Measurement and analysis of atmospheric ammonia emissions from anaerobic lagoons

Ammonia-nitrogen flux (NH₃-N=(14/17)NH₃) was determined from six anaerobic swine waste storage and treatment lagoons (primary, secondary, and tertiary) using the dynamic chamber system. Measurements occurred during the fall of 1998 through the early spring of 1999, and each lagoon was examined for approximately one week. Analysis of flux variation was made with respect to lagoon surface water temperature (～15 cm below the surface), lagoon water pH, total aqueous phase NH_x(=NH₃+NH₄⁺) concentration, and total Kjeldahl nitrogen (TKN). Average lagoon temperatures (across all six lagoons) ranged from approximately 10.3 to 23.3^°C. The pH ranged in value from 6.8 to 8.1. Aqueous NH_x concentration ranged from 37 to 909 mg N l^?1, and TKN varied from 87 to 950 mg N l^?1. Fluxes were the largest at the primary lagoon in Kenansville, NC (March 1999) with an average value of 120.3 μg N m^?2 min^?1, and smallest at the tertiary lagoon in Rocky Mount, NC (November 1998) at 40.7 μg N m^?2 min^?1. Emission rates were found to be correlated with both surface lagoon water temperature and aqueous NH_x concentration. The NH₃-N flux may be modeled as ln(NH₃-N flux)=1.0788+0.0406T_L+0.0015(NH_x]) (R²=0.74), where NH₃-N flux is the ammonia flux from the lagoon surface in μg N m^?2 min^?1, T_L is the lagoon surface water temperature in ^°C, and NH_x] is the total ammonia-nitrogen concentration in mg N l^?1.