Tennessee Wastewater Operator Practice Exam

What gases are primarily produced from the organic material that settles to the bottom of a pond?

1. Methane and carbon dioxide

2. Oxygen and nitrogen

3. Hydrogen and sulfur dioxide

4. Carbon monoxide and ammonia

The correct answer is: Methane and carbon dioxide

The primary gases produced from the organic material that settles to the bottom of a pond are methane and carbon dioxide. This process occurs through anaerobic decomposition, where microorganisms break down organic matter in the absence of oxygen. During this decomposition, organic matter such as dead plant and animal material is converted by bacteria into methane, a potent greenhouse gas, and carbon dioxide, which is a natural byproduct of respiration and fermentation processes. Methane is particularly significant because it forms in conditions where oxygen is limited, such as in sediment at the bottom of ponds, marshes, or other stagnant water bodies. Carbon dioxide is also generated during this biological degradation, as organisms metabolize the organic material and release it as a waste product. The other gases listed in the choices do not typically come from the anaerobic breakdown of organic material in ponds. Oxygen and nitrogen are more associated with aerobic processes, while hydrogen and sulfur dioxide are not primary products of the decomposition of organic matter in this context. Similarly, carbon monoxide and ammonia do not represent the main byproducts of the anaerobic decomposition process found in such settings. Hence, methane and carbon dioxide are the correct answer as they accurately reflect the primary byproducts produced from organic material decomposition in a pond.