Ko te mahi a te huakita he whakapopo i te pararopi. I tēnei mahi, ka puta te haurehu koiora – he mewaro tētahi wāhanga, he hauhā tētahi wāhanga, he hauwai tētahi wāhanga. Koia nei te momo haurehu ka puta i te ruapara me te mahi rāwekeweke parakaingaki, ā, e taea ana te huri hei pūngao hiko.
When bacteria break down organic waste, biogas is produced which is part methanol, part carbon dioxide and part hydrogen. This is the type of gas that is produced at landfills and during sewage treatment, and can be harnessed as electrical energy.