The publication focuses on the process of designing and building a small urban biogas plant in the city of Hamburg. By using exclusively discarded and reclaimed materials the design-build project ZINNERGIE explores the potential of circular concepts in urban contexts. The project was initiated by Zinnwerke e.V. and accompanied by an interdisciplinary and international team of students and tutors from various universities as well as local experts, residents and schoolchildren from the neighborhood of Hamburg Wilhelmsburg.