American Water College Practice Test

Prioritizing the management of a sour anaerobic digester involves ensuring optimum feeding and mixing. This is essential because anaerobic digestion relies on a balanced environment to support the microorganisms that break down organic matter. When feeding and mixing are optimized, it creates a homogeneous environment that facilitates the digestion process and helps prevent the accumulation of volatile fatty acids, which can lead to sour conditions. Proper feeding ensures that the microbial community receives adequate and consistent substrate, while effective mixing promotes even distribution of nutrients and prevents the formation of dead zones where microbial activity could be inhibited.

In contrast, reducing chemical use, increasing water flow, and promoting aerobic processes do not directly address the inherent anaerobic conditions and specific needs of the microbial community within the digester. While those may have their roles in different contexts, they are not the primary focus when managing the sour state of an anaerobic digester. So, focusing on optimal feeding and mixing is critical in maintaining the health and efficiency of the digestion process.