Air Sampling and Analysis Method for Volatile Organic Compounds (VOCs) Related to Field-Scale Mortality Composting Operations

Abstract

In biosecure composting, animal mortalities are so completely isolated during the degradation process that visual inspection cannot be used to monitor progress or the process status. One novel approach is to monitor the volatile organic compounds (VOCs) released by decaying mortalities and to use them as biomarkers of the process status. A new method was developed to quantitatively analyze potential biomarkers-dimethyl disulfide, dimethyl trisulfide, pyrimidine, acetic acid, propanoic acid, 3-methylbutanoic acid, pentanoic acid, and hexanoic acid-from field-scale biosecure mortality composting units. This method was based on collection of air samples from the inside of biosecure composting units using portable pumps and solid phase microextraction (SPME). Among four SPME fiber coatings, 85 μm CAR/PDMS was shown to extract the greatest amount of target analytes during a 1 h sampling time. The calibration curves had high correlation coefficients, ranging from 96 to 99%. Differences between the theoretical concentrations and those estimated from the calibration curves ranged from 1.47 to 20.96%. Method detection limits of the biomarkers were between 11 pptv and 572 ppbv. The applicability of the prepared calibration curves was tested for air samples drawn from field-scale swine mortality composting test units. Results show that the prepared calibration curves were applicable to the concentration ranges of potential biomaker compounds in a biosecure animal mortality composting unit. KeywordsAir sampling, compost gas, GC-MS, dimethyl disulfide, dimethyl trisulfide, SPME, volatile fatty acids In biosecure composting, animal mortalities are so completely isolated during the degradation process that visual inspection cannot be used to monitor progress or the process status. One novel approach is to monitor the volatile organic compounds (VOCs) released by decaying mortalities and to use them as biomarkers of the process status. A new method was developed to quantitatively analyze potential biomarkers;dimethyl disulfide, dimethyl trisulfide, pyrimidine, acetic acid, propanoic acid, 3-methylbutanoic acid, pentanoic acid, and hexanoic acid;from field-scale biosecure mortality composting units. This method was based on collection of air samples from the inside of biosecure composting units using portable pumps and solid phase microextraction (SPME). Among four SPME fiber coatings, 85 μm CAR/PDMS was shown to extract the greatest amount of target analytes during a 1 h sampling time. The calibration curves had high correlation coefficients, ranging from 96 to 99%. Differences between the theoretical concentrations and those estimated from the calibration curves ranged from 1.47 to 20.96%. Method detection limits of the biomarkers were between 11 pptv and 572 ppbv. The applicability of the prepared calibration curves was tested for air samples drawn from field-scale swine mortality composting test units. Results show that the prepared calibration curves were applicable to the concentration ranges of potential biomaker...

The Spatial and Temporal Distribution of Process Gases within the Biowaste Compost

“…Gases generated inside compost can also provide useful information about the status of the biomass decay process and could potentially be exploited to optimize and control the process. The concept of using compost gases for the non-invasive, biosecure monitoring of decay process completion has been used for disposal of potentially infectious animal carcasses [9][10][11][12][13][14][15].…”

A review of the animal disease outbreaks and biosecure animal mortality composting systems

“…Another concern was monitoring the progress and completion of the process without removing the cover. Volatile organic compounds (VOCs) were used as biomarkers of decaying mortalities (Akdeniz et al, 2011(Akdeniz et al, , 2010a(Akdeniz et al, , 2010b(Akdeniz et al, , 2009. Other researchers also recognized the importance of predicting the maturity of the biosecure composting systems.…”

GC–MS and GC–NPD Determination of Formaldehyde Dimethylhydrazone in Water Using SPME

“…Increase of SPME sampling time usually results in an increase in analyte recovery [12] and therefore improved detection limits. However, it should be taken into account that an increase in sampling time may also lead to a proportional increase in error of the quantitative method due to the limited sorption capacity of porous SPME fiber coatings [17–19].…”

“…SPME technology combines sensitive sampling and sampling preparation. SPME has been used for quantification of an increasing number of complex environmental assessment applications such as indoor air [10, 11], biological processes [12], livestock waste characterization [13], and the desorption kinetics of PAHs from soils and sediments [14]. SPME in combination with GC–MS has already shown a high efficiency for screening of volatile transformation products in soils contaminated with 1,1-dimethylhydrazine [15].…”