Odorous organic gas emission characteristics from cooked food wastes during aerobic decomposition

Abstract

Emission of volatile organic compounds (VOCs) from food waste is a key trouble for surrounding residents. Herein, the VOC emission patterns from headspace (gaseous) and produced leachate (aqueous) during decomposition of cooked milk cabbage, tilapia fish, and their mixture (Mix) were investigated in self-made reactors. The average amount of gaseous VOCs from fish (2888.7 mg/kg dry matter (DM)) was higher than Mix (2152.9 mg/kg DM) and cabbage (374.2 mg/kg DM). The dominant VOCs were volatile organic sulfur compounds (VOSCs) and oxygenated VOCs, accounting for 65.8 and 32.5 %, 71.8 and 25.2 %, 39.0 and 36.7 % of total VOC yields in fish, Mix, and cabbage, respectively. From leachate, average leaching fluxes of VOCs followed the order of: Mix (2487.9 μg/(L kg) DM) > fish (2374.7 μg/(L kg) DM) > cabbage (368.7 μg/(L kg) DM). VOSCs were also the major VOCs from leachate, accounting for 87.9, 98.6, and 98.5 % of total VOCs in leachate, respectively. Lactobacillus and Weissella were the dominant genera in cabbage, while Bacteroides were dominant in fish and Mix. Physicochemical factors were significantly related to bacterial composition shifts over time. Furthermore, Lysinibacillus and Vibro were positively correlated with gaseous dimethyl disulfide, while Lactobacillus, Weissella, Savagea, Ignatzschineria, Acinetobacter, and Pseudomonas showed strong relationship with dominant gaseous and aqueous VOCs. These findings provide significant references for understanding distribution and controlling of VOCs released during cooked food waste fermentation.