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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. Coagulation and flocculation occurs in successive steps, allowing particle collision and growth of floc.
What role does coagulation play in water treatment?
It is, however, an important primary step in the water treatment process, because coagulation removes many of the particles, such as dissolved organic carbon, that make water difficult to disinfect. Because coagulation removes some of the dissolved substances, less chlorine must be added to disinfect the water.
What is the difference between coagulation and flocculation in water treatment plant?
Basically, coagulation is a process of addition of coagulant to destabilize a stabilized charged particle. Meanwhile, flocculation is a mixing technique that promotes agglomeration and assists in the settling of particles. The product of the mixing intensity and mixing time is used to describe flocculation processes.
What is coagulation process?
Coagulation is a process of combining particles, colloids, and dissolved organic material into larger aggregates (Amirtharajah and O’Melia, 1990). These aggregates are then removed from the water usually by clarification and filtration processes in most conventional WTWs.
What foods use coagulation?
Coagulation is used in food preparation most commonly for cooking eggs, some examples include; raw eggs being cooked eg boiled or scrambled as part of a dish, making a quiche with coagulated eggs, meringue (denaturation for beating the eggs, coagulation for cooking the egg product), pretty much any egg product being Mar 14, 2014
What are the steps in water treatment?
They typically consist of several steps in the treatment process. 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.
What is the most commonly used coagulant in water treatment?
Aluminum and iron salts are the most commonly used inorganic coagulants in the wastewater treatment settings. These include based aluminum metals (aluminum chloride, aluminum sulfate, sodium aluminate) and iron based metals (ferrous sulfate, ferric sulfate, ferric chloride) [13, 17, 18].
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 are the side effects of alum?
Side effects of Alum The excessive amount of alum intake may cause breathing difficulty, facial puffiness, pricking sensation & small ulcers on the skin, chest/throat tightness, and burns rarely seen in some cases.
How is chloride removed from wastewater?
At high concentrations, chloride can harm fish and plant life. But there’s no easy and affordable way to remove chloride in wastewater. It would require reverse osmosis, the same process used to produce water for laboratory use, which is technically difficult as well as costly.
Is alum a coagulant?
Alum is one of the most widely used coagulants in the water treatment industry (Benschoten and Edzwald 1990). For water and wastewater treatment, the coagulants used more frequently are the inorganic salts of aluminum.
What causes coagulation in eggs?
The coagulation is the phenomenon in which an organic liquid becomes a solid mass. This phenomenon results in the yolk and the egg white changing state to form a solid. It is caused by heating.
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.
What is the most 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.
Why is alum used in water treatment?
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 chemicals are flocculants?
A flocculants are usually organic chemicals added to wastewater to enhance flocculation, such chemicals are alum, aluminium chlorohydrate, aluminium sulphate etc.
What is the principle of coagulation?
Coagulation and flocculation are related terms describing the process of preparing colloidal materials for removing by sedimentation. Coagulation is the process used to reduce the energy forces present around particles that tend to keep them from joining together to form a larger mass.
Which are two chemicals used to purify water?
Chlorine and ozone are two chemicals used to purify water.
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.
What is an example of coagulation?
Examples of Coagulation Milk proteins coagulate to thicken the mixture that forms yogurt. Blood platelets coagulate blood to seal a wound. Pectin gels (coagulates) a jam. Gravy coagulates as it cools.
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.
Can we drink alum water?
For bad breath: Add one gram of alum and a pinch of rock salt to a glass of warm water, stir till they are dissolved, then rinse the mouth with it. Do not drink it: as it can make you nauseous. For bleeding gums, weak teeth, and dental caries: Make a paste of one gram of alum, a pinch of cinnamon and some rock salt.
Which is not example of coagulation?
Rubber plating and chrome tanning.
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.
How does flocculation work in water treatment?
How does flocculation work? Flocculation is based on a chemical process. It involves adding chemicals to the wastewater in sequence and allowing tiny solid particles to collect together in a larger mass called a floc. As a treatment of wastewater, flocculation is carried out in stages.
