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 UV_185+254 + TiO₂ > UV₂₅₄ + TiO₂ > UV_185+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 (UV_185+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.

Gaseous emissions, a side effect of livestock and poultry production, need to be mitigated to improve sustainability. Emissions of ammonia (NH₃), hydrogen sulfide (H₂S), greenhouse gases (GHGs), and odorous volatile organic compounds (VOCs) have a detrimental effect on the environment, climate, and quality of life in rural communities. We are building on previous research to bring advanced oxidation technologies from the lab to the farm. To date, we have shown that ultraviolet A (UV-A) has the potential to mitigate selected odorous gases and GHGs in the context of swine production. Much less research on emissions mitigation has been conducted in the context of poultry production. Thus, the study objective was to investigate whether the UV-A can mitigate NH₃, H₂S, GHGs, and O₃ in the simulated poultry barn environment. The effects of several variables were tested: the presence of photocatalyst, relative humidity, treatment time, and dust accumulation under two different light intensities (facilitated with fluorescent and light-emitting diode, LED, lamps). The results provide evidence that photocatalysis with TiO₂ coating and UV-A light can reduce gas concentrations of NH₃, CO₂, N₂O, and O₃, without a significant effect on H₂S and CH₄. The particular % reduction depends on the presence of photocatalysts, relative humidity (RH), light type (intensity), treatment time, and dust accumulation on the photocatalyst surface. In the case of NH₃, the reduction varied from 2.6–18.7% and was affected by RH and light intensity. The % reduction of NH₃ was the highest at 12% RH and increased with treatment time and light intensity. The % reduction of NH₃ decreased with the accumulation of poultry dust. The % reduction for H₂S had no statistical difference under any experimental conditions. The proposed treatment of NH₃ and H₂S was evaluated for a potential impact on important ambient air quality parameters, the possibility of simultaneously mitigating or generating GHGs. There was no statistically significant change in CH₄ concentrations under any experimental conditions. CO₂ was reduced at 3.8%–4.4%. N₂O and O₃ concentrations were reduced by both direct photolysis and photocatalysis, with the latter having greater % reductions. As much as 6.9–12.2% of the statistically-significant mitigation of N₂O was observed. The % reduction for O₃ ranged from 12.4–48.4%. The results warrant scaling up to a pilot-scale where the technology could be evaluated with economic analyses.