Florida Wastewater Practice Test

What effect does an increase in alkalinity have on the anaerobic digestion process?

1. It reduces efficiency

2. It has no effect

3. It enhances microbial activity

4. It creates excess gas production

The correct answer is: It enhances microbial activity

An increase in alkalinity during the anaerobic digestion process is beneficial as it enhances microbial activity. Alkalinity plays a crucial role in maintaining a stable pH level within the anaerobic digester, which is necessary for the optimal growth and activity of the microorganisms responsible for breaking down organic matter. When alkalinity levels are adequate, it helps buffer the pH against fluctuations that can arise during digestion due to the production of volatile fatty acids. These acids are generated as microorganisms break down organic material, and if they accumulate without sufficient alkalinity to neutralize them, the pH can drop, leading to inhibited microbial activity or even process failure. By maintaining a higher alkalinity, the environment becomes more favorable for a diverse range of beneficial anaerobic bacteria, which improves the overall digestion process, enhances biogas production, and leads to more efficient treatment of waste. This microbial activity is essential in achieving effective organic matter reduction and optimizing the outputs of the system.