate.
Ferric chloride – Effective over a wider pH range than alum.
Ferric sulfate – Often used as part of he lime softening process.
Ferrous Sulfate – Less pH dependent than alum.
Aluminum Polymer – Polyaluminum Chloride (PAC) and Poly Aluminum Sulfate are examples.
Cationic Polymers – Large molecules, synthetic polyelectrolytes.
Sodium Aluminate – Often used with alum because it improves the alum process.
Sodium Silicate – Used to make the coagulant aid activated silica. Activated silica is added in addition to a primary coagulant to enhance the coagulation process.