Food waste valorization applying the biorefinery concept in the Colombian context: Pre-feasibility analysis of the organic kitchen food waste processing

Abstract

Food waste has been profiled as a potential source of added-value products and energy vectors. Nevertheless, the non-standard composition of food waste has been a bottleneck in proposing different biorefinery configurations. This paper aims to analyze organic kitchen food waste (OKFW) as a source of valuable products by applying the biorefinery concept. A compositional model was proposed considering seven food groups and the consumption trends in Colombia. Biogas and fermentable sugars were produced experimentally. Sugars were considered as feedstock for simulating two scenarios for producing bioethanol and polylactic acid. Finally, a techno-economic assessment was done. As a result, the liquid hot water treatment increases the crystallinity index by 30%, obtaining a fermentable sugar yield of 0.37 kg/kg of dry OKFW. The exhausted solid after saccharification produced 0.42 m3 of biogas/kg of exhausted OKFW. Ethanol and polylactic acid yields were 0.14 kg/kg of dry OKFW and 0.12 kg/kg of dry OKFW. Biogas use in cogeneration units can provide 13.49% and 4.29% of the total plant energy demand. Sugars concentration and downstream processing were the highest energy-demanding sections in the proposed scenarios. In conclusion, OKFW is a promising feedstock to produce added-value products in Colombia. However, biorefineries should be optimized to be robust regardless of the OKFW composition but considering the most representative fractions.