Tennessee Wastewater Operator Practice Exam

What condition must be met for denitrification to occur?

1. High oxygen concentration

2. Presence of organic carbon

3. Low temperature

4. Elevated phosphorous levels

The correct answer is: Presence of organic carbon

Denitrification is a crucial biological process in the nitrogen cycle, primarily carried out by specific bacteria that convert nitrates into nitrogen gas, which is then released into the atmosphere. For this process to effectively occur, the presence of organic carbon is essential. Organic carbon serves as an energy source for the denitrifying bacteria, enabling them to thrive and perform their function of converting nitrates into nitrogen gas. In the anaerobic conditions typically conducive to denitrification, where oxygen is limited or absent, the availability of organic carbon becomes even more critical. It provides the necessary compounds that bacteria use to carry out respiration and energy production, thereby facilitating the conversion of nitrates to nitrogen gas. Conditions such as high oxygen concentrations or elevated phosphorous levels do not promote denitrification; instead, they may lead to other processes such as nitrification. Low temperatures might slow down biological processes overall, including denitrification, but do not directly influence the fundamental requirement of organic carbon for denitrification to take place.