There are hundreds of feedlots in Texas and New Mexico which all have disposal problems with the tons of manure accumulating weekly. A few use heaped composting under tarps to recycle some of the stuff but making biomethane is the very best disposal because it generates a marketable byproduct. My eyes always burn as I pass them by due to the waste products; this wouldn't happen using digesters. OTOH, there isn't much incentive to spend the money since air emissions aren't regulated for the ag industry in those states.