In the flocculation process, flocculants, or flocculating agents are generally added to the liquid so that flocculation is promoted and smaller particles (inorganic and organic), water-stable soil aggregates, or flocs/flakes agglomerate to form larger particles or lumps in the flowing medium.
Full Answer
What is flocculation in wastewater treatment?
Flocculation is a water treatment technique in which particles combine to create bigger clusters, or flocs, which are then removed from the water. This process might happen naturally or with the help of chemical agents. It is a widespread method of wastewater treatment, stormwater treatment, & purification of drinking water.
What is the coagulant added to water During flocculation?
In Plantas piloto de tratamiento de agua ,a coagulant, such as aluminum sulfate, is added to the water during the first step of flocculation. Moreover, the negatively charged solid granules suspended in the water are neutralized by the coagulant molecules that are positively charged.
How is coagulant added to wastewater?
The wastewater must be agitated with mixers. High energy mixing is required initially to ensure that the coagulant spreads throughout the water. When flocculation is in progress the mixing energy is reduced to prevent the mass of particles from separating again. Once floc is beginning to form, a polymer chemical is added to the wastewater.
How does a flocculant work?
Once floc is beginning to form, a polymer chemical is added to the wastewater. Polymers bridge the flocculant from micro to macro flocculant, meaning that the mass of particles collecting together gets bigger. This chemical also binds the collected mass together so that it does not easily disintegrate even when the water is slightly agitated.
What is added to water for flocculation?
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.
Which chemicals are added in sewage treatment plant for the process of flocculation?
Ferric Chloride works as a flocculant and coagulant. It is versatile in the water treatment industry and is an alternative to ferric sulfate.
What step is flocculation in water treatment?
Coagulation-flocculation is a chemical water treatment technique typically applied prior to sedimentation and filtration (e.g. rapid sand filtration) to enhance the ability of a treatment process to remove particles.
How do you promote flocculation?
Water Treatment 101: 6 Tips for Improving Coagulation, Flocculation and ClarificationUse the correct polymer or coagulating chemicals. ... Keep injection point close. ... Slow mixing is good mixing. ... Velocity gradient is important. ... Keep an eye on temperature. ... Balance the velocity.
What are flocculant chemicals?
What are flocculants? 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 is flocculant made of?
The aluminum-based flocculants include aluminum sulfate, aluminum chloride, sodium aluminate, aluminum chlorohydrate, and polyaluminum chloride. The iron-based flocculants include ferric chloride, ferric sulfate, ferrous sulfate, and ferric chloride sulfate [15, 69].
What is flocculation method?
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.
Which of the following chemical is usually added in the process of coagulation and flocculation?
Answer: 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.
What are CECs in water treatment?
CECs are items detected at low levels in surface water that are expected to cause harm. Contaminants include pharmaceuticals, pesticides, industrial effluents, and personal care products.
Which of the following helps in flocculation?
By adding opposite charge electrolyte.
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.
Why does calcium cause flocculation?
Clay particles usually possess net negative charge and therefore they electrostatically attract positively charged ions, such as Ca2+ cations, which form bridges, holding the particles together. Therefore, these cations can induce flocculation of clay particles.
Inorganic flocculants
Inorganic compounds are comprised of molecules that do not contain carbon. These compounds make up some of the most widely used flocculation agents on the market.
Organic flocculants
Organic flocculants include carbon-based molecules and may be biological in nature. The following agents may represent a more efficient alternative to inorganic flocculants in some cases.