Flocculants are used to help in eliminating materials suspended in water in a wide range of industries. In this blog, we will elaborate on the complete role of flocculants in wastewater treatment, explaining what flocculants are, how they work and for what purpose they are used. The blog will also differentiate how flocculants are different from coagulants, which is another wastewater treatment class of chemicals.




What is Flocculation?

Generally, flocculation is the elimination of sediment from a fluid as it is the segregation of a solution. The term is taken from the word floc, meaning material flakes; the sediment has shaped into larger aggregated flakes when a solution is flocculated, which makes them more uncomplicated to see and eliminate. The flocculation process happens naturally, or it can also be compelled to utilize physical processes and/or flocculants.

Flocculation Process and its Stages

Flocculation is generally a chemical process that involves the addition of chemicals to the wastewater in sequence, permitting tiny solid particles to accumulate together. Flocculation is conducted in four different stages.

Stage 1

A coagulant like aluminum sulphate is added to the wastewater in the first stage. Coagulant molecules that are positively charged neutralize the negatively charged solid particles dangled in the water. Dangled solid particles in wastewater are charged negatively. Neutralizing these substances cover the way for them to flocculate together into a larger mass.

Stage 2

The wastewater must be perturbed with mixers. Initially, high energy mixing is needed to make sure that the coagulant increases throughout the wastewater. The energy used for mixing is reduced when flocculation is in progress to stop the particles’ mass from segregating again.

Stage 3

A polymer chemical is added to the wastewater once a floc starts to form. The mass particles collect together to get bigger as polymers bridge the flocculant from micro to macro. The mass is also collected together by this chemical to make it tough for disintegration even when the water is slightly perturbed.

Stage 4

The large solid masses can be eliminated from the wastewater stream after flocculation is accomplished. This is accomplished through the use of filters that, in the filter material, capture the floc or through settling where the floc drops to the bottom for elimination. When cleaning the filters, care must be taken to ensure that the phosphorus-rich floc is treated and contained.

What are Flocculants?

Flocculants are materials that promote the aggregation of the fine particles present in a solution generating a floc which then sets into the bottom of the liquid (sedimentation) or floats to the surface of the fluid (flotation). Using this method makes it easier to eliminate fine particles from the liquid.

Flocculants might be inorganic or organic, and they come in various forms, charge densities—molecular weights and charges. Organic polymeric flocculants because of their ability to advance flocculation with a relatively low quantity.

However, their lack of biodegradability and the linked dispersion of possibly dangerous macromolecules into water deliveries is the reason for shifting to biopolymers that are more eco-friendly.

The issue with these is they need a higher quantity than organic polymeric flocculants and have a shorter shelf-life. Combined solutions are being developed to fight this, where on natural polymers, synthetic polymers are grafted to create customized flocculants for wastewater treatment that offer the best advantages of both.

Use of Flocculants

Many different industries across the world are using flocculants, and they are used in different industries from biotechnology, earth sciences, and civil engineering companies to cheesemakers and breweries.

However, flocculants are mainly utilized for water clarification, sludge thickening, solids dehydration, solids removal, and lime softening in the wastewater treatment industry. Water can have colloidal solids, like bacteria, decaying plant material, plankton, clay particles or many other organic substances.

Using flocculation and coagulation has been an active practice to purify water since 2000 BC when almonds smeared was used around the vessels to purify river water by the ancient Egyptians.

Flocculation leading to sedimentation is utilized for the refinement of drinking water and industrial wastewater treatment, stormwater, and sewage. Due to it, flocculants are widely known plant chemicals utilized for water treatment.

How do Flocculants work?

Flocculants can be executed on their own or in connection with coagulants relying upon the chemical composition and charge of the solution needed to be separated. Coagulants operate by weakening the present particles in the solution, permitting them to make bonds with flocculants and causing them to be aggregate.

The flocculants then gather the particle in floc form, and once they are floated to the surface, they are separated, or when they accumulate in the bottom, they are removed from the water.

The proper combination of inorganic or organic coagulants and flocculants will rely on the type of substances needed to be eliminated from the water and the separation method being utilized by the water treatment facility (i.e. floatation or sedimentation etc.)

Difference between Coagulants and Flocculants

Both the processes are common as both are used for wastewater purification and treatment, but still flocculation and coagulation are different processes in many ways. Coagulation used for water treatment and purification is a chemical process whereby the solution’s chemical properties are changed to lead coagulation.

Coagulation means to curdle, and the same process is initiated with coagulation which naturally occurs in milk when the liquid’s pH changes and the milk solids cluster together. Coagulants are generally salts that break down to liberate negative or positive charges.

On the other hand, flocculation is a physical process that first forms a cloud and then a precipitate, causing fine particles to floc together for easy removal and water treatment. Often polymers or macromolecules are the flocculants, including settling fine particles into flocs or larger flakes.

Other techniques or physical agitation are often needed to lead to flocculation; on the other hand, as soon as the coagulant is added to the solution, coagulation will occur without any need for physical processes for running the process.

Flocculants are constantly an essential part of the water treatment process. For further information regarding wastewater treatment and flocculants, you can ask the experts team members or search out more on our website for further details.

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