What is the device that collects settled water leaving the sedimentation basin?

The effluent launder is a crucial component in water treatment processes, specifically found at the sedimentation basin's edge. Its primary function is to collect the settled water, known as effluent, that has undergone the sedimentation process. As water loses its turbidity and settles the heavier particles at the bottom of the basin, the launder collects the now clarified water that flows over its edge for further treatment.

This device is designed to effectively channel the settled water away from the sedimentation basin while minimizing the disturbance of the settled solids below. This is vital for maintaining water quality and ensuring that the solids do not re-enter the effluent stream.

In contrast, the influent pipe directs incoming water to the sedimentation basin prior to treatment, while the sludge hopper collects and removes the settled sludge from the bottom of the basin. The filtration tank is used for the subsequent filtration process to remove any remaining suspended solids, but it does not collect settled water. Hence, the effluent launder is the correct answer as it specifically serves the function of collecting the treated water post-sedimentation.