Characterization of atmospheric ammonia emissions from swine waste storageand treatment lagoons

Fluxes of atmospheric ammonia-nitrogen (NH3-N, where NH3-N = (14/17)NH3) fr om an anaerobic similar to 2.5 ha (1 ha = 10,000 m(2)) 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 an d its relationship to lagoon physicochemical properties. Ammonia-nitrogen f luxes were measured during each season (summer, fall, winter, and spring) u sing a dynamic flow through chamber system. Measured lagoon physicochemical parameters included surface lagoon temperature (T(l)degrees C, similar to 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 su mmer (August 1997) (mean NH3-N flux = 4017 +/- 987 mu g N m(-2) min(-1)). F luxes decreased through the fall (December 1997) months (844 +/- 401 mu g N m(-2) min(-1)) to a minimum flux during the winter (February 1998) months (305 +/- 154 mu g N m(-2) min(-1)). Emission rates increased during spring (May 1998) (1706 +/- 552 mu g N m(-2) min(-1)), but did not reach the magni tude of fluxes observed during the summer. Lagoon emissions in eastern Nort h Carolina were estimated to constitute similar to 33% of total NH3-N emiss ions from commercial hog operations in North Carolina based on current inve ntories for NH3-N emissions published by the North Carolina Division of Air Quality, North Carolina Department of Environment and Natural Resources. T he ammonia flux may be predicted by an observational model log(10) (NH3-N f lux) = 0.048 T-l + 2.1.