What are coagulant aids?
A coagulant aid is a chemical or material, which is not a coagulant, used to assist or modify coagulation. Coagulant aids add density to slow-settling flocs and add toughness to the flocs so that they do not break up during the mixing and settling processes.
What is the function of coagulant?
3 Coagulants. Coagulants and flocculation processes are used to remove colloidal impurities: suspended particles such as bacteria, clay, silts, and organic matter from the contaminated water. This produces large flock aggregates that can be removed from the water in subsequent clarification/filtration processes.
What is sedimentation with coagulation?
Large, heavy particles settle out readily, but smaller and lighter particles settle very slowly or in some cases do not settle at all. Because of this, the sedimentation step is usually preceded by a chemical process known as coagulation. Coagulation is usually accomplished in two stages: rapid mixing and slow mixing.
What is flocculation and coagulation?
Coagulation is the destabilization of colloidal particles brought about by the addition of a chemical reagent called as coagulant. Flocculation is the agglomeration of destabilized particles into microfloc and after into bulky floccules which can be settled called floc.
Why are coagulant aids used?
Coagulant aids are used to improve the settling characteristics of floc produced by aluminium or iron coagulants. The most commonly used coagulant aids are synthetic polyelectrolytes, although some soluble starch products are still in use.
What is coagulant example?
Examples of primary coagulants are metallic salts, such as aluminum sulfate (referred to as alum), ferric sulfate, and ferric chloride. Cationic polymers may also be used as primary coagulants. 2. Chemicals commonly used for primary coagulants include aluminum or iron salts and organic polymers.
Which is example of coagulant?
Examples of primary coagulants are metallic salts, such as aluminum sulfate (referred to as alum), ferric sulfate, and ferric chloride. Cationic polymers may also be used as primary coagulants.
What is coagulant made of?
The two most commonly used salt coagulants are 1) calcium sulfate (gypsum) and 2) magnesium chloride combined with calcium chloride (nigari salts). Calcium sulfate is the most traditional and widely used coagulant for tofu.
What is difference between sedimentation and sedimentation with coagulation?
sedimentation is the separation of a suspension of solid particles into a concentrated slurry and a supernatant liquid, either to concentrate the solid or to clarify the liquid while coagulation is the precipitation of suspended particles as they increase in size (by any of several physical or chemical.
What are coagulants?
Coagulants are a substance which cause particles in a liquid to curdle and clot together. Coagulation treatment chemicals are used in effluent water treatment processes for solids removal, water clarification, lime softening, sludge thickening, and solids dewatering.
What is coagulation with example?
Coagulation is the breakdown of a colloid by changing the pH or charges in the solution. Making yogurt is an example of coagulation wherein particles in the milk colloid fall out of solution as the result of a change in pH, clumping into a large coagulate.
Which is the most commonly used coagulant?
Iron and aluminium salts are the most widely used coagulants but salts of other metals such as titanium and zirconium have been found to be highly effective as well.