Laboratory scale evaluation of volatile organic compound emissions as indication of swine carcass degradation inside biosecure composting units

Abstract

Biosecure livestock mortality composting systems have been used to dispose of diseased livestock mortalities. In those types of system, visual inspection of carcass degradation is not possible and monitoring VOCs (volatile organic compounds) released by carcasses is a new approach to assess progress of the composting process. In this study, field-scale livestock mortality composting systems were simulated and a laboratory scale composting system with aerobic and anaerobic test units was designed to collect VOC samples from the headspace of decaying plant materials (70 g dry weight) and swine tissues (70 g dry weight) at controlled operating temperatures. Headspace samples were collected with SPME (solid phase microextraction) and analyzed by a GC-MS (gas chromatography-mass spectrometry) system. Among the 43 VOCs identified, dimethyl disulfide, dimethyl trisulfide, and pyrimidine were found to be marker compounds of the mortality composting process. These compounds were only found to be produced by decaying swine tissues but not produced by decaying plant materials. The highest marker VOC emissions were measured during the first three weeks, and VOCs were not detected after the 6th week of the process, which indicates degradation processes were completed and compost materials microbially stabilized (no additional VOC production). Results of respiration tests also showed that compost materials were stabilized. Results of this study can be useful for field-scale composting operations but more studies are needed to show the effects of size and aeration rate of the composting units.

Performance of a plastic-wrapped composting system for biosecure emergency disposal of disease-related swine mortalities

“…The chemical composition of the pine shavings used in this study suggests a possible explanation. Work by Akdeniz et al (2010a) on VOCs released during composting reported that several terpenes (e.g., camphene, limonene, β -pinene, β -phellandrene) were detected in mortality compost that employed pine shavings. These compounds, which have antimicrobial properties (Dermirci et al, 2007, Imelouane et al, 2009Leite et al, 2007), may have been made more available by wetting the shavings, thereby suppressing microbial activity and heat production.…”

“…Results of the VOC study are reported in papers by Akdeniz et al (2010aAkdeniz et al ( , 2010bAkdeniz et al ( , 2011.…”

Mitigation of Livestock Odors Using Black Light and a New Titanium Dioxide-Based Catalyst: Proof-of-Concept

“…The concentrations of odorant VOCs in the standard generated gases were calculated as a ratio of the standard mass injected for each compound and the airflow ( Table 2). The resulting concentrations ranged from 4.32 to 888 ppb, i.e., they were within the range of concentrations measured inside livestock barns [37]. The photocatalysis treatment of the gaseous odorant VOCs took place in a 200-mL flow-through UV reaction chamber in a standard gas generation (SGG) system ( Figure 1, Figure S1).…”

“…The selection of target odorants was based on the reported chemical emissions from typical swine barns [37]. A special setup for generating a dynamic (moving) gas mixture was designed, assembled, and tested, using the procedure described by Koziel et al [38] and by Akdeniz et al [39].…”

Assessment of compost maturity by using an electronic nose

“…Feedstocks are considered the most important factor in determining what particular intermediate and potentially compounds develop Büyüksönmez et al, 2012). Additional managing factors such as temperature, O 2 levels, humidity, pH and duration of composting are also of significance (Akdeniz et al, 2010;Blazy et al, 2014;Büyüksönmez and Evans, 2007;Delgado-Rodríguez et al, 2012b;Romain et al, 2005).…”