No abstract

Concentrated livestock feeding operations have become a source of odorous gas emissions that impact air quality. Comprehensive and practical technologies are needed for a sustainable mitigation of the emissions. In this study, we advance the concept of using a catalyst for barn walls and ceilings for odor mitigation. Two catalysts, a new TiO 2 -based catalyst, PureTi Clean, and a conventional Evonik (formerly Degussa, Evonik Industries, Essen, Germany) P25 (average particle size 25 nm) catalyst, were studied for use in reducing simulated odorous volatile organic compound (VOC) emissions on a laboratory scale. The UV source was black light. Dimethyl disulfide (DMDS), diethyl disulfide (DEDS), dimethyl trisulfide (DMTS), butyric acid, p-cresol, and guaiacol were selected as model odorants. The effects of the environmental parameters, the presence of swine dust covering the catalyst, the catalyst type and layer density, and the treatment time were tested. The performance of the PureTi catalyst at 10 µg/cm 2 was comparable to that of P25 at 250 µg/cm 2 . The odorant reduction ranged from 100.0 ± 0.0% to 40.4 ± 24.8% at a treatment time of 200 s, simulating wintertime barn ventilation. At a treatment time of 40 s (simulating summertime barn ventilation), the reductions were lower (from 27.4 ± 8.3% to 62.2 ± 7.5%). The swine dust layer on the catalyst surface blocked 15.06 ± 5.30% of UV 365 and did not have a significant impact (p > 0.23) on the catalyst performance. Significant effects of relative humidity and temperature were observed.

Control of gaseous emissions from livestock operations is needed to ensure compliance with environmental regulations and sustainability of the industry. The focus of this research was to mitigate livestock odor emissions with UV light. Effects of the UV dose, wavelength, TiO2 catalyst, air temperature, and relative humidity were tested at lab scale on a synthetic mixture of nine odorous volatile organic compounds (VOCs) and real poultry manure offgas. Results show that it was feasible to control odorous VOCs with both photolysis and photocatalysis (synthetic VOCs mixture) and with photocatalysis (manure offgas). The treatment effectiveness R (defined as % conversion), was proportional to the light intensity for synthetic VOCs mixtures and followed an order of UV185+254 + TiO2 > UV254 + TiO2 > UV185+254; no catalyst > UV254; no catalyst. VOC conversion R > 80% was achieved when light energy was >~60 J L−1. The use of deep UV (UV185+254) improved the R, particularly when photolysis was the primary treatment. Odor removal up to ~80% was also observed for a synthetic VOCs mixture, and actual poultry manure offgas. Scale-up studies are warranted.

Aerial emissions of odorous volatile organic compounds (VOCs) are an important nuisance factor from livestock production systems. Reliable air sampling and analysis methods are needed to develop and test odor mitigation technologies. Quantification of VOCs responsible for livestock odor remains an analytical challenge due to physicochemical properties of VOCs and the requirement for low detection thresholds. A new air sampling and analysis method was developed for testing of odor/VOCs mitigation in simulated livestock emissions system. A flow-through standard gas generating system simulating odorous VOCs in livestock barn emissions was built on laboratory scale and tested to continuously generate ten odorous VOCs commonly defining livestock odor. Standard VOCs included sulfur VOCs (S-VOCs), volatile fatty acids (VFAs), and p-cresol. Solid-phase microextraction (SPME) was optimized for sampling of diluted odorous gas mixtures in the moving air followed by gas chromatography-mass spectrometry (GC-MS) analysis. CAR/PDMS 85μm fiber was shown to have the best sensitivity for the target odorous VOCs. A practical 5-min sampling time was selected to ensure optimal extraction of VFAs and p-cresol, as well as minimum displacement of S-VOCs. Method detection limits ranged from 0.39 to 2.64ppbv for S-VOCs, 0.23 to 0.77ppbv for VFAs, and 0.31ppbv for p-cresol. The method developed was applied to quantify VOCs and odorous VOC mitigation with UV light treatment. The measured concentrations ranged from 20.1 to 815ppbv for S-VOCs, 10.3 to 315ppbv for VFAs, and 4.73 to 417ppbv for p-cresol. Relative standard deviations between replicates ranged from 0.67% to 12.9%, 0.50% to 11.4%, 0.83% to 5.14% for S-VOCs, VFAs, and p-cresol, respectively. This research shows that a simple manual SPME sampler could be used successfully for quantification of important classes of odorous VOCs at concentrations relevant for real aerial emissions from livestock operations.

