The gas from sludge digestion tank is mainly composed of

The gas from a sludge digestion tank is primarily composed of Methane. Sludge digestion is a process in environmental engineering where organic matter in sewage sludge is decomposed by microorganisms in an anaerobic environment, producing biogas as a byproduct. Biogas is mainly composed of methane, along with smaller amounts of carbon dioxide and traces of other gases such as hydrogen sulfide and nitrogen.