Try driving I-10 going east into El Paso, TX some day, as I did about a year and a half ago. You travel through, and smell the effluvia of, at least ten miles of feed lots strung along the interstate. Something like this might be feasible there and do a lot for the travelers who have to run the gauntlet.
Another thing we found, is that methane digesters are extremely dangerous. Storage is a real problem.