The world's largest biogas plant will co-digest manure with other
feedstocks in 11- 1 million gallon tanks. The effluent will be
applied as an inorganic fertilizer. The biogas will then be
scrubbed for BTU value and pumped into the natural gas pipeline.
"Sustainable" natural gas is taking off!

http://www.siouxcityjournal.com/articles/2006/08/04/news_business/local/8e5ea70199ca80fb862571c0000d92d6.txt

James Gabriel Duncan

BioEnergy and Sustainable Technology Society
http://grove.ufl.edu/~bests/