Performance assessment and metagenomic analysis of full-scale innovative two-stage anaerobic digestion biogas plant for food wastes treatment

Food waste (FW) is an impending issue, and its resource recovery and energy recycling have become a hotspot in the academic community. This paper presents an innovative integrated two-stage anaerobic digestion process that can enhance anaerobic digestion of food waste. The new technology is an attractive solution to resolve difficulties related to productivity and system optimization in traditional single and double-stage FW digestion processes. The study revealed that the oil extraction rate increased from 2% to 3%-4% after process improvement, and the specific biogas production of the integrated twostage biogas plant (50.2 m(3)/t) was 10.54% higher than single-stage biogas plant. Metagenome data analysis indicated that aceticlastic methanogenesis was the main route for methane production in the integrated two-stage biogas plant. Considering the short payback time (1.5 years), high net present value (11.49 million) and internal rate of return (36.97%), this biogas project was economically viable. In this context, this innovative process got through the recycling bottleneck of food waste and promoted the industrialization of anaerobic treatment of food waste. (C) 2020 Elsevier Ltd. All rights reserved.