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Flocculation is a process by which a chemical coagulant added to the water acts to facilitate bonding between particles, creating larger aggregates which are easier to separate. The method is widely used in water treatment plants and can also be applied to sample processing for monitoring applications.
What is the basic principle of flocculation?
Flocculation refers to the process used to bring the coagulated particles together so that they can combine to form larger, settleable, and filterable masses of particles called floc. Zeta potential is defined and its role in coagulation described.
What is the result of flocculation?
Flocculation allows for the destabilized particles to agglomerate into larger particles that can be removed by gravity through sedimentation. The mixing energy must be low enough to allow mixing and particle contact while not providing so much energy that the delicate floc particles shear apart.
Is flocculation and coagulation the same?
Coagulation is a chemical process and flocculation is a physical process, In coagulation, the process involves the utilization of a coagulant that has the ability to destabilize the charged particles which are not settleable whilst flocculation involves a similar destabilization process that is achieved through Dec 10, 2017.
What is meant by coagulation and flocculation?
Coagulation-flocculation: The use of chemical reagents to destabilise and increase the size of the particles; mixing; increasing of flog size, A physical separation of the solids from the liquid phase. This separation is usually achieved by sedimentation (decantation), flotation or filtration.
What is flocculant for?
Flocculant refers to the chemical or substance added to a suspension to accelerate the rate of flocculation or to strengthen the flocs formed during flocculation.
What is an example of flocculation?
Flocculation and coagulation treatment chemicals are used in effluent wastewater water treatment processes for solids removal, water clarification, lime softening, sludge thickening, and solids dewatering. Examples of ChemTreat coagulation products include aluminum salts, iron salts, and polyelectrolytes.
What makes a good flocculant?
Polymers are useful as flocculants because they are robust molecules and sometimes carry charges. Because they are so large, small particles can get trapped in the curves of the polymer causing them to accumulate a mass heavy enough to prevent their retention in solution.
How is flocculation prevented?
Design contact times for flocculation range from 15 or 20 minutes to an hour or more, and flocculation requires careful attention to the mixing velocity and amount of mix energy. To prevent floc from tearing apart or shearing, the mixing velocity and energy are usually tapered off as the size of floc increases.
What causes flocculation to occur?
In dispersed clay slurries, flocculation occurs after mechanical agitation ceases and the dispersed clay platelets spontaneously form flocs because of attractions between negative face charges and positive edge charges.
Is alum a coagulant or flocculant?
To accomplish this, the water is treated with aluminum sulfate, commonly called alum, which serves as a flocculant. Raw water often holds tiny suspended particles that are very difficult for a filter to catch. Alum causes them to clump together so that they can settle out of the water or be easily trapped by a filter.
What is coagulant mean?
A coagulant is a compound or agent which is added to a vessel to help thicken something. Adding a coagulant such as aluminum sulfate to water permits particles to come together and results in the formation of a flocculent mass. A coagulant is a compound or agent which is added to a vessel to help thicken something.
Why is alum added to the water?
In a typical water treatment process: Alum is used to coagulate suspended particles, algae, protozoa, viruses, bacteria, and some metal ions (such as iron and manganese) into larger particles. Chlorine is added to kill bacteria that may have entered the water during the filtration process.
What is an example of coagulation?
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.
Where is flocculation used?
Flocculation is a process by which a chemical coagulant added to the water acts to facilitate bonding between particles, creating larger aggregates which are easier to separate. The method is widely used in water treatment plants and can also be applied to sample processing for monitoring applications.
What happens during coagulation?
Blood clots and coagulation Blood vessels shrink so that less blood will leak out. Tiny cells in the blood called platelets stick together around the wound to patch the leak. Blood proteins and platelets come together and form what is known as a fibrin clot. The clot acts like a mesh to stop the bleeding.
How long should flocculant sit?
Flocculant, although fast-acting, will still need around 8-16 hours to work its magic. It’s easiest to do this overnight.
How often can you use flocculant?
You can reuse a clarifier after 5-7 days, but if you’re constantly seeing cloudy water, there may be other problems. Adding too much flocculant can cause its own issues.
Can you add too much flocculant?
Too much floc can detract from the beauty of your pool. Flocculants are substances that help clear the cloudiness and restore the clarity to your swimming pool water. You can use too much floc, however.
Which coagulant is used for sewage treatment?
Ferric chloride is widely used for sewage treatment and Alum is widely used for water treatment.
What is flocculation simple?
Flocculation, in physical chemistry, separation of solid particles from a liquid to form loose aggregations or soft flakes. These flocculates are easily disrupted, being held together only by a force analogous to the surface tension of a liquid.
What chemical is used for flocculation?
Coagulants such as alum (Al2(SO4)3-14H2O), iron salts (ferric chloride (FeCl36H2O), ferric sulfate (Fe2(SO4)3) and ferrous sulfate (FeSO47H2O)), lime (Ca(OH)2) and organic polyelectrolytes are used as flocculation aids during wastewater treatment.
How do you dissolve flocculant?
Bleach or sodium hypochlorite can be used to break down polyacrylamide-based flocculants. As bleach is a powerful oxidizer, it will cause the scission of certain polymer chains with a loss of consistency and consequently its viscous nature.
What is a natural flocculant?
BEWAT natural products are a very specific range focused on treating wastewater. They are mainly composed of polymers of natural origin extracted from plants, algae or animals. Among these are polysaccharides and water soluble substances that act as coagulation and / or flocculation agents.
Can you drink flocculant?
In addition, coagulants and flocculants are expensive, which is why you want to avoid adding more than are necessary to the water; drinking water treatment plants use “jar tests” to identify the optimal coagulant and flocculant concentrations. Do not drink any of your water samples—even if they appear clear.
