What type of pond receives wastewater from a secondary treatment system?

A polishing pond is specifically designed to receive effluent from a secondary treatment process, such as biological treatment operations. The primary function of a polishing pond is to further improve the quality of the treated wastewater by allowing additional natural processes, such as sedimentation and biological treatment, to take place.

In a polishing pond, sunlight and natural aeration work together to enhance the breakdown of remaining contaminants and nutrients, leading to cleaner water before it is discharged into the environment. This final step is crucial in ensuring that the effluent meets regulatory standards for water quality.

While oxidation ponds can also treat wastewater, they typically function as part of the secondary treatment process itself rather than as a final step. Similarly, storage ponds are primarily used for holding wastewater for various reasons such as flow regulation, and retention ponds are designed to manage stormwater runoff. These other types of ponds do not focus specifically on the secondary treatment by further polishing effluent to ensure its quality.