Characteristic analysis for odor gas emitted from food waste anaerobic fermentation in the pretreatment workshop

Abstract

Gas chromatography–mass spectrometry, olfactometry, and other related methods were applied for the qualitative and quantitative analysis of the characteristics of odorous gases in the pretreatment workshop. The composition of odorous gases emitted from municipal food waste was also investigated in this study. The results showed that the tested gases are mainly composed of aromatic gases, which account for 49% of the total volatile organic compounds (VOC) concentrations. The nitrogenous compounds comprise 15% of the total concentration and the other gases comprise the remaining 36%. The level of odor concentration ranged from 2523 odor units (OU) m−3 to 3577 OU m−3. The variation of the total chemical composition ranged from 19,725 µg m−3 to 24,184 µg m−3. Among the selected four sampling points, the discharge outlet was detected to have the highest concentration in terms of odor, total chemical, sulfur compounds, and aromatics. The correlation analysis showed that the odor concentrations were evidently related to the total chemical composition, sulfur compounds, and aromatics (P < 0.05, n = 5). The odor activity value analysis identified the top three compounds, hydrogen sulfide (91.8), ethyl sulfide (35.8), and trimethylamine (70.6), which contribute to air pollution complaint of waste materials. Implications: Currently, the amount of food waste has rapidly increased, which leads to difficulty in waste management and more odorous gases released as air pollution. In processing of food wastes by anaerobic fermentation, odorous gases are generated, which significantly affect the workers and occupants in the plant. In the pretreatment workshop for anaerobic decomposition, the odorous gases are generated because of the stacking and decomposition of food wastes. The gases emitted mainly consist of organic gases because the food wastes are mainly organic materials. The other odors that comprise 1% of the gases are S-compounds, aromatics, esters, alkanes, and limonene, which result in unpleasant odors that are harmful to the health.