Where composting turns organic waste into soil, anaerobic digestion turns it into energy. In a sealed digester, microbes break down food waste without oxygen and release biogas, a mixture that is mostly methane, which can be burned for cooking or used to generate power.
Who benefits most
- Hostels, hotels and canteens with steady volumes of kitchen waste.
- Hospitals and large campuses with central kitchens.
- Temples, community kitchens and food processing units.
Two products, not one
Besides gas, a digester produces digestate, a liquid slurry that can be used as organic manure. Planning for how the slurry will be used or dried is as important as planning for the gas.
Getting the design right
- Size the plant to the waste actually available, measured over a few weeks, not to an estimate.
- Feed only clean, segregated organic waste. Plastics and chemicals upset the digester.
- Plan where the gas will be used and how it will be stored safely.
- Budget for operation and maintenance, and train a named operator.
A biogas plant is a living system. Feed it well and consistently, and it will repay the effort every day.