Partitioning of ammonia and hydrogen sulfide emissions into pit and wall exhaust fractions for a deep-pit pig finishing barn

Ammonia and hydrogen sulfide emissions were measured from a 2000-head tunnel-ventilated deep-pit pigfinishing bam in southern Minnesota for 45 days during August and September 2004. Additional pit ventilation was added to one side or 1000 head room of the double-wide building to test whether the higher pit ventilation rate would result in a reduction in wall fan emissions along with an improvement in the indoor air quality. Biofilters are starting to be used on pig bams in Minnesota to treat pit exhaust air to reduce odors and other hazardous gases being emitted from these buildings. Results of the study revealed that 70% of the NH₃ and 76% of the H₂S emissions from a room (north) with a pit ventilation rate of 13 m³/s (27 cfin/pig), which is a common design for Midwestern pig bams, are from the pit exhaust stream. The south bam, operating with a pit ventilation rate of 13 m³/s during the night (7 PM to 7 AM) and 20 m³/s (43 cfm/pig) during the day (7 AM to 7 PM), emitted 75% of the NH₃ and 81% of the H₂S emissions through the pit fans. The results of this shortterm study indicates that additional pit ventilation has little or no significant effect on wall fan emissions of NH₃ and H₂S, and did not improve indoor air quality inside the building.