Tennessee Wastewater Operator Practice Exam

What could be a consequence of high BOD levels in the influent to a facultative pond?

1. Improved algal growth

2. Adequate oxygen supply

3. Decreased water clarity

4. Increased nitrification rates

The correct answer is: Decreased water clarity

High biochemical oxygen demand (BOD) levels in the influent to a facultative pond indicate a significant amount of organic material present in the wastewater. As a result, the decomposition of this organic matter by microorganisms consumes oxygen. This increased demand for oxygen can lead to anoxic or hypoxic conditions in the pond, particularly at greater depths or during certain times of the day. One consequence of these low oxygen conditions is the impact on water clarity. In the presence of high BOD, the breakdown of organic material can lead to the proliferation of bacteria and other microorganisms, which can increase turbidity in the water. The decomposition process, along with any potential algal blooms that may occur due to nutrient overload, clouds the water and decreases clarity. Thus, decreased water clarity becomes a direct consequence of high BOD levels in the influent, affecting the overall health of the aquatic ecosystem and the functioning of the treatment process.