Continuous Amonia and Hydrogen Sulfide Emission Measurements Over A Period of Four Seasons From A Central Missouri Swine Lagoon

Abstract

The purpose of this research was to determine the influence of seasonal periods and environmental parameters including effluent temperature, air temperature, relative humidity, wind speed, and effluent concentration of hydrogen sulfide (H2S) and ammonia (NH3) on emission of H2S and NH3 from a central Missouri swine lagoon with a total surface area of 7,800 m2. The flux rate of H2S and NH3 was monitored semicontinuously for a period of four seasons using a nonintrusive, micrometeorological method. Emission rate of NH3 and H2S from the lagoon followed a predictable gaussian line shape with maximum emissions occurring in late July to early August. The maximum emission of NH3 from the lagoon was measured at 125.6 kg * day-1 (277 lbs * day-1), while maximum H2S emissions were 14.1 kg * day-1 (31 lbs * day-1). Emission models based on effluent temperature, pH, wind speed, and relative humidity were tested for their ability to predict the variability in emission rate of NH3, H2S, and the sparingly soluble gases, methane (CH4) and carbon dioxide (CO2). Effluent analysis data (NH3-N and H2S-SH) for NH3 and H2S was used to select an emission testing period when effluent concentration of NH3 and H2S remained essentially constant in the lagoon. Multi-component models based on effluent temperature, wind speed, and relative humidity for this sampling period could predict up to 91% of the variability in emission of the sparingly soluble gases, CH4 and CO2. However, under the same conditions, these models could only predict up to 64% of the variability in H2S emissions and up to 54% of the variability in NH3 emissions. These results indicate that there are considerable mechanistic differences that drive emission rate of sparingly soluble (CH4 and CO2) and polar, soluble (NH3 and H2S) gases from the animal effluent environment.