LAUSR

Hydrogen sulfide (H2 S) emissions from Midwestern United States diary anaerobic waste lagoons are episodic and seasonal. Emissions were modeled using an inverse diffusion model in conjunction with measured concentrations and turbulence. The potential for lagoon mixing was estimated by the Brunt-Vȁisȁlȁ frequency using a theoretical Fourier series temperature profile model constructed from measured air and lagoon temperatures. Annual H2 S emissions from the dairy parlor and holding area liquid waste, based on 318 days of measurement, were 212 g m-2 or 807 g hd-1 (hd = head of cattle). H2 S emissions were highest in the spring and the fall. Eleven days with emissions were greater than 7 g d-1 hd-1 accounted for 25% of the annual emissions. Shear mixing appeared to dominate the mixing in the lagoon when the lagoon was estimated to be nearly isothermal. Wind shear correlated with significantly greater daily mean emissions. H2 S emissions of this lagoon appeared to result from a series of processes; biogenic production of H2 S in the sludge, H2 S-enriched bubbles rise through the lagoon by buoyancy and wind shear induced mixing, and bubbles bursting at the surface either due to desiccation of the bubbles or surface disturbances induced by wind and precipitation. This article is protected by copyright. All rights reserved.