Ammonia emissions and hydrogen sulfide levels during handling of manure-laden drying bed material in a high-rise~(TM) hog facility

摘要

Concentrations of ammonia and hydrogen sulfide within the exhaust air from a 960-head, High-Rise~(TM) swine finishing facility were monitored during cleanout of the facility, and emission rates were calculated from these measurements. Ammonia concentrations of exhaust air from individual fans ranged from undetectable to 39 ppm during the June cleanout period. The average ammonia concentration of exhaust air from the fans did not increase as a result of handling manure in the building. As time wenton and the cleanout progressed into quadrants with less-enriched material, ammonia concentrations subsided and distribution of ammonia within the building and exhaust air became more uniform. When the last set of readings were taken, the majority of fanswere exhausting air with less than 5 ppm of ammonia. Relatively small concentrations of H_2S (0.4 ppm and traces) were detected in the exhaust of a couple of fans during handling of material in June. In contrast to ammonia, hydrogen sulfide concentrations were higher in November than in June. Hydrogen sulfide was detected (> 0.2 ppm) in the exhaust of 10 of the 15 operating fans with a maximum reading of 3.6 ppm. Downwind ammonia concentrations were higher during cleanout of this facility than during the production phase, but the concentrations appeared likely to have subsided below detectable levels by the time the material in the last quadrant was moved. Ammonia could only be measured (>= 0.25 ppm) 30.5 m downwind of the building when the first quadrant was being cleaned out in June. Total unit emission rates of ammonia ranged from 21.0 to 37.0 mg/min/pig space or 23.8 to 41.8 mg/min/m~2.