Hydrogen sulfide emissions from a midwestern manure slurry storage basin.

Hydrogen sulfide (H2 S) emissions from midwestern U.S. dairy lagoons are episodic and seasonal. Emissions were determined using an inverse diffusion model in conjunction with measured upwind and downwind line-averaged H2 S concentrations and turbulence. Mean daily H2 S emissions from manure stored in earthen basins was 0.97 μg m-2 s-1 (σ = 1.35 μg m-2 s-1 ). Mean live animal basis daily emission from the basins was 1.1 g d-1 hd-1 (0.84 g d-1 AU-1 ). Daily emission was modeled using the van't Hoff function with air temperature as a surrogate for slurry surface temperature and a linear function of friction velocity. The mean standard error of estimate of the model was 1.8 μg m-2 s-1 (2.0 g d-1 hd-1 , 1.6 g d-1 AU-1 ) and accounted for 60% of emissions variability. H2 S emissions were enhanced for short periods during the year when the stored slurry was loaded onto trucks for removal. Emissions from the basins were not statistically different as barn manure handling changed from flushing to scraping. More measurements are needed to verify annual emissions estimates for these manure slurry storage basins and derive emission factors for these slurry storage systems.