Biogenic Emissions from Green Waste and Comparison to the Emissions Resulting from Composting Part II: Volatile Organic Compounds (VOCs)

The cumulative emissions of volatile organic compounds (VOCs) resulting from natural decay of selected green waste, i.e. grass clippings, woodchips and prunings, and from composting of the same feedstock were studied. The results indicated that terpenes were the only compounds emitted from the feedstock as they underwent natural breakdown as well as during their composting. Even though there was a wide array of compounds emitted, the results suggested that the following six terpenes i.e., α-pinene, β-pinene, 3-carene, camphene, β-myrcene, and D-limonene, were the most significant compounds encompassing 32.7 to 95.3% of the total emissions. The cumulative VOC emissions varied considerably from a batch to another ranging 11.0 to 347.4 mg/kg-dw expressed as α-pinene. The composting of the same materials in different blends resulted in cumulative emissions ranging from 18.1 to 106.6 mg/kg-dw as α-pinene, representing 60 to 92% reduction compared to the biogenic emissions resulting from natural decay.