Coagulation is one of the main processes in treating industrial wastewater and effluent. It is used to remove suspended solids, colloidal particles and other contaminants that are difficult to separate from water by conventional filtration or settlement alone.
Most industrial effluents contain fine particles, which remain suspended in water for long periods. These particles, or solids, are often electrically charged, causing them to repel one another and preventing them from naturally combining into larger, heavier particles that can be removed.
The traditional first step to achieve the removal of these suspended solids is coagulation. Coagulation is the process of neutralising those repulsing charges by addition of a strongly positively charge reagent, known as coagulants. These reagents, coagulants, can be organic, inorganic (Fe, Al, Ca) or a combination of both (combined coagulant solutions). They neutralise or destabilise the electrical charges surrounding the particles, allowing them to come together and form larger aggregates.
Puretech Environmental provides industrial effluent treatment expertise covering process assessment, plant design, installation, commissioning and ongoing maintenance. Our approach considers the characteristics of the wastewater, the pollutants requiring treatment and the technologies needed to achieve the required results.
Coagulation is typically used as part of a more comprehensive industrial effluent treatment system. Its effectiveness relies on choosing the right chemicals, controlling the operating conditions and combining the process with appropriate downstream treatment technologies.
Suspended solids in effluents can have two different origins: Organic or Inorganic. Choosing the right coagulant is essential for achieving effective industrial wastewater treatment. Different chemicals perform differently depending on the composition of the effluent, the contaminants being targeted and the required treatment results.
These particles or colloids, typically of a diameter between 0.1 and 0.01 micron, pass through very fine filters and therefore have to be removed by other methods.
Additionally, the settling velocity of colloids is measured in years per metre! This is primarily due to their size and their stability caused by the typical negative charges carried at their surface which causes repulsion in the presence of other colloids.
Choice of the right coagulant and its dosage is made according to the effluent composition; also, pH for the reaction can be adjusted to reach the optimum efficiency. At design stage, different coagulants are tested in so called “Jar tests” to validate their efficiency to precipitate the suspended solids.
Once this result has been obtained, flocculation can take place to make this particles bigger.
Coagulation enhances the effectiveness of the later treatment stages such as flocculation, sedimentation and flotation, which enables industrial facilities to achieve their objectives regarding efficient wastewater treatment and the quality of the discharge.
Puretech Environmental can help you assess your treatment needs and to determine whether coagulation or a combination of effluent treatment technologies is suitable for your application.
We deal with the evaluation of various chemical treatment methods as well as with the design and commissioning of full-scale industrial effluent treatment plants, always developing solutions tailored to your specific process and operational needs.
Contact Puretech Environmental to discuss your wastewater treatment challenges and find out how our team can help.
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