Release of Trace Organic Compounds during the Decomposition of Municipal Solid Waste Components

Abstract

Landfill gas contains numerous speciated organic compounds (SOCs) including alkanes, aromatics, chlorinated aliphatic hydrocarbons, alcohols, ketones, terpenes, chlorofluoro compounds, and siloxanes. The source, rate and extent of release of these compounds are poorly understood. The objective of this study was to characterize the release of SOCs and the regulated parameter, non-methane organic compounds (NMOCs) during the decomposition of residential refuse and its major biodegradable components [paper (P), yard waste (YW), food waste (FW)]. Work was conducted under anaerobic conditions in 8-L reactors operated to maximize decomposition. Refuse and YW were also tested under aerobic conditions. NMOC release during anaerobic decomposition of refuse, P, YW, and FW was 0.151, 0.016, 0.038, and 0.221 mg-C dry g(-1), respectively, while release during aerobic decomposition of refuse and YW was 0.282 and 0.236 mg-C dry g(-1), respectively. The highest NMOC release was measured under abiotic conditions (3.01 mg-C dry g(-1)), suggesting the importance of gas stripping. NMOC release was faster than CH4 production in all treatments. Terpenes and ketones accounted for 32-96% of SOC release in each treatment, while volatile fatty acids were not a significant contributor. Release in aerobic systems points to the potential importance of composting plants as an emissions source.

Emission of oxygenated volatile organic compounds (OVOCs) during the aerobic decomposition of orange wastes

“…This profile of emitted OVOCs was consistent with that of OVOCs in citrus fruit flesh (Umano et al, 2002) or juice (Buettner and Schieberle, 2001;Brat et al, 2003), with ethanol, acetaldehyde, and ethyl acetate being the predominant compounds extracted. Also, the results in the study were quite similar to previous studies, which revealed that ethanol, ethyl acetate, 2-butanone and acetaldehyde typically showed high levels in odor sources such as municipal solid wastes (Staley et al, 2006) and waste treatment facilities (Eitzer, 1995;Smet et al, 1999;Dorado et al, 2014;Lehtinen et al, 2013). As shown by Fig.…”

“…Alcohols dominated in released OVOCs and were followed by esters, ketones and aldehydes (Table 1, Fig. 2), just as those detected in citrus fruit flesh (Umano et al, 2002) and juice (Buettner and Schieberle, 2001;Brat et al, 2003) and in intermediates of aerobic metabolism of organic materials (Eitzer, 1995;Staley et al, 2006). Alcohols were also observed as major VOCs emitted from green wastes (lawn clippings, yard prunings, and food wastes, as well as green and woody wastes) (Kumar et al, 2011) and biowastes (70% garden waste, 20% kitchen waste and 10% nonrecyclable paper) (Smet et al, 1999) during the aerobic composting process.…”

“…According to Binner et al (2003), an aeration rate of about 0.25 L/(min·kg − 1 ) food wastes as used in the present study is enough to ensure aerobic conditions. The orange wastes were monitored at regular intervals until there was less than a 0.2% daily increase in cumulative CO 2 yield, as described by Staley et al (2006).…”

“…Thus, OVOCs are also major non-methane organic compounds in waste gases from various waste treatment processes including transferring (Dorado et al, 2014), landfilling (Davoli et al, 2003;Dincer et al, 2006;Tassi et al, 2009) and composting (Eitzer, 1995;Smet et al, 1999;Pierucci et al, 2005;Romain et al, 2005;Staley et al, 2006;He et al, 2010;Kumar et al, 2011;Lehtinen et al, 2013). Emission of OVOCs from these treatment facilities may not only burst into their airborne ambient levels in the neighborhood (Davoli et al, 2003;Dincer et al, 2006) and contribute to ground-level ozone formation (Kumar et al, 2011), but also trigger complaints of sensory irritation by local residents.…”

“…Many previous studies have measured the composition and production of OVOCs from laboratory-controlled composting or pilot-scale landfill using different combinations of organic wastes (Smet et al, 1999;Staley et al, 2006;Kumar et al, 2011). OVOCs are present in fleshes and juices of fruits, particularly citrus (Umano et al, 2002;Brat et al, 2003).…”