I named my cow Cheeky Butt in part to pay homage to her fabulous but under utilized resource (she is also rather sly). I have always made compost from manure for the vegetable fields and taken harrows out to spread the paddies into the grass. But I really want to use digested slurry for compost one day after I've utilize the gas. Its one of my life goals - to can and bake for (ample) farm hands, in a summer kitchen, the outside type, where huge pots can up sauces, pickles and such. There has been much buzz about biofuel from methane over the years...but not much action in the our part of the world.
CBC has a news clip on their website of the Toronto's Zoo plan to turn their captive's manure into biofuel. They mention that the technology is "mature" particularly in Europe. Many farms and villages in India and China and elsewhere have used methane gas for centuries, from their own or their animal`s manure to cook. It is a very simple and cheap technology profile. Larger distilleries are now emerging in India and other countries with European technologies that involve specialized anaerobic digestion that may involve transgenic bacteria as perhaps the corporate industrial solution to reep profits from a grass roots technology. We have so much to learn from small scale Asian and Indigenous technologies. Scale and context have to be considered. I think Elephants belong in Sri Lanka, not Toronto, and to justify their captivity with a "green`project" is kind of like using GE Canola grown from vanishing farmland to burn in biodiesel vehicles driven around a city. I justify keeping Cheeky Butt and Aurora Curls because I believe in a good compost, but I`d feel better about our symmetry after designing a household scale digestor that works with the anaerobic bacteria that live right here in our soil.