What is the diameter of the clarifier in the wastewater treatment plant described?

In wastewater treatment plants, the clarifier's diameter is a critical dimension that affects its performance. It is designed to provide adequate hydraulic retention time and promote effective sedimentation of suspended solids. The selection of an 80-foot diameter clarifier indicates a balance between space efficiency and operational capacity.

An 80-foot clarifier offers sufficient surface area to support the process of gravitational settling, where denser solids settle at the bottom, while allowing for the effective removal of treated water at the surface. This size ensures that the system can handle the expected influent flow rates and solids loading, crucial for maintaining optimal performance in the treatment process.

In contrast, the other dimensions provided do not align with the design parameters that would typically optimize the clarification process in a plant of this nature, which is why they are not the correct choice. A clarifier that is either larger or smaller may result in inefficient functioning, possibly leading to issues such as shorter retention times or inadequate settling, which would compromise the overall treatment efficacy. Understanding these operational specifics is vital for ensuring that wastewater treatment goals are met effectively.