Anaerobic Fermentation of Food Waste: Comparison of two Bioreactor Systems

The scope of the following work was to compare two possibilities of using organic waste materials from food industry for producing biogas, which can be further converted to heat and electricity. To efficiently convert food waste to biogas, it is necessary to choose the most appropriate process, reactor system and parameters. Therefore, fermentation experiments in two reactor types - CSTR (Continuous Stirred Tank Reactor) and FBR (Fluidized Bed Reactor) were examined. The fermentations revealed yields of 670 NL biogas/kg VS (CSTR) or 550 NL biogas/kg VS (FBR) and productivities of 3.9 NL biogas/(L*d) for CSTR and 3.4 NL biogas/(L*d) for FBR system. The average methane concentration was about 60 % CH(4) for each of both reactor type fermentations. The achieved results showed that it was possible to produce biogas by using both of the tested reactor systems. However, the FBR experiments indicated advantages concerning the process stability.