Commercial manufacture of fruit leathers (FL) usually results in a portion of the product that is out of specification. The disposition of this material poses special challenges in the food industry. Because the material remains edible and contains valuable ingredients (fruit pulp, sugars, acidulates, etc.), an ideal solution would be to recover this material for product rework. A key practical obstacle to such recovery is that compositing of differently colored wastes results in an unsalable gray product. Therefore, a safe and scalable method for decolorization of FL prior to product rework is needed. This research introduces a novel approach utilizing ozonation for color removal.To explore the use of ozonation as a decolorization step, we first applied it to simple solutions of the commonly used food colorants 2-naphthalenesulfonic acid (Red 40), tartrazine (Yellow 5), and erioglaucine (Blue 1). Decolorization was measured by UV/vis spectrometry at visible wavelengths and with a Hunter colorimeter. Volatile and semivolatile byproducts from ozone-based colorant decomposition were identified and quantified with solid phase microextraction coupled with gas chromatography-mass spectrometry (SPME-GC-MS). Removal of Yellow 5, Red 40 and Blue 1 of about 65%, 80%, and 90%, respectively, was accomplished with 70 g of ozone applied per 1 kg of redissolved and resuspended FL. Carbonyl compounds were identified as major byproducts from ozone-induced decomposition of the food colorants. A conservative risk assessment based on quantification results and published toxicity information of potentially toxic byproducts, determined that ozone-based decolorization of FL before recycling is acceptable from a safety standpoint. A preliminary cost estimate based on recycling of 1000 tons of FL annually suggests a potential of $275,000 annual profit from this practice at one production facility alone. ABSTRACT: Commercial manufacture of fruit leathers (FL) usually results in a portion of the product that is out of specification. The disposition of this material poses special challenges in the food industry. Because the material remains edible and contains valuable ingredients (fruit pulp, sugars, acidulates, etc.), an ideal solution would be to recover this material for product rework. A key practical obstacle to such recovery is that compositing of differently colored wastes results in an unsalable gray product. Therefore, a safe and scalable method for decolorization of FL prior to product rework is needed. This research introduces a novel approach utilizing ozonation for color removal. To explore the use of ozonation as a decolorization step, we first applied it to simple solutions of the commonly used food colorants 2-naphthalenesulfonic acid (Red 40), tartrazine (Yellow 5), and erioglaucine (Blue 1). Decolorization was measured by UV/ vis spectrometry at visible wavelengths and with a Hunter colorimeter. Volatile and semivolatile byproducts from ozone-based colorant decomposition were identified and quantified with solid...

Industry-standard Tedlar bags for odor sample collection from confined animal feeding operations (CAFOs) have been challenged by the evidence of volatile organic compound (VOC) losses and background interferences. Novel impermeable aluminum foil with a thin layer of fluorinated ethylene propylene (FEP) film on the surface that is in contact with a gas sample was developed to address this challenge. In this research, Tedlar and metallized FEP bags were compared for (a) recoveries of four characteristic CAFO odorous VOCs (ethyl mercaptan, butyric acid, isovaleric acid and p-cresol) after 30 min and 24 hr sample storage time and for (b) chemical background interferences. All air sampling and analyses were performed with solid-phase microextraction (SPME) followed by gas chromatography-mass spectroscopy (GC-MS). Mean target gas sample recoveries from metallized FEP bags were 25.9% and 28.0% higher than those in Tedlar bags, for 30 min and 24 hr, respectively. Metallized FEP bags demonstrated the highest p-cresol recoveries after 30-min and 24-hr storage, 96.1 ± 44.5% and 44.8 ± 10.2%, respectively, among different types of sampling bags reported in previous studies. However, a higher variability was observed for p-cresol recovery with metallized FEP bags. A 0% recovery of ethyl mercaptan was observed with Tedlar bags after 24-hr storage, whereas an 85.7 ± 7.4% recovery was achieved with metallized FEP bags. Recoveries of butyric and isovaleric acids were similar for both bag types. Two major impurities in Tedlar bags' background were identified as N,N-dimethylacetamide and phenol, while backgrounds of metallized FEP bags were significantly cleaner. Reusability of metallized FEP bags was tested. Implications: Caution is advised when using polymeric materials for storage of livestock-relevant odorous volatile organic compounds. The odorants loss with storage time confirmed that long-term storage in whole-air form is ill advised. A focused short-term odor sample containment should be biased toward the most inert material available relative to the highest impact target odorant. Metallized FEP was identified as such a material to p-cresol as the highest impact odorant from confined animal feeding operations. Metallized FEP bags have much cleaner background than commercial Tedlar bags do. Significantly higher recoveries of methyl mercaptan and p-cresol were also observed with metallized FEP bags. IntroductionIn recent decades, intensive large-scale livestock production has grown rapidly in the United States and other parts of the world. The large number of animals raised in concentrated animal feeding operations (CAFOs) can affect air quality by emissions of odor, volatile organic compounds (VOCs), NH 3 , H 2 S, greenhouse gases (GHGs), and particulate matter (PM) (National Research Council [NRC], 2003;Heber et al., 2006aHeber et al., , 2006bJacobson et al., 2008;Hoff et al., 2009). Air pollution and odor nuisance are a major challenge for livestock production (NRC, 2003;Kim et al., 2007;Parker et al., 2012;Cai et al., 20...

