Tennessee Wastewater Operator Practice Exam

Which type of gas released at treatment plants can lead to respiratory issues?

1. Carbon dioxide

2. Nitrogen dioxide

3. Mercaptan

4. Ozone

The correct answer is: Mercaptan

Mercaptan is indeed a gas that can be emitted at wastewater treatment facilities and is known for its strong odor, typically associated with rotten eggs. The presence of mercaptans in the air can lead to respiratory issues and other health problems. Exposure to mercaptans can irritate the respiratory system, causing symptoms such as coughing, difficulty breathing, and throat irritation. While carbon dioxide is a byproduct of respiration and is generally present in lower concentrations without causing immediate respiratory distress, nitrogen dioxide is a harmful gas but is more commonly associated with vehicle emissions and combustion processes rather than wastewater treatment. Ozone, although unhealthful in higher concentrations and a concern in pollution discussions, is not typically produced during wastewater treatment processes. Thus, mercaptan is the gas specifically related to treatment plants that poses a direct risk for causing respiratory issues.