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

• Published in: The Science of the total environment 2020-08, Vol.730, p.138517-138517, Article 138517
• Main Authors: Yan, Mi, Su, Hongcai, Zhou, Zhihao, Hantoko, Dwi, Liu, Jianyong, Wang, Jingyi, Wang, Runpei, Kanchanatip, Ekkachai
• Format: Article
• Language: English
• Subjects: Effluent; Food waste; Gasification; Hydrogen; Sub- and supercritical water
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2020.138517

The effluent of food waste (FWE) is generated during food waste treatment process. It contains high organic matter 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 °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 H2 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, H2 yield, carbon conversion efficiency, gasification efficiency, total organic carbon removal efficiency and chemical oxygen demand removal efficiency were obtained from gasification at 500 °C for 70 min with 3.5 wt% activated carbon. [Display omitted] •Effluent of food waste was treated via sub- and supercritical water gasification.•Effects of operating parameters on gaseous product and liquid residue were studied.•The addition of activated carbon promoted the TOC and COD removal efficiency.•The highest COD removal efficiency was 93.15% at 500 °C with activated carbon.