《Odorous VOCs released from bio-decomposition and its interaction mechanism with bacteria: Compared inter-type with intra-type household garbage》

Website: https://doi.org/10.1016/j.jclepro.2024.141523

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Abstract：

Volatile organic compounds (VOCs) and pathogens that are generated during fermentation of food waste by microorganisms have caused odor annoyance and health risks. In this work, the evolution profiles of them during aerobic decomposition of inter-type and intra-type food waste were compared in laboratory-controlled reactors for three months. The emission fluxes of VOCs reached peak on the 10th day (except fish waste), then decreased sharply until leveled off. For vegetable waste, watercress emitted higher concentrations (2.5×10⁴−2.4×10⁶ μg/m³) and emission fluxes of VOCs (5.4−508 μg•kg^-1·h^-1) than pepper and onion. While for meat waste, the emitted VOCs from fish (1.4×10⁵−8.4×10⁶ μg/m³ and 68.4−4.3×10³ μg•kg^-1•h^-1) were higher than chicken and pork. Dimethyl trisulfide (DMTS) and ethyl acetate as well as DMTS and methyl methacrylate were dominant oxygenated VOCs and volatile organic sulfur compounds in vegetable and meat wastes, respectively. The odor from the leachate was attributed to the emitted sulfur-containing compounds. The main fermented bacteria in intra-type food waste were highly similar, but differed greatly between the inter-type food waste with Lactobacillus and Comamonas as well as Peptoniphilus and Wohlfahrtiimonas as the major fermented bacteria in vegetable and meat wastes, respectively. Significant correlations between microbial community and VOCs including ethyl acetate, DMDS and 2-butanone were observed. As predicted by functional annotation of prokaryotic taxa (FAPROTAX), Lactobacillus and Bacteroides were correlated with the respiration of sulfur-containing compounds and hydrocarbon degradation, respectively, suggesting that production of VOCs was contributed mainly by bacteria communities. Pathogenicity of food waste was mainly due to Enterococcus, Proteobacteria, Mycobacterium, and Salmonella. Our results are conductive to develop countermeasures to reduce VOC emission during food waste decomposition.