Characterizing ammonia and hydrogen sulfide emissions from a swine waste treatment lagoon in North Carolina

Emissions of atmospheric ammonia–nitrogen (NH3-N, where NH3-N=(14/17)NH3) and hydrogen sulfide (H2S) from a commercial anaerobic swine waste treatment lagoon (17,150 m2 at normal liquid level) were measured over a 1-year period. Continuous simultaneous measurements were made at the lagoon using a dynamic flow-through chamber system for ∼1 week during four seasons, October–November 2004 (fall), February 2005 (winter), April 2005 (spring), and June 2005 (summer) in an effort to examine diurnal and seasonal variability, and the respective relationships of NH3-N and H2S emissions to lagoon physicochemical properties. Continuously measured lagoon physicochemical parameters include lagoon surface temperature and lagoon pH. Aqueous lagoon samples were collected daily and analyzed for total Kjeldahl nitrogen (TKN), total ammoniacal nitrogen (TAN), and total sulfide concentration. TKN, TAN, and sulfide concentrations ranged from 400–650, 360–590, and 0.1–13.0 mg L−1, respectively. For NH3-N, the largest fluxes were observed during the summer (>4200 μg N m−2 min−1). During the fall and spring, average NH3-N fluxes were 1634±505 and >2495 μg N m−2 min−1, respectively. The lowest fluxes were observed during the winter where average flux values were 1290±246 μg N m−2 min−1. Fluxes for H2S were negligible during the winter season. Average fluxes increased during the fall (0.3±0.1 μg m−2 min−1) and spring (0.5±1.0 μg m−2 min−1), and highest flux values were observed during the summer (5.3±3.2 μg m−2 min−1). The seasonal NH3-N and H2S emission factors ranged from ∼10 to ∼40 kg N AU−1 yr−1 (1 AU=500 kg live animal weight) and ∼0 to ∼0.05 kg H2S AU−1 yr−1, respectively. Generally, the lagoon emissions for H2S were ∼3–4 orders of magnitude less than NH3-N. The gas fluxes were related to various physicochemical parameters including the pH and near-surface temperature of the lagoon, and the aqueous concentration of the respective gas.