Best Technologies for Reducing Odor Emissions from Curtain-Sided, Deep Pit Swine Finishing Buildings

Executive Summary A three year research project was funded by the Minnesota Pork Producers Association to address the problems of odors, noxious gases and greenhouse gases produced in the popular deep pit curtain sided building. Several technologies were evaluated in pilot scale testing or laboratory testing while others were installed and monitored long term on full scale production facilities. BIOFILTRATION Odor and hydrogen sulfide emission reduction of 70%-95% were measured from a biofilter placed on a curtain pig finishing barn when the curtains were closed (during mechanical ventilation). During natural ventilation or when the curtains were open, odor and gas reduction decreased to 5%-50%. Ammonia emission reduction was very variable. OIL SPRINKLING The daily sprinkling of soybean oil inside a pig finishing curtain-sided barn using an existing " soaker " distribution system reduced the indoor concentration of NH 3 , H 2 S, and odor by roughly 30%, 20%, and 10% respectively. This technology did provide moderate to high reductions (60 to 80 %) in total dust levels inside the building. Future work with different nozzles that do not clog with the oil and water mixture is needed as well as improving the distribution of the oil-water sprinkling. OZONE AIR TREATMENT Ozone was added to a full scale finishing barn. Ozone air treatment reduced odors 25% as compared to the control barn during the cold months when the building had much less ventilation and the curtains were not open. During warm months when the curtains were providing most of the ventilation, no odor reduction was seen. The hydrogen sulfide situation was similar in that there was an improvement during the colder months (33% reduction) but not during the warmer months. Ammonia during the colder months was essentially the same and better in the control barn during the warmer months. Dust levels were reduced in the ozone treated barns. There is anecdotal evidence of improved pig health in the ozone barn. CHEMICAL ADDITION DURING PUMPOUT Hydrogen peroxide was added to finishing barn pits during agitation and pumping. Data suggest a 67% reduction in hydrogen sulfide concentrations between treatment and control. Laboratory studies showed as much as 90% reduction. DIET FORMULATION The use of Standardized ideal digestibility (SID) formulation and adding synthetic amino acids had no effect on energy and nitrogen digestibility and excretion. However, feeding the SID diet reduced slurry pH, ammonia emissions and tended to reduce hydrogen sulfide emissions during …