Determine if a novel design for denitrifying bioreactors will make bioreactors a feasible practice for nitrate and phosphate loss reduction in Northwestern Minnesota on sandy ridges. Bioreactors are listed as a primary tool for nitrate reduction in the Minnesota Nutrient Reduction Strategy, but these practices are not adapted for the conditions and drainage systems found in Northern Minnesota. Our primary focus will be a cost-benefit analysis of reducing nutrient loss to groundwater and surface water from a new bioreactor system. Northwestern Minnesota’s cold climate is a challenge for the efficiency of bioreactor systems, but lift stations offer an opportunity to improve their efficiency. Lift stations pumping mechanism would allow the bioreactor to operate consistently under a pumped flow rates instead of the highly variable flow rates of gravity-outlet systems. This would allow the bioreactor to operate nearer to a steady-state mode. This could improve the denitrifiers ability to remove N and improve its efficiency during the growing season.
In addition, we propose to monitor P losses from the bioreactor system immediately after installation, and over time. While bioreactors are known for their ability to reduce N, sufficient data to understand their effect on P is not yet available (Addy et al., 2016). This knowledge gap is critical for Northwest Minnesota because waters flow northward into Canada’s Lake Winnipeg, which has been suffering from water quality impairment due to excessive P loading. We aim to address this gap in understanding by adding P monitoring in the bioreactor system.