Linked from
The 13 pages that link to Biogas, each with the reason it gives.
Hydrogen sulfideRelated: Biogas can contain H₂S, which corrodes equipment and must often be removed.
Anaerobic digestionRelated: It is the principal combustible product of anaerobic digestion.
MethanogenesisRelated: Methanogenesis supplies its methane component.
AnaerobicRelated: It is a useful product of anaerobic digestion.
MethanobacteriatiRelated: Methanobacteriati can contribute the methane component of biogas.