Which gas is produced in anaerobic digesters and can be used as a fuel?

The gas produced in anaerobic digesters that can be used as a fuel is methane. Anaerobic digestion is a biological process that occurs in the absence of oxygen, where microorganisms break down organic materials, such as food waste, manure, and sewage. During this process, organic matter decomposes, leading to the formation of biogas, which primarily consists of methane and carbon dioxide.

Methane is a potent energy source and can be captured from the digester for use as a fuel in various applications, such as cooking, heating, and electricity generation. It is also a cleaner energy alternative compared to fossil fuels, producing fewer greenhouse gas emissions when burned.

Other gases mentioned, such as propane and ethane, are typically derived from fossil fuels and not produced in significant amounts during anaerobic digestion. Carbon dioxide, although a component of biogas, is not a fuel; it is often considered a waste product in this context. Therefore, methane stands out as the correct answer due to its viability as a renewable fuel source from anaerobic digestion.