What is the purpose of a sedimentation basin in a water treatment plant?

The purpose of a sedimentation basin in a water treatment plant is to allow particles to settle out of water before further treatment. This process is critical in the treatment of water, as it helps to remove suspended solids, including dirt, silt, and other particulates present in the water. When water enters the sedimentation basin, it is typically stationary or has a very low flow velocity, enabling these heavier particles to settle to the bottom due to gravity.

This settling process is essential for improving the clarity of the water and reducing the load on subsequent treatment stages, such as filtration and disinfection. By effectively removing larger particles in this initial step, the treatment plant can enhance the efficiency of later processes, ensuring the water meets quality standards for safe consumption.

In contrast, the other options focus on functions not related to sedimentation. Cooling water, mixing chemicals, or holding water for distribution does not directly contribute to the primary removal of solids in the sedimentation process. Thus, the correct understanding of the sedimentation basin’s role in water treatment is crucial for effective water quality management.