Urban bio-waste valorization – resource evaluation and characterization for energy recovery by anaerobic digestion.
Résumé
Source separation will help divert fermentescible organic wastes, in particular from landfilling and incineration. In agreement with the European Directives, the French Energy Transition for Green Growth Act (TECV, 2015) has set a series of objectives with respect to waste prevention and bio-waste valorization. In many urban areas however, the efficiency of source separated collection often remains relatively poor, in particular for urban biowaste. The environmental quality of bio-waste is strongly affected by the presence of several undesirable fractions, including in some cases hazardous domestic waste, making it difficult to recycle organic matter for agricultural purposes. Energy recovery on the other hand is less demanding in terms of biowaste quality, and appears more adapted to urban bio-wastes. However, with the exception of the MBT projects for the treatment of residual MSW, there is still little industrial feedback on the process of urban bio-waste conversion to methane. A new strategy to treat urban bio-waste could be the production of a single energy vector, methane. This fuel can indeed be produced using proven technologies: anaerobic digestion and methane production for liquid and easily fermentescible fraction, and thermochemical process combining gasification and methanation of syngas to treat solid fraction diverted to the mean stream. The objective of this work was to characterize bio-waste streams produced in an urban territory, with regards to their potential use as feedstock for anaerobic digestion.