Turning manure into methane gas that can be used as an energy source has the potential to generate revenue in livestock producers' businesses, create jobs and generally bolster communities, scientists and legislators say.
Speaking at the "Manure to Methane Symposium" held Nov. 1-2, Richard Nelson, director of Engineering Extension at Kansas State University, says that with total world and U.S. energy consumption projected to rise by 58 and 40% respectively by 2025, it's important that scientists, industries, and governments actively pursue the development and implementation of renewable energy resources which provide for energy security, environment enhancement, and economic well-being. The use of waste by-products such as livestock manures for alternative energy production is a prime example.
The process of turning manure into methane (biogas) requires the use of a methane digester. An anaerobic digester is a closed container with conditions favorable to anaerobic microorganism growth, where a carbon containing, biologically active product (manure or waste) is held long enough to allow the microorganisms to use the nutrients and energy available. The energy they release may then be captured and used.
A Dallas-based company, The Panda Group, in September announced that it will build a 100-million-gallon ethanol plant in Haskell County, Kan., powered by manure from Haskell and surrounding counties' livestock operations.
Reduced odors, production of a gas that can be used in various ways and still having manure at the end of the process with most nutrients intact, including nitrogen and phosphorus, are benefits of turning livestock manure into biogas, says Jeff Lorimor of Curry-Wille and Associates, based in Ames, Iowa.
But biogas production is not a good fit for all livestock operations, Martin says. Very small operations may not produce the volume needed to justify the expense. The process requires a substantial capital investment, as well as operating and maintenance costs. Running a digester also requires frequent collection of manure that includes minimal foreign material.
He described the AgSTAR Program, a voluntary effort sponsored by the U.S. Environmental Protection Agency (EPA), the U.S. Department of Agriculture, and the U.S. Department of Energy. The program encourages the use of methane recovery (biogas) technologies at confined animal feeding operations that manage manure as liquids or slurries. Information about the AgSTAR Program is available at www.epa.gov/agstar.