Gaseous emissions in municipal wastes composting: Effect of the bulking agent

• Emission factors for MSW and organic fraction of MSW composting have been determined.
• Polyethylene tube has been compared to wood chips as bulking agent.
• Use of polyethylene tube as bulking agent reduces NH3, CH4 and VOC emissions.
• Alpha and beta pinene emissions are related with wood bulking agents.
• Terpenes are predominant VOC in all the processes, being limonene the most abundant.

In this study, the emissions of volatile organic compounds (VOC), CH4, N2O and NH3 during composting non-source selected MSW, source selected organic fraction of municipal solid wastes (OFMSW) with wood chips as bulking agent (OF_wood) and source selected OFMSW with polyethylene (PE) tube as bulking agent (OF_tube) and the effect of bulking agent on these emissions have been systematically studied. Emission factors are provided (in kg compound Mg−1 dry matter): OF_tube (CH4: 0.0185 ± 0.004; N2O: 0.0211 ± 0.005; NH3: 0.612 ± 0.269; VOC: 0.688 ± 0.082) and MSW (CH4: 0.0549 ± 0.0171; N2O: 0.032 ± 0.015; NH3: 1.00 ± 0.20; VOC: 1.05 ± 0.18) present lower values than OF_wood (CH4: 1.27 ± 0.09; N2O: 0.021 ± 0.006; NH3: 4.34 ± 2.79; VOC: 0.989 ± 0.249). A detailed composition of VOC is also presented. Terpenes were the main emitted VOC family in all the wastes studied. Higher emissions of alpha and beta pinene were found during OF_wood composting processes.