The 4-year DECISIVE –A DECentralised management Scheme for Innovative Valorisation of urban biowastE– Project co-funded by the European Commission, under the Horizon 2020 programme and led by ISTREA has been finalized reaching the end of its implementation phase after 62 months. The two main reasons to extend the duration of the action from initial the 48 months were the COVID and the change of the demonstration site from Catalonia to Dolina. Despite the deviations, the project made satisfactory progress and provided results that are excepted to likely produce significant potential impact in the future.

The Decision Support Tool (DST) for planning a decentralized system of urban biowaste valorisation was designed. Its final version is available here. The micro–Anaerobic Digestion (mAD) and the Solid-State Fermentation (SSF) processes were designed, and their prototypes constructed. The mAD prototype of 100 L was constructed and operated with good performance. Finally, the creation of a green economy model through the DECISIVE concept was studied addressing key features of a green economy at local level.

The beneficiaries disseminated and communicated project’s activities and results by scientific publications, conferences, two patent application submissions, the website, workshops attended and delivered, videos, etc.

ENT led the development of the DST and the simulation of theoretical and real demonstration sites for testing the final version of the web-tool. Nine theoretical sites and two real ones (Lyon and Dolina) were selected from the initial list of 18 European locations to verify the capabilities and the practical use of the DST. For each location, a baseline scenario was created, along with an alternative one, with the use of the DECISIVE concept. For small cities it was assumed to handle biowaste only with the DECISIVE concept and technologies while for big cities or regions only a small part of waste was supposed to be handled with the DECISIVE technologies as complementary technologies to the current ones. Results obtained from the DST on the theoretical demonstrations indicated a better performance of the DECISIVE system in relation to transport intensity and time requirement for sorting, and lower performance in electricity recovery. Thus, the use of a DECISIVE system is more of value in dispersed areas with low population, in areas with a dense matrix of large food waste producers, or where the great quality of biowaste can eliminate the pre-treatment step.

The project studied the impact of the changes in the bio-waste management system in quality and quantity before and after the decentralized system implementation. Results showed a higher quality of bio-waste source separated in food services and commercial activities than in households. Moreover, a significant part of organics is still present in the residual waste and sorting and prevention communication has a key role on quality of separately collected bio-waste. These results can be used for useful recommendations such as that bio-waste sorting and valorisation has to be completed by a coordinated communication. Moreover, prevention has to specifically target the avoidable fraction of food waste that is high in present waste collection systems. Project results showed that decentralized and low-capacity installations for bio-waste management can be flexible, addressing treatment problems connected to quality and quantity fluctuations. Moreover, large treatment installations are usually not reluctant to novel complementary technologies with better environmental performance. There is a need for further exploration of the system design that prioritizes local demands and supply chains while safeguarding the environment. Moreover, in microscale systems, close collaboration and sharing proved to be essential and vital for the success.