1 Department of Physical Science, Southern Utah University, 351 W. Center, Cedar City, UT, 84720.
2 P.O. Box 772, Watkinsville, GA, 30677.
3 Department of Chemical and Materials Engineering, Gina Cody School of Engineering and Computer Science, Concordia University, 1455 de Maisonneuve Blvd. W, EV 2.285, Montreal, Quebec, H3G 1M8, Canada.
4 Laboratory of Applied Physical Chemistry, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, Ghent, B-9000, Belgium.

Various models have been developed to determine ammonia (NH₃ ) emissions from animal manure processing lagoons to enable relatively-simple estimations of emissions. These models allow estimation of actual emissions without intensive field measurements or "one-size- fits-all" emission factors. Two mechanisms for lagoon NH₃ emissions exist: 1) diffusive gas exchange from the water surface and 2) mass-flow (bubble transport) from NH₃ contained within the ebullition gas bubble (as it rises to the surface) produced from anaerobic decomposition of organic matter. The purpose of this research is to determine whether gas ebullition appreciably affects NH₃ emissions and therefore should be considered in emissions' models. Specifically, NH₃ mass-flow emissions were calculated and compared to calculated diffusive NH₃ emissions. Mass-flow NH₃ emissions were evaluated based on a two-film model, in connection with the acid dissociation constant of ammonium (NH₄ ⁺ ), to predict the degree of NH₃ gas saturation within the bubbles. Average daily ammoniacal nitrogen concentration [AN], pH, and measured biological gas production (ebullition) in conjunction with literature values for Henry's Law constant were used to calculate emissions from NH₃ saturation of ebullition gases. Ebullition enhancement of NH₃ surface emissions due to increased turbulence was estimated from average lagoon ebullition rates and literature values of turbulence enhancement. Ebullition enhancement of NH₃ surface emissions and ebullition mass-flow NH₃ emissions were determined to be <10 and <0.052 percent, respectively, of total NH₃ emissions. Therefore, because ebullition effects are small, they may be neglected when developing process models to estimate NH₃ emissions from water surfaces of swine manure processing lagoons. This article is protected by copyright. All rights reserved.