Title: NERF bioreactor
Location: Northeast Research and Demonstration Farm
Time Period: 2009-present
Research Team: Matt Helmers, Carl Pederson, and Laura Christianson
Project Description: Denitrification bioreactors for removal of nitrate in tile drainage are new water quality technology that has rapidly gained interest in Iowa. A bioreactor is composed of an excavated trench filled with woodchips that are colonized by denitrifying bacteria. As drainage waters containing nitrate flow by these “good” bacteria, they convert the nitrate in the water to nitrogen gas. A critical component in evaluating the performance of these treatment systems is the documentation not only of nitrate concentrations in the drainage water, but also the flow rate and volume of the water treated in the bioreactor.
A denitrification bioreactor was installed at the Northeast Research and Demonstration Farm in April 2009 with flow monitoring equipment installed later that fall. A unique feature of this bioreactor was that it was constructed with a trapezoidal cross-section, the first to do so in the state. The bioreactor’s dimensions were120ft long × 3ft deep ×15 ft (top width) to 8 ft (bottom width). Hardwood chips from a local supplier were used as fill material. Water depths were monitored with pressure transducers in the inlet and outlet control structures and were converted to flow rates using rectangular weir flow equations.
Publications: Christianson, L., A. Bhandari, M.J. Helmers, K. Kult, T. Sutphin, and R. Wolf. 2012. Performance evaluation of four field-scale agricultural drainage denitrification bioreactors in Iowa. Trans. ASABE 55(6): 2163-2174.
Funders: This bioreactor was installed with support from the Coldwater-Palmer Watershed group. Funding for monitoring has been provided by the Leopold Center for Sustainable Agriculture and USDA-AFRI.
Disclaimer: This is an active research site, please contact the research team prior to planning any site visits.