BioCycle, July 2014, by Nora Goldstein.
http://www.biocycle.net/2014/07/15/digested-dairy-manure-to-high-end-potting-soil/

"An anaerobic digester development company launched a bagged potting soil product to utilize digested dairy manure fibers and improve long-term success of facilities....when falling rates for renewable energy and the loss of the federal Investment Tax Credit grant hit at the same time."