Pilot-Scale Testing of UV-A Light Treatment for Mitigation of NH3, H2S, GHGs, VOCs, Odor, and O3 Inside the Poultry Barn

Abstract

Poultry farmers are producing eggs, meat, and feathers with increased efficiency and lower carbon footprint. Technologies to address concerns about the indoor air quality inside barns and the gaseous emissions from farms to the atmosphere continue to be among industry priorities. We have been developing and scaling up a UV air treatment that has the potential to reduce odor and other gases on the farm scale. In our recent laboratory-scale study, the use of UV-A (a less toxic ultraviolet light, a.k.a. "black light") and a special TiO 2-based photocatalyst reduced concentrations of several important air pollutants (NH 3 , CO 2 , N 2 O, O 3) without impact on H 2 S and CH 4. Therefore, the objectives of this research were to (1) scale up the UV treatment to pilot scale, (2) evaluate the mitigation of odor and odorous volatile organic compounds (VOCs), and (3) complete preliminary economic analyses. A pilot-scale experiment was conducted under commercial poultry barn conditions to evaluate photocatalyst coatings on surfaces subjected to UV light under field conditions. In this study, the reactor was constructed to support interchangeable wall panels and installed on a poultry farm. The effects of a photocatalyst's presence (photocatalysis and photolysis), UV intensity (LED and fluorescent), and treatment time were studied in the pilot-scale experiments inside a poultry barn. The results of the pilot-scale experiments were consistent with the laboratory-scale one: the percent reduction under photocatalysis was generally higher than photolysis. In addition, the percent reduction of target gases at a high light intensity and long treatment time was higher. The percent reduction of NH 3 was 5-9%. There was no impact on H 2 S, CH 4 , and CO 2 under any experimental conditions. N 2 O and O 3 concentrations were reduced at 6-12% and 87-100% by both photolysis and photocatalysis. In addition, concentrations of several VOCs responsible for livestock odor were reduced from 26 to 62% and increased with treatment time and light intensity. The odor was reduced by 18%. Photolysis treatment reduced concentrations of N 2 O, VOCs, and O 3 , only. The initial economic analysis has shown that LEDs are more efficient than fluorescent lights. Further scale-up and research at farm scale are warranted.

Design and Testing of Mobile Laboratory for Mitigation of Gaseous Emissions from Livestock Agriculture with Photocatalysis

“…TiO 2 coating was applied in the same way as in the previous study [ 11 ]. TiO 2 coating on the pre-cut panels for the UV reactor was carried out based on an application protocol provided by PureTi (Cincinnati, OH, USA).…”

“…Only ~25% of mitigation technologies developed and tested in lab-scale have been tested in real-farm conditions. We have been scaling up the photocatalytic treatment of emissions from the lab- to pilot-scales, aiming at farm-scale readiness [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 ]. Several other research teams have also been testing UV photocatalytic technology [ 18 , 19 , 20 , 21 ] for the mitigation of gaseous emissions from livestock operations.…”

“…The photocatalytic treatment has been found to show a significant reduction in odorous VOCs even after short effective treatment times that are consistent with fast-moving ventilation air on farms [ 10 , 15 ]. Previous studies have reported the varying effect of reducing NH 3 , H 2 S, greenhouse gases, VOCs, odor, and particulate matter (PM) with UV in livestock farm conditions [ 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 ].…”

“…Only a selected few studies reported on testing UV technology on a pilot scale [ 11 , 13 , 15 ] or farm-scale [ 18 , 19 ]. For that reason, there is a lack of information on UV doses and cost to reduce odorous gases in farm-scale conditions.…”

“…In addition, depending on the wavelengths of UV light, direct exposure to the light or its by-products (e.g., ozone) generated by shorter wavelength UV (e.g., 254 nm) can be risky to workers and livestock. Our previous research showed that the intrinsically safer UV-A (365 nm) could be effective in treating NH 3 , N 2 O, ozone, selected VOCs, and odor on lab- and pilot-scales [ 11 , 12 , 13 ].…”