Device and method for in-situ removal of nitrate in natural water

The invention provides a device and method for in-situ removal of nitrate in natural water. Mutual consumption between bottom sediment and nitrate nitrogen pollutants is finished through the oxidation reduction potential between the nitrate nitrogen (reducible) in water and bottom sediment organism (oxidable) so as to achieve an aim of accurately removing nitrate nitrogen. In the invention, the anode of a sediment microbial fuel cell is used for oxidizing the bottom sediment organism and releasing electrons, the microbial cathode adsorbs nitrate nitrogen in the polluted water through the pole surface and receives the electrons transferred from the microbial anode, and denitrification is performed on the microbial cathode to realize in-situ removal of nitrate nitrogen in water. In the invention, nitrogen in natural water is accurately removed, and secondary pollution is avoided; the investment cost of the method is relatively low, and after biofilm domestication, the whole process runs spontaneously and thus d