The North Carolina State University (NCSU) Animal and Poultry Waste Management Center heads the state's research and implementation efforts to address hog waste management problems. The Center is evaluating several technologies for implementation on private-sector hog farms throughout the state. All of these technologies would reduce methane emissions by using waste methane to generate energy instead of releasing it into the atmosphere. Anaerobic digestion processes generally refer to enclosed systems in which anaerobic bacteria metabolize farm waste and biogas is generated. The biogas produced by this process is approximately 65 percent methane, which can be used for energy production in the farm or converted to electricity and put onto the grid. In-ground, ambient, and thermophillic processes are all subsets of anaerobic digestion technology. In-ground refers to an earthen structure (as opposed to a steel tank, etc.). Ambient and thermophillic refer to the temperatures at which the digestion process takes place. Two pilot projects currently underway offer alternative uses for the wastes produced by conventional hog farming practices. One project uses ambient digestion to capture methane from an in-ground digester. The methane fuels a generator, which produces electricity for use on the farm. Waste heat from electric generation is used to produce hot water for the farm's production processes. A second project is using thermophillic anaerobic digestion technology to collect methane, which fuels a boiler to provide hot water used to maintain the required temperature for thermophillic digestion. North Carolina also has an operating ambient digester facility built in 1997 that converts the waste-derived methane from 4, 000 hogs into electricity and hot water for use on the farm. NCSU's research is expected to identify an environmentally superior technology for use on North Carolina's hog farms. The state defines environmentally superior technologies as those that are determined to be technically, operationally, and economically feasible while meeting five performance standards: (1) eliminating the discharge of animal wastes to surface waters and groundwater through direct discharge, seepage, or runoff; (2) substantially reducing atmospheric emission of ammonia; (3) substantially reducing any odor that is detectable beyond the boundaries of the parcel or tract of land on which the swine farm is located; (4) substantially reducing the release of disease-transmitting vectors and airborne pathogens; and (5) substantially reducing nutrient and heavy metal contamination of soil and ground water. By the end of 2003, technologies will be selected and applied on farms.