Emission of volatile organic compounds during aerobic decomposition of banana peel

Abstract

Emissions of volatile organic compounds (VOCs) were continuously measured during the aerobic decomposition of banana peel in a laboratory-scale landfill simulator over 25 d. Using direct membrane inlet single-photon ionisation time-of-flight mass spectrometry (MI-SPI-ToF-MS), 18 VOCs belonging to 10 functional groups were detected in the air samples, and their VOC emission profiles were established using cluster analysis on time-resolved data. Three emission stages were clearly identified, with the major release for most VOC compounds occurring during the first 14 d. The emission patterns of the individual compounds were quite similar despite the different release mechanisms. In addition, no apparent increase in temperature was observed inside the simulator during the entire experimental period. We suggest that the volatilisation of the constituents in the waste pile contributed equally to VOC emissions as did the degradation of banana peel via microbial activity. The average emission rate of total VOCs reached 44.3 × 10^-3 mg VOC kg^-1 of dry banana peel, with more than half belonging to malodourous substances. The malodourous emissions of the decaying banana peel in an aerobic environment mainly originated from styrene, dimethyl sulphide, and diethyl sulphide, the most common contributors to offensive odourants during food waste biodegradation.

Keywords: Biodegradation; MI-SPI-ToF-MS; Malodourous emissions; Simulated aerobic landfill; Time-resolved characterisation.