Methane emissions from swine lagoons in Southeastern US

Concentrated animal production can have a significant effect on the atomospheric environment. Methane (CH4) emissions from two swine waste holding lagoons were determined periodically in 1997 and 1998. Emission rates from the lagoons were measured under ambient conditions with little disturbance to the natural environment. One farm (NC10) used a periodic 'flush' to remove wastes (8 h cycle). The second farm (NC20) used a 'pull-plug' system with a I week cycle time. In general, flux rates followed a diurnal pattern with greater fluxes during the day when both temperature and windspeed were greatest. Methane emissions from the lagoons were related to windspeed, effluent temperature and volatile solid loading into the system. Average emissions from NC10 ranged from 20 to 115 kg CH4 ha(-1) per day. Greatest emissions were during the spring period when the sludge depth was deepest. Emissions from NC20 were much less (5.3-10.7 kg CH4 ha(-1) per day) due primarily to fewer number of animals and type of manure handling system. Emissions followed a diurnal pattern with greatest emissions during the day when effluent temperature was greatest. The average flux for the year from the two lagoons were 62 and 8 kg CH4 ha(-1) per day which corresponded to 6.0 and 1.6 kg CH4 per animal per year, respectively. (C) 2002 Elsevier Science B.V. All rights reserved.