Slocum, Noah2013-04-232013-04-232013-04-19http://purl.umn.edu/148052Faculty adviser: Gary FeyereisenDenitrifying bioreactors are one possible solution to the problem of nitrate-nitrogen outflow from agricultural subsurface drainage to surface waters. This study was conducted to determine the effectiveness of a corn cob and wood chip mixture, comprised of an equal amount of each by weight, as a denitrifying bioreactor bed medium in comparison to both corn cobs and wood chips alone. The nitrate-nitrogen removal rates of these three media were tested by packing each into 15 cm by 50 cm PVC cylinders and pumping a solution with a 50 mg/L concentration of nitrate-nitrogen through them over a period of five months at a rate equivalent to a hydraulic resistance time of 12 hours. The entire apparatus was kept at 2˚ C as to imitate weather conditions common to Midwestern states in early spring. The average nitrate-nitrogen removal rates for the three media were: corn cob > mixture > wood chips.en-USCollege of Science and EngineeringBioproducts and Biosystems EngineeringUSDA-ARS Soil and Water Research UnitPresentation