Woodchip bioreactors are subsurface trenches filled with a carbon source, mainly wood chips, through which water is allowed to flow just before leaving a field to enter a surface water body. The carbon source in the trench serves as a substrate for bacteria that break down the nitrate through denitrification. Woodchip bioreactor costs include the control structures, woodchips, design, construction, seeding, additional tile, management and maintenance.
Photo credit: "Christianson and Helmers, 2011"
The Many Advantages of Woodchip Bioreactors:
- They use proven technology
- They require no modification of current practices
- No land needs to be taken out of production
- There is no decrease in drainage effectiveness
- They require little or no maintenance
- They last for roughly 10 years
See a woodchip bioreactor under construction and learn more about their benefits in the video below, produced by The Illinois Water Resources Center: