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Varel
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Vince H. Varel

vince.varel@ars.usda.gov

Phone: 402-762-4207

Dairy Science Microbiology

PhD, University of Illinois, Champaign-Urbana

Waste Management, microbial interactions


Dr. Varel is a microbiologist who is studying the role that microbes play in the positive and negative environmental effects related to waste management in confined animal feeding operations.  Anaerobic microbial metabolism of waste products in a closed environment leads to methane production, a valuable energy source.  However, under our current livestock production systems, it is difficult to maintain anaerobic conditions in waste products produced by cattle and swine, therefore greenhouse gases and odor are released into the atmosphere.  Nutrients and pathogens from the waste can also contaminate soils, waterways, and food products.

Current research involves controlling microbial activities in cattle and swine waste through the use of cost-effective, environmentally safe antimicrobial agents that inhibit production of offensive odors.  An expected secondary benefit from the use of these chemicals is a reduction of pathogens and release of greenhouse gases.  Solutions to control ammonia emission from waste involve inhibition of the enzyme urease, which is responsible for creating the largest pool of ammonia.

A variety of natural antimicrobial plant oils including thymol, carvacrol and linalool have been shown to be effective in inhibiting odor and green house gas emission from cattle and swine waste.  Field studies with swine waste in pits indicate thymol will reduce production of methane 93%, volatile fatty acids 100%, and  pathogens 3 log10.  Costs of these products are being evaluated.

These studies will provide critical control factors regulating microbial activities in waste environments to develop better management tools and technologies to reduce the environmental impact of modern livestock production.  


   
 
Last Modified: 07/31/2007
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