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How do coagulation and flocculation help remove small particles from water?
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wastewater treatment
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In water treatment, coagulation and flocculation are essential processes used to remove small, light particles that are otherwise too slow to settle out of suspension on their own.1
The Process
- Coagulation: Chemicals known as coagulants, such as aluminum sulfate (alum), are added to the water during a rapid mixing stage. This ensures the chemicals are dispersed evenly to initiate a reaction that destabilizes the particles.1
- Flocculation: Following rapid mixing, the water undergoes a period of gentle, slow agitation. This process encourages particle collisions, allowing them to aggregate into larger, heavier masses called floc.1
By increasing the size and weight of these particles, the process enables them to be effectively removed during the subsequent sedimentation stage. While flocculation creates these loose aggregations, it is important to note that these flakes are delicate and can be easily disrupted if the agitation is not carefully controlled.12