A wastewater treatment plant is redesigned as an ‘infinite mine’, from which the residues are used for a structural composite. The goal of the project was to make a construction material of uniform and consistent biomass waste streams, giving an impulse to reindustrializing Parkstad Limburg, former coal mining area in the south of the Netherlands. Moreover the project aim was to design a building made of the composite, illustrating the architectural possibilities of this new construction material.