Characterizing ammonia emissions from swine farms in eastern North Carolina: Reduction of emissions from water-holding structures at two candidate superior technologies for waste treatment

摘要

Program OPEN (Odor, Pathogens, and Emissions of Nitrogen) was an integrated study of the emissions of ammonia (NH_3), odor and odorants, and pathogens from potential environmentally superior technologies (ESTs) for swine facilities in eastern North Carolina. This paper, as part of program OPEN, focuses on quantifying emissions of NH_3 from water-holding structures at two of the best ESTs and compares them with the projected emissions from two conventional lagoon and spray technologies (LSTs). The evaluated ESTs are: (1) Super Soils at Goshen Ridge; and (2) Environmental Technologies at Red Hill. The water-holding structures for these two ESTs contained no conventional anaerobic lagoon. A dynamic flow-through chamber was used to measure NH_3 fluxes from the water-holding structures at both the ESTs and at the conventional LST farms. In order to compare the emissions from the water-holding structures at the ESTs with those from the lagoons at the conventional sites under similar conditions, a statistical-observational model for lagoon NH_3 emissions was used. A mass-balance approach was used to quantify the emissions. All emissions were normalized by nitrogen-excretion rates. The percentage reductions relative to the conventional lagoons were calculated for the two ESTs. Results showed substantial reductions in NH_3 emissions at both ESTs. Super Soils had reductions of 94.7% for the warm season and 99.0% for the cool season. Environmental Technologies had slightly larger reductions of 99.4% and 99.98% for the cool and warm season, respectively. As a result of such large reductions in ammonia emissions, both technologies meet the criteria to be classified as ESTs for ammonia emissions.