To capture methane you require anaerobic decomposition of manure or other
organic matter. There is an EPA group that has been promoting methane
recovery systems and have been helpful with a dairy producer in my region
that is considering this technology for energy production but more
importantly odor control for anaerobically stored liquid manure.
The EPA program is called AgStar. Their direcor is Kurt Roos, contact
him at (202) 233-9041 for more info.
Area Field Crops Specialist
Cornell Cooperative Extension
60 Central Avenue
PO Box 5590
Cortland, NY 13045