Tennessee Wastewater Operator Practice Exam

What should the VS loading rate to anaerobic digesters be?

1. Variably based on the season

2. Kept as constant as possible

3. Increased as digestion progresses

4. Decreased during maintenance

The correct answer is: Kept as constant as possible

The VS (volatile solids) loading rate to anaerobic digesters should be kept as constant as possible to ensure optimal performance of the digestion process. Maintaining a consistent loading rate allows the microbial population within the digester to acclimate and operate efficiently. When the input of organic material fluctuates significantly, it can lead to imbalances in the anaerobic conditions, adversely affecting the digestion process. A stable VS loading rate promotes steady biogas production and helps to optimize the reduction of organic matter. This consistency minimizes the risk of process instability that can result from overloading or underloading the digester, which can lead to issues such as increased retention time or incomplete digestion. Variably adjusting based on the season, increasing as digestion progresses, or decreasing during maintenance can introduce uncertainties that ultimately hinder the effectiveness of digestion and reduce the quality of the effluent. Therefore, keeping the VS loading rate as constant as possible is crucial for the efficient operation of anaerobic digesters.