Operators should, as a rule, never change the temperature in an anaerobic digester by more than how many degrees Fahrenheit per day?

In anaerobic digestion, maintaining a stable temperature is crucial for ensuring optimal microbial activity. The microorganisms responsible for breaking down organic matter in anaerobic digesters thrive within specific temperature ranges. If the temperature fluctuates too greatly, it can disrupt the metabolic processes of these microbes, potentially leading to reduced digestion efficiency or even system failure.

Changing the temperature by no more than 1 degree Fahrenheit per day is recommended to minimize shocks to the microbial community. This gradual approach allows the microorganisms to acclimate to temperature changes, thereby maintaining their activity levels and promoting effective gas production and organic matter breakdown.

Greater temperature changes, such as those reflected in the other options, could create environments that are too stressful for the microbes, possibly leading to reduced bioactivity or die-off. Therefore, adhering to the standard of limiting temperature adjustments to 1 degree Fahrenheit per day helps ensure the stability and health of the anaerobic digestion process.