Integrated innovative biorefinery for the transformation of municipal solid waste into biobased products

Abstract The URBIOFIN demonstration-scale plant constitutes the first integrated biorefinery for the transformation of municipal solid waste (MSW) into new biobased products and a pioneer concept for converting the current linear economy to a more circular economy in the European Union (EU). URBIOFIN, with a total budget of 15 million €, is based on the synergistic action of 16 European companies, universities and research centers, and represents nowadays the most ambitious joint public-private research initiative to create a new model for the management of the organic fraction of MSW (OFMSW). The URBIOFIN biorefinery constitutes a demo-scale plant for the transformation of OFMSW into bioblocks (bioethanol, volatile fatty acids (VFA), and biogas), biopolymers (short-chain (scl-PHA) and medium-chain polyhydroxyalkanoates (mcl-PHA)) and additives (bioethylene and biofertilizers) using a battery of innovative physical-chemical and biological processes configured in a three step approach. In the pretreatment step, MSW must be sorted into OFMSW and non-organics that will be recycled. Subsequently, a fraction of OFMSW is pretreated, hydrolyzed and fermented into bioethanol, which will be catalytically converted into bioethylene (to be used for fruit ripening applications). Alternatively, the other fraction of OFMSW can be partially converted into VFAs, which will be biologically converted into scl-PHAs or elongated with bioethanol and further bioconverted into mcl-PHAs (to be used for packaging and agriculture). Finally, the VFA-free digestate is mixed with the vinasse originated from OFMSW fermentation into bioethanol and anaerobically biotransformed into biogas. Finally, biogas is photosynthetically upgraded to biomethane (to be injected into natural gas grids) or desulfurized and bioconverted into PHAs (for packaging applications) in biogas fermenters based on type II methanotrophs under nutrient-limiting conditions. The microalgae produced during photosynthetic biogas upgrading are further converted into biofertilizer.