Massachusetts Wastewater Operator Grade 6 Practice Test

Thermophilic digestion is a type of anaerobic digestion that operates within a specific temperature range, which enhances the activity of thermophilic bacteria. The optimal temperature range for thermophilic digestion typically falls between 130 to 160 degrees Fahrenheit, but the most efficient range for digestion processes is usually cited as around 120 to 135 degrees Fahrenheit. Within this range, conditions favor the rapid breakdown of organic matter, resulting in improved biogas production and reduction of pathogens in the sludge.

Choosing 120-135 degrees Fahrenheit as the correct answer reflects the ideal conditions necessary for maximizing microbial activity associated with thermophilic digestion processes. It is during these temperatures that thermophilic bacteria thrive, leading to faster digestion rates and improved overall performance of the process.

Other temperature ranges mentioned, while possibly promoting certain microbial activities, do not represent the optimal conditions desired for thermophilic digestion and may result in decreased efficiency or less effective pathogen reduction.