What is the correct order of treatment processes in a surface water plant?

The correct sequence of treatment processes in a surface water treatment plant begins with coagulation, followed by flocculation, sedimentation, and then filtration.

In the coagulation stage, chemicals, typically coagulants like aluminum sulfate, are added to the water to destabilize suspended particles, allowing them to clump together into larger aggregates called flocs. This is crucial because it helps improve the removal of particles that could interfere with the clarity and quality of the water.

Following coagulation, the flocculation process allows for these small flocs to grow larger as they are gently mixed in a controlled manner. This increases their size, making it easier for them to settle out during the next step.

Sedimentation is then employed, where the larger flocs settle to the bottom of a tank due to gravity. This step effectively removes most of the suspended solids from the water.

Finally, the remaining clear water undergoes filtration. This step removes any remaining particles or microorganisms that have not settled out, ensuring that the water is clean and safe for consumption.

Thus, the process flow is designed to maximize the removal of particulates and contaminants effectively, leading to a clearer and safer water supply.