Coagulationbased

Coagulation-based refers to processes and systems that rely on coagulation to destabilize suspended particles and promote their aggregation into larger, removable flocs. The concept is widely used in water treatment, wastewater treatment, and certain materials processing applications where fine particles resist separation by gravity alone.

In typical coagulation-based treatment, a coagulant is added to neutralize the surface charge of colloidal particles. This destabilizes repulsive forces and allows attractive forces to drive the formation of microflocs. A subsequent flocculation stage with gentle mixing enables these microflocs to grow into larger flocs that settle by gravity or rise by flotation and can then be removed. Efficiency depends on water chemistry (pH, alkalinity, ionic strength), coagulant type and dose, temperature, and mixing conditions.

Common coagulants include aluminum- and iron-based salts such as aluminum sulfate (alum) and ferric chloride, as well as organic polymers and polyaluminum precursors. Coagulant aids and compatibility with filtration media influence performance. In many applications, the coagulation-based step is followed by sedimentation, flotation, and filtration to achieve clarifications and pathogen reduction.

Applications extend beyond municipal drinking water and wastewater treatment to industrial effluent treatment, mining slurry clarification, food and beverage processing, and even microalgae harvesting for biomass production. Advantages include effective removal of turbidity, natural organic matter, and color; reduced filtration burden; and improved clarification. Limitations include chemical costs, sludge production, potential residual metals, and sensitivity to water chemistry.