New Digester Opportunities —
Studying Digester Feasibility for Mid-Sized Dairy Farms

Anaerobic digestion technology holds many benefits for Minnesota farms. It has the potential to reduce environmental problems associated with animal agriculture and provide economic benefits to farms and rural communities. It can reduce odor, pathogens, greenhouse gas emissions, costs for bedding by utilizing recycled solids and adds value by producing renewable energy which provides distribution generation of electricity. 

However, most of the commercially developed anaerobic digester technology has been proven to be most economically feasible on dairy farms that have 300 or more cows. But according to the 2002 Census of Agriculture, 96% of Minnesota's dairy farms have 200 cows or less. This brings into question if there is a possibility that 96% of Minnesota's dairy farms can receive the same economic and environmental benefits from anaerobic digester technology that larger farms can?

Through funding provided by AgStar Fund for Rural America, the Minnesota Project was able to contract with Philip Goodrich to complete a preliminary report assessing existing digester systems appropriate for small to mid dairy farm size. Mr. Goodrich has over 30 years of experience in the field of anaerobic digester systems. The report he prepared contains information about six digester models that could be applied for use on small to mid-sized dairy farms. Each model contains information dealing with the schematics of the system, an explanation of how the system functions, environmental benefits, and lessons learned from other similar digesters. Capital costs for the installation of the digesters and yearly costs are presented. 

Report available: Anaerobic Digester Systems for Mid-Sized Dairy Farms 740kb pdf.

Report summary from BioCycle Magazine, November 2005, 1.15mb pdf.

Minnesota Pilot Demonstration. Through partial funding from the Natural Resources Trust Fund as recommended by the Legislative Commission on Minnesota’s Resources, the Minnesota Project is partnering with a Minnesota dairy farm and other project partners to study the effectiveness of a modified anaerobic digester system on a dairy farm with 50-300 cows. It is anticipated that this project will demonstrate a digester design specifically for small dairy farms that maximize the potential for on-farm economic benefits of manure.

About the Legislative Commission on Minnesota’s Resources

The function of the LCMR is to make funding recommendations to the legislature for special natural resource projects. These projects help maintain and enhance Minnesota’s natural resources. Today’s LCMR developed from a program initiated in 1963. Since that time, over $525 million has been appropriated to approximately 1,214 projects recommended by LCMR to protect and enhance Minnesota’s

For more information about new digester opportunities please contact Amanda Bilek, abilek@mnproject.org or 651-645-6159 x.5.