On-farm pilot-scale testing of black ultraviolet light and photocatalytic coating for mitigation of odor, odorous VOCs, and greenhouse gases

Technologies for controlling gaseous emissions of livestock is of interest to producers, the public, and regulatory agencies. In our previous lab-scale study, the use of a photocatalytic coating on surfaces subjected to black ultraviolet light reduced emissions of key odorant compounds relevant to the livestock industry. Thus, an on-farm pilot-scale experiment was conducted at a commercial swine barn to evaluate a photocatalytic coating on surfaces subjected to ultraviolet light under field conditions. A flow-through reactor was constructed with a TiO₂-based photocatalytic coating on the interior surfaces and black ultraviolet light fixtures. The reactor was deployed in a room downstream of the entire swine barn exhaust. Gas samples were collected from three sampling ports in the reactor, one at the inlet (control), the midpoint (half treatment) and the outlet (treatment). Compared to the control, significant reductions in emissions were observed for p-cresol (22%), odor (16%) and nitrous oxide (9%). A significant increase in carbon dioxide (3%) was also measured. Results show that the TiO₂-based photocatalytic coating and black UV light are effective in mitigating odor, a key VOC responsible for downwind swine odor, and one important greenhouse effect gas when subjected to swine barn exhaust.