Water Resources Research Act Program

Details for Project ID 2009MD193B

Low-cost Anaerobic Digesters for Dairy Manure Treatment and Renewable Energy Production

Institute: Maryland
Year Established: 2009 Start Date: 2009-05-01 End Date: 2012-05-31
Total Federal Funds: $31,933 Total Non-Federal Funds: $64,646

Principal Investigators: Stephanie Lansing

Project Summary: Improper treatment of dairy manure results in contamination of waterways, noxious odors, and the release of methane, which is a greenhouse gas with 21 times the global warming potential of carbon dioxide. When properly harnessed in an anaerobic digestion, animal wastes can be used to create renewable energy (methane ‘biogas’) and an improved fertilizer while reducing water pollution, greenhouse gas emissions, and odor. Digesters can reduce water and odor pollution from dairy facilities by eliminating lagoon management systems, thereby, reducing emissions of methane, carbon dioxide, hydrogen sulfide, and ammonia, increasing nitrogen and phosphorus soil infiltration after field application, and reducing surface runoff of organic pollutants and nutrients. Averaging $1 million, U.S. digesters are capital and management-intensive systems. The U.S. EPA recommends digesters only if a farm exceeds 500 cows, but in the Chesapeake Bay Watershed, only 1.2 % of dairy farms have herds that large. Low-cost anaerobic digestion is a proven technology in developing countries, with over 10 million low-cost digesters in India, China, and Latin America. The transfer of this technology to temperature zones in the U.S. has not been explored previously. The proposed research will develop new low-cost designs that will make digesters available to the overwhelming majority of farmers in the Chesapeake Bay watershed. Eight field-scale low-cost digesters, using two separate operating designs, will be constructed at the Clarksville Maryland Research and Education Center (CMREC) dairy farm and monitored for three years in order to determine the optimal design for low-cost digesters in a temperate climate and statistically analyze variability between digester designs and over time. Four existing wetland treatment cells will be used for further treatment of the effluent to determine if nutrient reductions to background levels are possible. The study results will be utilized in a dynamic model to determine how specific operating conditions affect digester performance and allow for comparisons between small-scale and industrial-scale digesters. The new knowledge created from this research will improve scientific understanding of digesters and provide medium to small-scale farmers with a digestion system that produces energy to meet farm needs while providing fertilizer for their crops, and reducing nutrient translocation, pathogens, environmental degradation, and greenhouse gas emissions.