What is the relationship between solids retention time and temperature in a thermophilic digestion system compared to a mesophilic digestion system?

In the context of thermophilic and mesophilic digestion systems, the relationship between solids retention time (SRT) and temperature is crucial for understanding the efficiency of anaerobic digestion. Thermophilic digestion operates at higher temperatures, typically between 50°C to 60°C (122°F to 140°F), compared to mesophilic digestion, which usually operates at temperatures between 30°C to 38°C (86°F to 100°F).

The key reason that thermophilic digestion requires a shorter solids retention time compared to mesophilic digestion lies in the increased metabolic activity of microorganisms at elevated temperatures. The higher temperature in thermophilic conditions accelerates the digestion process, as the thermophilic bacteria are more efficient at breaking down organic matter. This faster degradation means that the solids can be processed in a shorter period of time, reducing the overall retention time needed in the system.

Furthermore, the enhanced solubilization of organic solids and quicker biogas production in thermophilic systems contribute significantly to the need for a shorter SRT. This efficiency allows operators to achieve effective waste stabilization and biogas production without the need for extended retention times, which might be necessary in a mesophilic system where bacterial activity is comparatively slower due to the