| The experiments using low C/N ratio wastewater containing nitrate were carried out to investigate the denitrification performances of a self-made three-dimensional electrode-biofilm reactor. A synthetic secondary effluent containing nitrate and organic materials and high NO3--N concentration sewage were studied in this thesis. The results obtained in this study are described as follow.The advanced denitrification and organic materials removal performances were studied by the self-made three-dimensional electrode-biofilm reactor using a synthetic secondary effluent. An inhibition effect was observed. The optimum current was 20mA for the synthetic polluted water containing 40mg/L NO3--N and 100mg/L COD, and the peak current efficiency was up to 1003%. It was found that the denitrification rate was irrelevant to the concentration of NO3--N but influenced by the current and organic carbon source. The nitrate removal efficiency of the three-dimensional electrode-biofilm reactor was 4.5 times higher than that of the biofilm reacor. So, in some way, it could solve the problem of lack of carbon source. When the nitrate removal efficiency was about 90%, the reactor only consumed 0.05KW·h power for the sewage containing 30mg/L NO3--N and 100mg/L COD. Accordingly, the reactor was operated well under low energy- consumption.For high NO3--N concentration sewage, the bipolar three-dimensional electrode was reformed to a monopolar three-dimensional electrode, on which the nitrate removal efficiency was about 85%, about 2.4 times higher than that on the bipolar three- dimensional electrode-biofilm reactor.In conclusion, the microorganism in the three-dimensional electrode-biofilm reactor could denitrify by simultaneously utilizing the organic materials and hydrogen gas from the electrolysis of water. Meanwhile, COD could be removed effectively. The reactor was operated well under low energy-consumption. It would be a promising technique for low C/N ratio wastewater treatment.
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