Tennessee Wastewater Operator Practice Exam

The AOB (Ammonia-Oxidizing Bacteria) obtain their energy primarily from which compound?

1. Nitrite

2. Nitrate

3. Ammonia

4. Phosphate

The correct answer is: Ammonia

Ammonia-Oxidizing Bacteria (AOB) play a crucial role in the nitrogen cycle, particularly in the process of nitrification. They obtain their energy primarily from ammonia. In this process, AOB oxidize ammonia (NH3) to nitrite (NO2-). This oxidation not only serves the energy needs of the bacteria but also contributes to the transformation of ammonia, which can be toxic in high concentrations, into nitrite, a less harmful form that can subsequently be converted into nitrate by other types of bacteria. Understanding the metabolic process of AOB is essential for wastewater treatment operations, as they are integral to reducing ammonia levels in wastewater. Ammonia, found in various waste products, can lead to environmental pollution if not adequately reduced. The ability of AOB to harness energy from ammonia makes them vital for effective biological treatment processes that aim to mitigate the impact of nitrogenous waste.