Evaluation of different strategies for swine house exhaust odor mitigation

Air pollution and odor nuisance are critical challenges for the sustainable development of the swine industry. Several mitigation technologies have been studied to reduce odors from swine facilities. However, existing technologies continue to face issues such as low removal efficiency, secondary pollution, and high cost, while existing practical evaluations in swine farms remain inadequate. This study evaluated six different synergistic air pollution mitigation strategies for exhaust odor from an intensive swine farm by focusing on ammonia (NH₃), volatile organic compounds (VOCs), and particulate matter (PM). The overall odor reduction and economic performance of the strategies were also assessed. The result confirmed ten dominant odorants, including p-cresol, dimethyl disulfide, hexanal, acetic acid, butanoic acid, isovaleric acid, benzaldehyde, NH₃, dimethyl sulfide, and benzene. The combination of acid scrubber and photocatalysis module (ASPM) demonstrated the highest initial odor removal effectiveness (up to 87.39 %) and removed up to 86.22 % of NH₃ and 60.26 % of PM. Economic analysis highlighted the water scrubber and biofilter system (WSB) as the most cost-effective combination, with the highest average odor reduction of 14.736 OC·USD^-1·head^-1·a^-1 while maintaining a high OC reduction of 83.05 %. Additionally, the performance of the strategies decreased over time, except for biofiltration. Overall, the synergistic deodorization technologies significantly enhanced the removal of odorants, with the ASPM and WSB combinations showing the best performance in reducing odor concentration. This study demonstrated the promising prospects of synergistic deodorization technologies and provided valuable insights into the design of efficient and economically feasible air pollutants and odor control systems for swine farms, contributing to the high-quality and sustainable development of livestock husbandry.