Tennessee Wastewater Operator Practice Exam

What effects could excessive volatile solids have in an anaerobic digester operation?

1. Improved gas flow

2. Inhibition of microbial activity

3. Increased nutrient balance

4. Enhanced sludge stabilization

The correct answer is: Inhibition of microbial activity

Excessive volatile solids in an anaerobic digester can lead to the inhibition of microbial activity. In anaerobic digestion, microorganisms play a critical role in breaking down organic material to produce biogas. When there is an overload of volatile solids, it can result in various adverse effects on the microbial community. The microbial population has a limited ability to process high concentrations of volatile solids. When too many solids accumulate, it can lead to an imbalance in the availability of nutrients, excessive production of fatty acids, or even an increase in pH levels that might be detrimental to certain microorganisms. This inhibition can slow down the digestion process and decrease biogas production, impacting the overall efficiency of the system. This outcome is significant for operators to understand, as it underlines the importance of maintaining optimal levels of volatile solids to ensure effective anaerobic digestion and ensure that the system runs smoothly.