Continued assessment of corncobs as an alternative carbon source to enhance bioreactor performance for improved water quality

Aug 2021


Preliminary bioreactor work has shown that corncobs were a promising carbon source for nitrate removal from from agricultural water and showed improved NO3-N removal for all flows studied. However, better understanding of the corncob lifespan is needed to better estimate N removal costs for corncob reactors, relative to woodchip reactors.


The overall goal of this study is to compare nitrogen fate in corncob and woodchip bioreactors at the pilot scale.


Evaluation of the longer-term performance of bioreactors will be done with three different carbon sources 1)woodchip, 2) corncob-25 (25% corncob by length or volume) , and 3) corncob-5 (75% corncob by length or volume) . This will be done by monitoring total organic carbon, nitrate, ammonium, nitrous oxide, and methane (dissolved GHG) at the bioreactor inlet, within the bioreactor, and at the bioreactor outlet. Additionally, the research team will refine the existing technoeconomic analysis (TEA) to determine $/kg N removed using longer-term performance data and identify long-term supply sources of corncobs.