From urban trash to city cash: Technologies for sustainable development of cities through the valorisation of urban organic waste in Europe

• Urban bio-waste are nested into three main categories: food waste, garden waste, others. • Both biological and chemical treatments are viable options for bio-waste valorization. • Best practices show it is possible to achieve the vision of sustainable urban development. In recent years, the rising awareness towards sustainability led to a joint multilevel effort among policy makers, stakeholders, citizens and scientific researchers to decrease the urban impact on the environment. In this context, the organic fraction of municipal solid waste (OFMSW) is definitely relevant because of its impressive amount, but also for the issues related to traditional disposal processes (i.e. landfilling). For this reason, several physical–chemical and biotechnological treatments have been implemented to solve the problem of waste storage, while producing new value. In addition, new technologies have been studied to fully exploit the potential of OFSMW, especially the material which could be easily sorted. This review aims to offer a comprehensive overview of the well-established and developing technologies for the valorisation of OFMSW, with an analysis of their benefits and drawbacks, in addition to interesting insights into the good practices already implemented in the European scenario.