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Coagulation and flocculation are used to separate the suspended solids portion from the water. Suspended particles vary in source, charge, particle size, shape, and density. Correct application of coagulation and flocculation depends upon these factors.
What is the ultimate goal of coagulation and flocculation?
Terms in this set (50) What is the purpose of coagulation and flocculation? The purpose of coagulation and flocculation is to remove particulate impurities and color from the water being treated.
What is the purpose of coagulation?
Coagulation is a process used to neutralise charges and form a gelatinous mass to trap (or bridge) particles thus forming a mass large enough to settle or be trapped in the filter.
What is the coagulation process?
Coagulation is the chemical water treatment process used to remove solids from water, by manipulating electrostatic charges of particles suspended in water. This process introduces small, highly charged molecules into water to destabilize the charges on particles, colloids, or oily materials in suspension.
Is FeCl3 a coagulant?
Ferric chloride (FeCl3) is the most common iron salt used to achieve coagulation. Its reactions in the coagulation process are similar to those of alum, but its relative solubility and pH range differ significantly from those of alum. Both alum and ferric chloride can be used to generate inorganic polymeric coagulants.
Is alum positive or negative?
For example, the colloidal particles are negatively charged and alum is added as a coagulant to create positively charged ions. Once the repulsive charges have been neutralized (since opposite charges attract), van der Waals force will cause the particles to cling together (agglomerate) and form micro floc.
What is coagulant and flocculant?
Flocculants differ from coagulants in that they are often polymers, whereas coagulants are typically salts. Generally speaking, anionic flocculants are used to catch mineral particles while cationic flocculants can capture organic particles.
What is PAC coagulant?
Polyaluminum chloride (PAC) coagulant has been developed and used in water and wastewater treatment since the 1980s throughout the world (Jiang, 2001). PAC is made by partial hydrolysis of acid aluminum chloride solution using a specific reactor.
Is coagulation good or bad?
Blood clotting is a natural process; without it, you would be at risk of bleeding to death from a simple cut. Blood clots inside the cardiovascular system are not always so welcome. A clot in the coronary arteries near the heart can cause a heart attack; one in the brain or the arteries serving it, a stroke.
Is coagulation reversible?
Coagulation is irreversible, the proteins cannot be turned back into their liquid form.
Does alum increase pH?
When the alum dose is increased, the pH decreases. Thus, the alum dose and pH are linked (Gone et al., 2008) . For alum coagulation, it is a concern because alum can be toxic to aquatic species due to decreasing pH.
How is blood coagulation tested?
Blood Tests for Clotting Disorders APTT (Partial Thromboplastin Time) This test is used as a screening test to evaluate bleeding disorders. PT (Prothrombin Time) von Willebrand Antigen Test. Ristocetin (Rist oh SEE tin) Co-Factor. Factor Assays. Platelets. Platelet Aggregation Testing. Multimers.
What can be used as a flocculant?
The following natural products are used as flocculants: Chitosan. Isinglass. Moringa oleifera seeds (Horseradish Tree) Gelatin. Strychnos potatorum seeds (Nirmali nut tree) Guar gum. Alginates (brown seaweed extracts).
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 the purpose of flocculation in water treatment?
Flocculants are substances that promote the agglomeration of fine particles present in a solution, creating a floc, which then floats to the surface (flotation) or settles to the bottom (sedimentation). This can then be more easily removed from the liquid.
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.
What two chemicals are commonly used as water coagulants?
Aluminum sulfate (alum) is the most common coagulant used for water purification. Other chemicals, such as ferric sulfate or sodium aluminate, may also be used.
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.
What are the 4 steps of coagulation?
1) Constriction of the blood vessel. 2) Formation of a temporary “platelet plug.” 3) Activation of the coagulation cascade. 4) Formation of “fibrin plug” or the final clot.
What is flocculation wastewater?
Flocculation is a water treatment process where solids form larger clusters, or flocs, to be removed from water. This process can happen spontaneously, or with the help of chemical agents. One of the requirements for treated water leaving wastewater plants is the removal of suspended solids.
What are the side effects of alum?
If experienced, these tend to have a Severe expression i fluid accumulation around the eye. throat swelling. a feeling of throat tightness. a skin ulcer. hives. a shallow ulcer on the skin. fainting. puffy face from water retention.
Is na2so4 a coagulant?
Sodium sulfate is a well-known coagulant for PVA, and it is used in the coagulation bath of PVA before wet spinning of vinylon fibers.
Why is flocculation important?
Applying flocculation ensures a high flux over filtration units as well as efficient and cost effective separation of cell material from supernatant. Used water can contain significant amounts of suspended particulate matter, which often takes long to sediment.
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.
Is gypsum a flocculant?
Gypsum can coagulate or bridge clay particles, which accelerates settling. Flocculants should be used to prevent damage to sensitive water resources such as ponds, lakes and trout streams or whenever turbidity control is required. The best thing to do is a jar or bucket test using slightly varying rates of gypsum.
