Material flow analysis of an upgraded anaerobic digestion treatment plant with separated utilization of carbon and nitrogen of food waste

• Published in: Bioresource technology 2024-08, Vol.406, p.131005, Article 131005
• Main Authors: Zhao, Chuyun, Yang, Luxin, Chen, Ziqi, Wu, Chunxu, Deng, Zhou, Li, Huan
• Format: Article
• Language: English
• Subjects: Carbon–nitrogen separation; Kitchen waste; Mass flow; Phosphorus; Protein degradation
• ISSN: 0960-8524; 1873-2976; 1873-2976
• DOI: 10.1016/j.biortech.2024.131005

[Display omitted] •Food waste anaerobic digestion based on nitrogen-carbon separation was investigated.•Three-phase separation redistributed carbon and nitrogen before anaerobic digestion.•78.4% of C and 48.3% of N in food waste were separated in the centrifugation.•The main endpoints for C, N, and P are crude oil, fine slag, and biogas slag.•Separation utilization of carbon and nitrogen improve resource recovery level. Anaerobic digestion of food waste can recover carbon in the form of biogas, while the high concentration of ammonia nitrogen in the digestion effluent becomes troublesome. Therefore, some new treatment plants use three-phase centrifugation to separate homogenized food waste into nitrogen-rich fine slag for insect cultivation and carbon-rich liquid for anaerobic digestion. To analyze the effects of the carbon–nitrogen separation, an upgraded plant’s material and elementary flows were investigated. The three-phase separation process redistributed carbon and nitrogen, and the biogas slurry was the primary output. The principal endpoint for C was the crude oil, capturing 57.1 ± 13.1 % of the total input; the find slag collected 48.3 ± 6.9 % of the total N input, and the biogas slag accepted 52.9 ± 4.4 % of the P input. The carbon–nitrogen separation strategy can improve digestion efficiency and increase treatment benefits significantly, marking a promising direction for future developments in food waste utilization.