Flocculation and flotation techniques play an indispensable role in treatment plants, as they help to remove contaminants and guarantee water quality, both for use in industrial activities and for human consumption.
In this article, you will see what are the similarities and differences between these processes, how they are carried out and the types of substances applied to each of them. Check it out!
Flocculation is a water treatment process carried out through the addition of flocculating agents that agglutinate fine particles suspended in the liquid. In this way, they make up larger particles called flakes, which are deposited at the bottom of the sedimentation tank or float on the surface of the water, facilitating their removal.
Flotation, on the other hand, uses chemical reagents to create air bubbles, which bind to the waste and cause it to rise to the surface of the water. Thus, a layer of foam forms that can be removed more easily.
Flocculation and flotation serve to remove substances that cannot be separated from water by conventional filtration processes. In the case of flocculation, we can mention wastes such as:
In addition to those already mentioned, floating also allows the removal of:
For this reason, flocculation and flotation are applied in various segments of the industry, such as:
The most common flocculating agents are aluminum, iron, and polymer salts. One of the main examples is aluminum sulfate, whose chemical formula is Al2 (SO4) 3. When added to water together with calcium oxide (CaO), it forms a gelatinous substance called aluminum hydroxide (Al (OH) 3), to which the impurities stick.
Another common flocculating agent is ferric chloride (FeCl3), which is used in more acidic waters. Polymers, such as polyacrylamide and chitosan, are often used to make the process more efficient and faster.
The most common floating reagents are pine oil, cresol, and alkylphenols. As we already mentioned, they are added to water to create air bubbles that bind to suspended particles and cause them to rise to the surface.
In addition, coagulating agents, such as aluminum sulfate and ferric chloride, can be added to aid in the floating process.
One of the advantages of flotation is that it can be used in waters with a high concentration of suspended solids and remove even smaller particles than the flocculation process. On the other hand, it may be more expensive, since it requires the use of special equipment, such as floating tanks and specific air systems.
Flotation can be easily adapted to different water types and treatment levels, and is divided into two types:
In dissolved air flotation, the flotation reagents are added to the water and the air is dissolved in it under pressure. The mixture is then released into a floating chamber, where a cloud of small bubbles forms that adhere to the suspended particles and carry them to the surface, where they can be removed.
In induced air floating, air is introduced into the water through an agitation or turbulence system, creating air bubbles that bind to suspended particles. This method tends to be used in smaller scale applications, such as wastewater treatment from laboratories and small industries
Because it is a highly complex job, it is necessary to have specialized support to ensure maximum efficiency, both in the flocculation and flotation processes and in the other water treatment stages.
It is also essential to verify that the supplier's practices are aligned with the guidelines of the ISO 9001 standard, which attest to the application of the most stringent quality and safety standards.
To learn more about the subject, continue with us and see the essential criteria for choosing an industrial water treatment company.
