Gasification of effluent from food waste treatment process in sub- and supercritical water: H₂-rich syngas production and pollutants management

The effluent of food waste (FWE) is generated during foodwaste treatment process. It contains high organicmatter content and is difficult to be efficiently treated. In this study, the sample was collected from a 200 t/d food waste treatment center in Hangzhou, China. Subcritical and supercritical water gasification were employed to decompose and convert FWE into energy. The effects of reaction temperature (300-500 degrees C), residence time (20-70 min) and activated carbon loading (0.5-3.5 wt%) on syngas production and the remaining pollutants in liquid residue were investigated. It was found that higher reaction temperature and longer residence time favored gasification and pollutant decomposition, resulting in higher H-2 production and gasification efficiencies. It is noteworthy that the NH3-N was difficult to be converted and removed under current experimental conditions. The addition of activated carbon was found to increase the gasification efficiency. The highest total gas yield, H-2 yield, carbon conversion efficiency, gasification efficiency, total organic carbon removal efficiency and chemical oxygen demand removal efficiency were obtained from gasification at 500 degrees C for 70 min with 3.5 wt% activated carbon. (C) 2020 Elsevier B.V. All rights reserved.