Intensive Animal Housing with Liquid Waste Management
Summary
Dwaine Bundy, PhD., PE
Ag and Biosystems Engineering Dept
Iowa State University
Ammonia emission from swine building utilizing liquid managed manure storage
systems is primarily emitted from the excretion of the feces and urine. The ammonia
emission from the building is less dependent upon the manure management system than
the overall management of the facility.
Removal of the liquid manure from the building has less effect of the total
ammonia emission than the management of the facility. Studies show deep pits, shallow
pits with frequent removal of manure, and under floor separation of feces and urine will
not significantly alter ammonia emission from the building. The flooring system is a
significant factor in the amount of ammonia emission from the building. Manure on the
feeding floor results in higher ammonia emission. It has been shown that partially slatted
floors normally will have a higher ammonia emission level than totally slatted floors.
Overall good hygiene such as keeping the slats dry and reducing water wastage that keeps
the floors wet. Proper ventilation will also reduce manure on the floors.
Feed additives have been found to reduce ammonia by reducing pH; however, if
reduced significantly may result in higher hydrogen sulfide. Reducing the crude protein
level of the pig diet can also reduce ammonia concentrations. Manure additives can help
reduce ammonia emissions. Pit additives have been found to reduce ammonia off the
liquid manure surface as much as 40 %; however since most of the ammonia comes from
the feeding floor the overall effectiveness is minimized.
Bio-filters have been effective in removing ammonia from the exhaust air of
mechanically ventilated swine buildings. Even though it has been shown to be effective,
the relatively high cost and maintenance of the system has limited its adoption.