Table of Contents
The coagulation process involves adding iron or aluminum salts, such as aluminum sulphate, ferric sulphate, ferric chloride or polymers, to the water. These chemicals are called coagulants, and have a positive charge.
What is the process of coagulation in water?
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.
What causes coagulation of water?
Chemicals (coagulants) are added to the water to bring the nonsettling particles together into larger, heavier masses of solids called floc. 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.
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.
Which is best coagulant?
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 the difference between flocculant and coagulant?
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 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 is water treated?
The treatment process for drinking water varies according to the type and quality of the raw water. Common treatment methods include aeration, flocculation, sedimentation, filtration, and disinfection to ensure water is of a safe quality for consumption.
How does a coagulant work?
Coagulants work by creating a chemical reaction, eliminating negative charges that cause particles to repel each other. The action of these bubbles forces clots or flocs of particles to the water surface where they can be skimmed off. Dissolved air flotation is an alternative to sedimentation.
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.
What are natural coagulants?
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.
Why coagulant is used in water treatment?
Coagulation treatment neutralizes the negative electrical charge on particles, which destabilizes the forces keeping colloids apart. Water treatment coagulants are comprised of positively charged molecules that, when added to the water and mixed, accomplish this charge neutralization.
What is the first step of raw water treatment?
Coagulation and flocculation are often the first steps in water treatment. Chemicals with a positive charge are added to the water. The positive charge of these chemicals neutralizes the negative charge of dirt and other dissolved particles in the water.
How do you make coagulation?
To induce coagulation, a coagulant (typically a metallic salt) with the opposite charge is added to the water to overcome the repulsive charge and “destabilize” the suspension. For example, the colloidal particles are negatively charged and alum is added as a coagulant to create positively charged ions.
What makes a good coagulant?
The best coagulant is therefore a pre-hydrolysed species with a high basicity. PACl has been found to be very suitable for lime softening applications. The advantage of a low basicity coagulant is even more pronounced in full softening applications, and the non-sulphated PACl is the coagulant of choice.
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 causes coagulation?
Blood Clot Formation When you cut or injure yourself, your body stops the bleeding by forming a blood clot. Proteins and particles in your blood, called platelets, stick together to form the blood clot. The process of forming a clot is called coagulation.
Is coagulation reversible?
Coagulation is irreversible, the proteins cannot be turned back into their liquid form.
What materials Cannot be removed from wastewater?
When wastewater arrives at the treatment plant, it contains many solids that cannot be removed by the wastewater treatment process. This can include rags, paper, wood, food particles, egg shells, plastic, and even toys and money.
What are the 5 stages of water treatment?
These include: (1) Collection ; (2) Screening and Straining ; (3) Chemical Addition ; (4) Coagulation and Flocculation ; (5) Sedimentation and Clarification ; (6) Filtration ; (7) Disinfection ; (8) Storage ; (9) and finally Distribution. Let’s examine these steps in more detail.
Why alum is used as coagulant?
When alum is added to water, it reacts with the water and results in positively charged ions. Coagulation removes colloids and suspended solids from the water. These particles have a negative charge, so the positively charged coagulant chemicals neutralize them during coagulation.
What coagulation means?
Coagulation: In medicine, the clotting of blood. The process by which the blood clots to form solid masses, or clots. More than 30 types of cells and substances in blood affect clotting. The process is initiated by blood platelets. The blood cells and plasma are enmeshed in the network of fibrils to form the clot.
