"Environment" research area

Bioaugmented Nitrogen Removal from Drainage System Water

Primary Investigator - Michael SadowskyPrimary InvestigatorMichael Sadowsky
Co-Investigators
Jeff Strock; Satoshi Ishii; Reda Abou-Shanab and Prince Mathai (Postdoctoral Scholars)
Industry Partners:
 Minnesota Department of Agriculture, Agricultural Utilization Research Institute, Minnesota Corn Growers Association
Award Type: Seed Grant - Postdoctoral Research Scholar

Problem: Roughly 60 million pounds of nitrogen flow through drainage systems in the Minnesota River basin each year. The nitrogen accumulates from agricultural runoff and enters the Mississippi River, resulting in environmental damage to local ecosystems as well as those downstream of the Mississippi, such as hypoxic zones in the Gulf of Mexico. Most drainage systems are unequipped to remove nitrogen before runoff enters groundwater systems. Recently developed bioreactors only extract about 30% of nitrogen from water and are not optimized for early spring cold temperatures - when runoff volume peaks. 

Solution: MnDRIVE researchers will begin by modifying existing, above-ground bioreactors in a field setting. The bioreactors will be inoculated with cold-adapted denitrifying bacteria (bioaugmentation) and observed at temperature settings between 5 and 15 degrees celsius. Ethanol will then be applied to microbial communities as a source of carbon, a process called biostimulation that will maximize the ability of microbes to remove nitrogen. Nitrogen removal capabilities will be recorded and genetic analysis will also be used to determine the abundance of microbes at the various settings used. Once the ideal conditions have been identified, current bioreactors at the Southwest Research and Outreach Center will be modified for in-field testing where similar measurements will be made to test the effectiveness of the above-ground biostimulation technology. 

Impact: Agriculture is one of Minnesota’s largest industries, but also contributes large amounts of nitrogen to runoff water. Applying biostimulation strategies to existing bioreactors will help increase nitrogen removal. Removing nitrogen from water before it enters rivers and streams will improve conditions of local ecosystems and reduce contribution to hypoxic zones downstream.