Tennessee Wastewater Operator Practice Exam

What condition can indicate issues with a digestor process in a wastewater treatment facility?

1. Excessively low pH

2. High levels of ammonia

3. Low dissolved oxygen

4. High temperature fluctuations

The correct answer is: High levels of ammonia

High levels of ammonia can indicate issues with the digestion process in a wastewater treatment facility. Ammonia is a byproduct of the decomposition of organic matter, and its elevated levels in the digester suggest that the microbial population responsible for breaking down organic material may be imbalanced or stressed. This imbalance can occur due to various factors, such as insufficient nutrient levels or improper operating conditions, like temperature or retention time. In effective digestion, ammonia is normally converted into nitrogen gas or taken up by biomass. Therefore, a build-up of ammonia often points to a disruption in the digestion process, indicating that the system is not functioning optimally. Monitoring ammonia levels is crucial for operators to ensure the digesters are performing effectively and to take corrective measures if necessary. The other conditions mentioned can also affect the digestion process, but they do not directly relate in the same way to ammonia levels as indicators of underlying issues specific to the digestion of organic material.