Things like used coffee ground can directly be used for mushroom cultivation, which can then be consumed at the next event. If more centralised management is preferred, the same principle can be applied with these producing companies, which exist in the meanwhile in almost every city. Further, other organic waste can be processed in small portable biogas units and biogas stored, directly used for example for cooking or compressed via another mobile gas compression unit and transported for local sale. Here innovative biogas companies could support the value generation and further conversion of residues to fertilisers etc. On fixed event locations this system can be installed into the building, like at Expo halls. We, alchemia-nova, develop similar setups for buildings and will further move towards this circular event management. Homebiogas from Israel have a cheap and easily assemblable unit.