North Carolina Home Inspector Practice Exam

Which type of gas is commonly produced from waste in sewer systems?

1. Carbon Dioxide

2. Methane

3. Ammonia

4. Hydrogen Sulfide

The correct answer is: Methane

The common gas produced from waste in sewer systems is methane. This is primarily due to anaerobic digestion, a process that occurs in environments where oxygen is limited, such as in sewage treatment facilities and landfills. During this process, microorganisms break down organic matter, and methane is one of the byproducts of this degradation. Methane is significant in the context of sewage systems because it is a potent greenhouse gas and can be harnessed as an energy source in biogas systems. Additionally, the presence of methane in sewer systems indicates the breakdown of organic waste and the effectiveness of the anaerobic processes occurring. While other gases such as carbon dioxide, ammonia, and hydrogen sulfide may also be present in sewer systems, they arise from different processes or types of waste materials. For instance, hydrogen sulfide is generated from the breakdown of certain proteins in the absence of oxygen but is not as prevalent as methane. Understanding the production of methane in sewer systems underscores the importance of waste management and environmental considerations in these settings.