Characterization of atmospheric ammonia emissions from swine waste storage and treatment lagoons

Abstract

Fluxes of atmospheric ammonia‐nitrogen (NH3‐N, where NH3‐N = (14/17)NH3) from an anaerobic ∼2.5 ha (1 ha = 10,000 m2) commercial hog waste storage lagoon were measured during the summer of 1997 through the spring of 1998 in order to study the seasonal variability in emissions of NH3‐N and its relationship to lagoon physicochemical properties. Ammonia‐nitrogen fluxes were measured during each season (summer, fall, winter, and spring) using a dynamic flow through chamber system. Measured lagoon physicochemical parameters included surface lagoon temperature (Tℓ°C, ∼15 cm below surface), lagoon pH, and Total Kjeldahl Nitrogen (TKN). The pH and TKN of the surface lagoon water ranged from 7 to 8 pH units, and 500 to 750 mg N L−1, respectively. The largest fluxes were observed during the summer (August 1997) (mean NH3‐N flux = 4017 ± 987 μg N m−2 min−1). Fluxes decreased through the fall (December 1997) months (844 ± 401 μg N m−2 min−1) to a minimum flux during the winter (February 1998) months (305 ± 154 μg N m−2 min−1). Emission rates increased during spring (May 1998) (1706 ± 552 μg N m−2 min−1), but did not reach the magnitude of fluxes observed during the summer. Lagoon emissions in eastern North Carolina were estimated to constitute ∼33% of total NH3‐N emissions from commercial hog operations in North Carolina based on current inventories for NH3‐N emissions published by the North Carolina Division of Air Quality, North Carolina Department of Environment and Natural Resources. The ammonia flux may be predicted by an observational model log10 (NH3‐N flux) = 0.048 Tℓ + 2.1.