REDUCTION OF GAS AND ODOUR EMISSIONS FROM A SWINE BUILDING USING A BIOTRICKLING FILTER

Animal housing can emit substantial amounts of aerial contaminants such as odorous compounds and gases. Since total ammonia and odour removal is not possible within the confined animal space, the remaining option is to remove these contaminants from the exhaust air. The air treatment at the exhaust of the building could thus play an important role in the reduction of atmospheric pollution due to swine production. Three laboratory-scale air treatment units (ATU) were developed and used to treat the air from three bench-scale pig chambers over two 4-wk trials. Methane, carbon dioxide and nitrous oxide emissions were evaluated using a gas-chromatograph while non-dispersive infrared spectroscopy and UV fluorescence techniques were used to measure ammonia and hydrogen sulphide emissions. Dynamic olfactometry was also used to predict odour emissions and the hedonic tone before and after air treatment. Gases were monitored on a continuous basis while odour emissions and hedonic tone were determined once a week. NH3 emissions were reduced by 62 to 91% and H2S emissions were decreased by 24 to 66% whereas CO2 and CH4 emissions were practically unchanged by the ATU treatment. N2O emissions were increased by 100 to 700% after the air treatment. As for odour emissions, after 4 wks of operation, a 54 to 92% reduction was observed. The N2O production as well as water consumption of the equipment are two of the elements which will be optimised during the next development stages of the system. INTRODUCTION Recent studies show that the environmental issues caused by the global expansion and the intensification of agricultural operations in the last 50 years have become extremely important (Martinez et al. 2008, Godbout and Lemay 2007). The contaminants expelled from pig barns include a number of gases, dust particles (inhalable and respirable), bioaerosols (bacteria, viruses, endotoxins, fungi) and several other volatile compounds such as ammonia (NH3) and hydrogen sulphide (H2S). In addition, an increasing importance is given to the odour nuisance associated with swine production. Thus, research in this area has become more important in recent years. Air treatment systems for pig barns may represent a part of the solution to reduce odours and airborne