Profile of Greenhouse Gas Emissions From Swine Lagoon: Implication On the Influence of Heat Fluxes.

Anaerobic lagoons are effective and low-cost tools to treat swine manure but they are also responsible for emissions of numerous atmospheric pollutants such as ammonia, greenhouse gases, and odors. The emissions of these pollutants are controlled by the interactions between the atmosphere and the lagoon as well as biochemical and physical processes occurring within the lagoon. Thus, any study on swine operations needs to address the issue of anaerobic lagoons as a source of atmospheric pollutants and the potential for devising emission reduction techniques. Despite their relatively small size, compared to lakes or estuaries for instance, these lagoons exhibit a considerable amount of complexity due to atmospheric interactions. Therefore, the aim of this work was to examine the effect of energy partitions (sensible heat and latent heat fluxes) on the emission of greenhouse gases (GHG).  GHG (i.e., methane, nitrous oxide, and carbon dioxide) emissions from swine lagoon were monitored using a photoacoustic gas analyzer. Heat fluxes were determined from meteorological parameters obtained from sensors (e.g., barometric pressures, air and water temperatures, wind speeds, and etc.) deployed on a floating platform over the lagoon.  Based on preliminary data obtained during a one week period in February, net radiation (a combination of sensible and latent heat fluxes) at the surface of the lagoon appears to have an effect on GHG emissions, especially methane.  Methane concentrations were observed to peak during the period of high net radiation (mid-afternoon). A slight increase in CO₂ emission from the lagoon surface was also observed during the period of high net radiation.  Thus, these results are important for characterizing the thermal behavior of the lagoon leading to a better representation of processes responsible for GHG emissions.