Sustainable management of biowastes is currently a major concern in the United
States. As of 2007, the United States had over 1 million livestock and poultry
operations, 6.6% of which were dairy facilities - 69,890 dairy farms (US NASS, 2009). A
variety of methods are used to collect, store, and treat manure. As concerns over water
quality and other environmental factors increase, improved methods for manure
treatment, including anaerobic digestion, are being utilized.