Tennessee Wastewater Operator Practice Exam

The optimal pH level for maintaining methanogens is typically within what range?

1. Below 6.0

2. 6.0 - 7.5

3. 7.5 - 8.0

4. Above 8.0

The correct answer is: 6.0 - 7.5

Methanogens, which are microorganisms that produce methane as a metabolic byproduct in anaerobic conditions, thrive best in a slightly acidic to neutral pH range. The optimal pH level of 6.0 to 7.5 facilitates their metabolic processes, ensuring effective digestion and energy production. Within this range, methanogens can efficiently break down organic matter and produce biogas, which is a critical part of anaerobic digestion systems commonly used in wastewater treatment. When the pH falls below 6.0, the conditions can become too acidic, potentially inhibiting methanogenic activity and leading to a decrease in methane production. Conversely, when the pH exceeds 7.5, conditions can become more alkaline, which may also stress methanogens and hinder their performance. Maintaining the pH within the optimal range is crucial for the health of the microbial community and the overall efficiency of the treatment process.