Forest to Farm
The “Forest-to-Farm” (FTF) network aims to ease bioreactor adoption by using diverse, locally available carbon media. The ISU team collaborates with Polk County Watershed Management Authorities and other conservation partners to establish on-farm trials by designing and installing 27 denitrifying bioreactors filled with conventional (4 bioreactors) and alternative carbon media (23 bioreactors). Alternate carbon materials include various wood species and chip/shred sizes and corncobs. ISU will evaluate the performance of all 27 bioreactors by monitoring the nitrate and total organic carbon concentrations at the bioreactor inlet and outlet. A tracer study will also be conducted at each bioreactor to evaluate the in-situ hydraulic properties.
Pilot-Scale Bioreactors
Nine pilot-scale bioreactors were installed at the Agricultural Engineering Research Farm near Ames, Iowa in 2014. These experimental bioreactors can be used to test nutrient removal from bioreactors designed with varying hydraulic retention time or receiving varying influent nutrient concentrations. In 2018, six of the bioreactors were partially excavated to replace a portion of the original woodchips in those bioreactors with corncobs.
Dual-Chamber Bioreactor
A dual-chamber bioreactor, with two 120′ x 34′ parallel chambers, was installed near Big Creek in 2018. The unique research design includes two identically designed chambers, individual inlet and outlet controls for each chamber, nine sampling wells randomly installed along the length and width of each chamber to evaluate nutrient dynamics throughout the bioreactor, and a pumping system to pull water from Big Creek to supplement flow during the drainage season.
