By the end of 2023, biowaste must be completely separated or recycled at source, based on EU legislation. Separate biowaste collection and valorisation for biofuels could play an essential role in the biobased circular economy. In this context, the principal goal of this paper was to demonstrate on a pilot scale the technological solution of bioethanol production via the utilisation of urban source-separated biowaste within the city context of Athens, Greece. More specifically, the main aim was the demonstration of a pilot system for more than 10 consecutive operating cycles with real feedstock—wet; separately collected biowaste. From the 11 pilot trials performed with wet feedstock, the mean starch and cellulose degradation of the pilot trials amounted to 80.69 ± 16.27% and 79.41 ± 10.37%, respectively, while the bioethanol yield was 74.05 ± 6.82%. The latter was comparable to that of more intensive pretreatment methods. Homogenization and shredding, which were applied in this study, stand as promising pretreatment methods for bioethanol production from wet feedstock. Further research is needed to optimize conditions and evaluate scalability. Nevertheless, pilot-scale testing is a crucial step in the deployment of this technology since it serves as a bridge between laboratory research and full-scale implementation, offering a practical and controlled environment to validate and optimize the technology while minimizing risks and uncertainties. Conclusively, this study could stand as a flagship case study for the implementation of circular and sustainable approaches in the management of organic fractions of source-separated municipal waste, showcasing the technical feasibility of the whole value chain from waste collection to final bioethanol product recovery.

By the end of 2023, biowaste must be completely separated or recycled at source based on the EU legislation. Separate biowaste collection and valorisation towards biofuels could play an essential role in the biobased circular economy. In this context, the principal goal of this paper was to demonstrate in pilot scale the technological solution of bioethanol production via the utilisation of urban source-separated biowaste within the city context of Athens, Greece. More specifically, the main aim was the demonstration of a pilot system in continuous operation (over 10 operating cycles) with real feedstock – wet separately collected biowaste. From the 11 pilot trials performed with wet feedstock, the mean starch and cellulose degradation of the pilot trials amounted up to 80.69±16.27% and 79.41±10.37% respectively, while the bioethanol yield was 74.05±6.82%. The latter was comparable to that of more intensive pretreatment methods. Homogenization and shredding that was applied in this study, stand as promising and cost-effective pretreatment methods for bioethanol production from wet feedstock. Further research is needed to optimize conditions and evaluate scalability. Nevertheless, pilot scale testing is a crucial step in the development and deployment of this technology since it serves as a bridge between laboratory research and full-scale implementation, offering a practical and controlled environment to validate and optimize the technology while minimizing risks and uncertainties.