What is the BOD removal efficiency for facultative ponds?

The BOD (Biochemical Oxygen Demand) removal efficiency for facultative ponds is correctly identified as being within the range of 70-90 percent. This classification is based on the understanding of how facultative ponds function in wastewater treatment.

Facultative ponds are designed for the treatment of organic waste and operate aerobically and anaerobically. This dual function allows them to effectively break down organic matter, leading to a substantial reduction in BOD levels. The bacteria in the water utilize oxygen during the breakdown process, significantly decreasing the amount of biodegradable material present.

The observed efficiency range of 70-90 percent reflects both the pond's design and its operational conditions. Factors like temperature, retention time, and the organic loading rate can influence this efficiency, but under optimal conditions, facultative ponds consistently demonstrate an ability to remove a large percentage of BOD from wastewater. This level of efficiency is crucial in ensuring that the effluent discharged meets environmental standards and protects water quality.

Thus, the selection of this answer reflects an accurate understanding of the typical performance characteristics of facultative ponds in wastewater treatment processes.