Artificial olfaction system for on-site odour measurement

Odour impacts and concerns are an impediment to the growth of the Australian chicken meat industry. To manage these, the industry has to be able to demonstrate the efficacy of its odour reduction strategies scientifically and defensibly; however, it currently lacks reliable, cost effective and objective tools to do so. This report describes the development of an artificial olfaction system (AOS) to measure meat chicken farm odour. This report describes the market research undertaken to determine the demand for such a tool, the development and evaluation of three AOS prototypes, data analysis and odour prediction modelling, and the development of two complementary odour measurement tools, namely, a volatile organic compound (VOC) pre-concentrator and a field olfactometer. This report is aimed at investors in poultry odour research and those charged with, or interested in, assessment of odour on chicken farms, including farm managers, integrators, their consultants, regulators and researchers. The findings will influence the focus of future environmental odour measurement research

Identification and prioritisation of odorants within the volatile organic compounds (VOC) emissions from tunnel ventilated broiler houses in Australia

The continued expansion in population of established cities leads to rural encroachment, this rural encroachment results in a decline in the chief barrier against malodours, that of distance. Associated to the population growth is an increased demand upon primary industries to produce greater quantities of food stuffs to satisfy the consumers. Intensive livestock practices are one of the most effective ways to produce the quantity and consistent quality of livestock produce that is in increasing demand from the general population. However the operation of most intensive livestock operations results in an environmental impact that is often difficult to monitor and assess; that of their odour output. The production of broilers (meat chickens) is one example of intensive livestock practice that is under increasing pressure to minimise the impact that it has upon the surrounding environment with respect to odour production. Understanding the emissions from intensive livestock practices is the only way to develop guidelines for operators in order to minimise or at least understand the emissions of their facilities at different production cycle times. The Australian Poultry Cooperative Research Centre (P-CRC) is funding a significant project that is investigating the odour and dust emissions from typical mechanically (tunnel) ventilated poultry houses; one of the aspects of this project is the analysis of non-methane volatile organic compounds. The NMVOC analysis will be performed by collecting pumped sorbent tubes and subsequent assay using thermal desorption - gas chromatography - mass spectrometry (TD-GC-MS) and also thermal desorption - gas chromatography-mass spectrometry and olfactometry (TD-GC-MS/O.) The simultaneous detection using mass spectrometry and olfactometry allows for the odorants within the matrix to be identified and subsequently prioritised

Non-methane volatile organic compounds predict odor emitted from five tunnel ventilated broiler sheds

Non-methane volatile organic compounds (NMVOCs) emitted from mechanically ventilated poultry sheds in similar stages (32-36d) of broiler production were measured by thermal desorption-gas chromatography/mass spectrometry (TD-GC/MS), then identified using parallel factor analysis (PARAFAC2) and the NIST11 database. Calibration models predicting odor measured by dilution olfactometry from NMVOC concentrations via orthogonal projection to latent structures (O-PLS) made good predictions (Rp2=0.83-0.87, RMSEp=137-175OU) using one to eight NMVOCs with either one or two latent variables representing odor concentration and character, respectively. Similar changes in odorant composition were observed in each sampling campaign, with samples collected early in the day more odorous and more sulfurous than samples collected later in the day. High litter moisture favored sulfur-containing odorants over alcohols, aldehydes and ketones but had little bearing on perceived odor, whereas high bird density favored alcohols, aldehydes and ketones over sulfur-containing odorants. Eight VOCs that were important predictors of odor across all sheds in order of decreasing importance were dimethyl sulfide (DMS), dimethyl trisulfide (DMTS), 2-3 butanedione, 3-methyl-butanal, 1-butanol, 3-methyl-1-butanol, acetoin, and 2-butanone. Four additional NMVOCs also influenced perceived odor although less predictably; these were n-hexane, 2-butanol, dimethyl disulfide (DMDS), and 1-octen-3-ol. All of the odorants are associated with microbial or fungal activity in the litter and manure, except n-hexane, which may originate from hexane-extracted soybean meal in the chicken feed. The organosulfides measured in this study may have arisen from the field sites as well as from the degradation of thiols captured on sorbent tubes during analysis by TD-GC/MS. © 2013 Elsevier Ltd

Stability of Volatile Sulfur Compounds (VSCS) in sampling bags - Impact of temperature

Volatile sulfur compounds (VSCs) are a major component of odorous emissions that can cause annoyance to local populations surrounding wastewater, waste management and agricultural practices. Odour collection and storage using sample bags can result in VSC losses due to sorption and leakage. Stability within 72 hour storage of VSC samples in three sampling bag materials (Tedlar, Mylar, Nalophan) was studied at three temperatures: 5, 20, and 30°C. The VSC samples consisted of hydrogen sulfide (H2S), methanethiol (MeSH), ethanethiol (EtSH), dimethyl sulfide (DMS), tertbutanethiol (t-BuSH), ethylmethyl sulfide (EMS), 1-butanethiol (1-BuSH), dimethyl disulfide (DMDS), diethyl disulfide (DEDS), and dimethyl trisulfide (DMTS). The results for H 2S showed that higher loss trend was clearly observed (46-50% at 24 hours) at 30 W C compared to the loss at 5°C or 20°C (of up to 27% at 24 hours) in all three bag materials. The same phenomenon was obtained for other thiols with the relative recoveries after a 24 hour period of 76-78% at 30°C and 80-93% at 5 and 20°C for MeSH; 77-80% at 30°C and 79-95% at 5 and 20°C for EtSH; 87-89% at 30°C and 82-98% at 5 and 20°C for t-BuSH; 61-73% at 30°C and 76-98% at 5 and 20°C for 1-BuSH. Results for other sulfides and disulfides (DMS, EMS, DMDS, DEDS) indicated stable relative recoveries with little dependency on temperature (83-103% after 24 hours). DMTS had clear loss trends (with relative recoveries of 74-87% in the three bag types after 24 hours) but showed minor differences in relative recoveries at 5, 20, and 30°C. © IWA Publishing 2013

Characterizing odorous emissions using new software for identifying peaks in chemometric models of gas chromatography-mass spectrometry datasets

The task of identifying individual compounds within complex gas chromatography - mass spectrometry (GC-MS) chromatograms is made more difficult by interferences between peaks with similar mass spectra eluting at the same time, typically against a background of chemical and electronic noise. Although chemometric techniques like parallel factor analysis and multivariate curve resolution can help to purify spectra and improve correlations with reference compounds, file incompatibilities between GC-MS acquisition software and modeling software prevent the modeled spectra from being easily compared to spectra in reference libraries. In this paper we present an enhancement to OpenChrom, an open-source software for chromatography and mass spectrometry, which implements the automated cross-matching of modeled spectra to NIST08 and NIST11 mass spectral databases. The benefits of this approach are demonstrated using a complex environmental dataset consisting of non-methane volatile organic compound emissions sampled on an Australian poultry farm. \ua9 2012 Elsevier B.V