Building a Biogas Digester: turning food waste into cooking gas and fertiliser

Led by an interdisciplinary team of students, the initiative provides practical sustainability education through hands-on workshops and research. The digester will supply cooking gas and fertilizer to the Test Site and nearby areas, including Otaniemi Urban Garden and potentially flowerbeds in collaboration with ACRE (Aalto University Campus & Real Estate). The project group also partner with Aalto Foodsharing to source organic waste.

"Small-scale biogas production enables local re-use of waste and decreases dependence on centralised energy production and industrial fertilisation. The workshop offers sustainability education to a larger group of people with practical ways of capturing energy locally. It also challenges our notion of what “waste” is and how it can be used and recycled as a source of valuable material. A direct experience of transforming food waste into cooking gas offers a shift of mindset where a problem is turned into a resource. Using the gas for cooking decreases the need to use other sources of energy. 

Creating energy and recycling waste are crucial steps towards community-based self-sufficiency and resilience in a post-fossil future. Biogas digestion is a circular solution that returns nutrients from food back to the soil whilst creating and storing energy in the process. Biogas digesters are a simple and affordable but not yet a common home solution. We want to promote learning on the topic by offering an open lecture and the practical experience of building a digester taught by an expert. Through scientific research we acquire relevant information about the digestion process that we also wish to share to other people using biogas, and therefore supporting a development of home biogas systems beyond our own experiment."