Question

If pH drops below 6 in an anaerobic digester, then methane production decreases because

• A. Hydrolysis stops
• B. Methanogens are inhibited
• C. Oxygen increases
• D. Sulfates increase

Hint:

Anaerobic digestion: \[ \boxed{ \begin{aligned} \text{Optimum pH} &\approx 6.8-7.5\\ \text{Low pH} &\rightarrow \text{Methanogens inhibited}\\ \text{Methane production} &\downarrow \end{aligned} } \]

Answer 1

The Correct Option is B

Methanogenic microorganisms perform best at a nearly neutral pH (about 6.8--7.5). When the pH falls below 6, their activity is greatly inhibited, resulting in reduced methane production. Hence, \[ \boxed{\text{Methanogens are inhibited}.} \] Therefore, \[ \boxed{(B)} \]