What is the BTU per cubic foot value of sludge gas from a well-established digestion tank?

The BTU (British Thermal Unit) per cubic foot value of sludge gas from a well-established digestion tank is typically around 650. This value reflects the energy content of the biogas produced during anaerobic digestion, where organic matter in sewage sludge is broken down by microorganisms in the absence of oxygen.

The 650 BTU per cubic foot value indicates a high concentration of methane in the biogas, which is the primary component contributing to its energy potential. A well-established digestion tank operates efficiently, allowing the conditions for optimal microbial activity, producing a more potent and energy-rich gas.

Understanding these BTU values is crucial for sewage treatment workers, as they play a significant role in energy recovery processes, helping to determine the value of biogas as a renewable energy source, and in optimizing the operations of sewage treatment facilities. The other options represent lower energy contents, which may be typical of less efficient systems or conditions that do not foster optimal digestion, but do not align with the expected production from a well-established tank.