CategoryEnvironment - Air
Date Full Report Received03/27/2006
Date Abstract Report Received05/22/2008
InvestigationInstitution: Michigan State University
Primary Investigator: Melvin Yokoyama
Co-Investigators: Robert von Bernuth, Susan Hengemuehle
Funded ByNational Pork Board
The experimental results of the first year of this study clearly demonstrates that boron, in the form of boric acid and sodium tetraborate (borax) is very effective in inhibiting the emissions of ammonia and hydrogen sulfide from wastewater and manure slurries from swine facilities. Addition of either 1 % boric acid or sodium tetraborate inhibited ammonia and hydrogen sulfide emissions from wastewater and manure slurries by almost 100 % for over 7 days of incubation. However, concentrations of boric acid and sodium tetraborate as low as 0.0625 % seem to be effective, depending on whether wastewater or manure slurries are treated. Additional benefits for using boron include a reduction in malodor of the manure slurry, control of enteric pathogens, and inhibition of mold growth. Economically, reagent grade boric acid cost $16.76 per kilogram, while commercial borax is $1.77 per kilogram. While boron is not very toxic for animals, there is a very narrow range between essentiality and toxicity for different plants should boron treated swine manure be applied to field crops. However, in boron deficient soils, addition of boron to livestock manure could improve its fertilizer value. A quantitative risk assessment study should be conducted to evaluate the benefit to risk probabilities for all factors for using boron to treat swine manure slurry.