Futures grow in cities.
In this modern world, one can barely survive a day without coffee while the pressure at work is increasing. Since the past decade meeting up to have a cup of coffee contributed to maintain social contact between friends. Therefore, drinking coffee has become a daily habit for people. The consumption of coffee produces in the canton of Zurich over 13,000 kg of coffee ground daily which mostly ends up as waste in the compost. Based on the privately financed and developed underground freight transport system called ‘Cargo Sous Terrain’ (CST) which will be built by 2030 in Zurich, the wheat which was in the past transported via the cargo train above ground is no longer needed anymore. The underground tunnel system allows for a noiseless, CO2 emission friendly and fluent transport of the wheat for Swissmill. Thus, the tower as a temporary wheat storage is no longer in need and creates with its characteristics the optimal environment to let mushrooms and mycelium grow on coffee ground.
One way to reuse the coffee ground and produce energy from it was designed by Gassner, Vogel, Heyen and Maréchal who developed the system of hydrothermal gasification. On top of that, according to BAFU (Bundesamt für Umwelt) coffee ground is one of the most environmentally harmful food. Another way to reuse coffee ground is by injecting it with spores and grow mushrooms on it since the soil still contains a lot of usable nutrients. Normally 25% wood chips are added to 75% of coffee ground to create the required soil mixture. Instead of wood chips, which are not available locally, wheat waste from the graining process of Swissmill is used. Next to the production of mushrooms, mycelium which is the vegetative body of mushrooms can grow on a mixture of 25% of coffee ground and 75% of wheat waste, vegan bacon can be produced for Zurich inhabitants. Generally, drinking coffee daily will always be present, thus coffee ground will always be produced, and therefore, the potential to reuse it for local food production and producing energy for the people.