The commercial production of fruit leathers results in some material that is not to specification. Although this product remains edible and contains valuable ingredients such as fruit pulp, sugars and acidulates, it is not salable and its disposal is costly. Because these products are typically highly colored, recovery of fruit leather for recycling into the product requires colorant removal to avoid an unappetizing brownish color from the mixture of colorants. This research introduces a novel approach utilizing ozonation for color removal. The treatment was first applied to pure solutions of the commonly used food colorants 2-naphthalenesulfonic acid (Red 40), tartrazine (Yellow 5), and erioglaucine (Blue 1). Color removal was measured by UV/Vis spectrometer, and a Hunter colorimeter. Byproducts from ozone-based colorant decomposition were identified and quantified with SPME-GC-MS. Removal of Yellow 5, Red 40 and Blue 1 was about 65%, 80% and 90% complete, respectively, with 70 g ozone applied to 1 kg aqueous fruit leather suspension solution. Given the known structures of these dyes, a concern with this approach is the potential formation of toxic ozonolysis byproducts. In initial work, carbonyl compounds were identified as major byproducts. Among these, benzaldehyde, 2-furfural, ethanal and hexanal were identified as byproducts of known toxicity at levels sufficient for concern. A head-space solid-phase microextraction (HS-SPME) method with on-fiber derivatization using o-(2,3,4,5,6pentafluorobenzyl)hydroxylamine hydrochloride (PFBHA) was optimized for detection and quantification of carbonyl compounds in ozonated fruit leather suspensions. Ethanal, hexanal, furfural and benzaldehyde were quantified with the newly developed method, and detection limits were in the range of 0.016-0.030 µg/L. For furfural, the ozonolysis byproduct noted in the literature as having the highest median lethal dose value, the maximum amount generated

Fruit leathers (FLs) production produces some not-to-specification material, which contains valuable ingredients like fruit pulp, sugars and acidulates. Recovery of FL for product recycling requires decolorization. In earlier research, we proved the efficiency of an ozone-based decolorization process; however, it produces carbonyls as major byproducts, which could be of concern. A headspace solid-phase microextraction with on-fiber derivatization followed by gas chromatography-mass spectrometry was developed for 10 carbonyls analysis in ozonated FL solution/suspension. Effects of dopant concentration, derivatization temperature and time were studied. The adapted method was used to analyze ozonated FL solution/suspension samples. Dopant concentration and derivatization temperature were optimized to 17 mg/mL and 60 °C, respectively. Competitive extraction was studied, and 5 s extraction time was used to avoid non-linear derivatization of 2-furfural. The detection limits (LODs) for target carbonyls ranged from 0.016 and 0.030 µg/L. A much lower LOD (0.016 ppb) for 2-furfural was achieved compared with 6 and 35 ppb in previous OPEN ACCESS Chromatography 2015, 2 2 studies. Analysis results confirmed the robustness of the adapted method for quantification of carbonyls in recycled process water treated with ozone-based decolorization. Ethanal, hexanal, 2-furfural, and benzaldehyde were identified as byproducts of known toxicity but all found below levels for concern.