Biofilm samples at different magnetic field intensities and CO2 supply conditions
The samples were taken from four bioreactors based on iron-carbon carriers. The experiment was conducted at a concentration of ~27 mg/L total nitrogen. The samples were collected from biofilm on iron-carbon carriers under different magnetic field intensities and CO2 supply conditions during the stable operation stage (day 56). Biofilm samples were obtained by mixing the biofilms on the upper, middle, and bottom of the reactor.