Tan Youming, Wang Meng, Luo Qifang
School of Public Health, Shanghai Second Medical University, 200025 Shanghai, China.
Wei Sheng Yan Jiu. 2004 Sep;33(5):527-30.
To optimize the efficiency of coated electrode denitrifying reactor.
Synthetic groundwater was treated by coated electrode denitrifying reactor submitted to different operational parameters, such as electric current intensity (CI), oxidation reduction potential (ORP), hydraulic retention time (HRT) and temperature.
Denitrification efficiencies of the reactor was found to be related with the applied electric current. The denitrification efficiency was 57.3% with a HRT of 12 hours and the optimum applied electric current intensity was 15 mA. Nitrate removal rate of the reactor was calculated to be 34.4 g NO3(-)-N/m3 x d. Denitrification efficiencies were also found to be related to HRT. The average denitrification velocity was 0.183 mg NO3(-)-N/h within 12 hours. The denitrification rates increased when the temperature of synthetic water raised from 5-35 degrees C. After the electrodes had been connected to the power supply for 1 hour, the concentration of dissolved oxygen (DO) and ORP decreased sharply to 1.08 mg/L and -40 mV, respectively.
An adaptable reduction environment could be set up in the reactor for autotrophic denitrification shortly after the bio-electrochemical reaction began. The optimum electrode potential and current density were 2.5 V and 0.083 mA/cm2 . As the bio-electrochemical reaction went on, the pH volume decreased sharply, and nitrite accumulation was found corresponsively, which leads to the inhibition of denitrification. HRT should be controlled within 12 hours. Anode oxidation reaction could offer inorganic carbon sources for autotrophic denitrifying bacteria, but might lead to pH increase, should be paid attention in the practical operation.
优化涂层电极反硝化反应器的效率。
采用涂层电极反硝化反应器处理合成地下水，考察不同运行参数，如电流强度（CI）、氧化还原电位（ORP）、水力停留时间（HRT）和温度等对处理效果的影响。
发现反应器的反硝化效率与施加的电流有关。水力停留时间为12小时时，反硝化效率为57.3%，最佳施加电流强度为15 mA。计算得出反应器的硝酸盐去除率为34.4 g NO3(-)-N/m3·d。反硝化效率也与水力停留时间有关。在12小时内，平均反硝化速度为0.183 mg NO3(-)-N/h。当合成水温度从5℃升高到35℃时，反硝化速率增加。电极接通电源1小时后，溶解氧（DO）浓度和氧化还原电位分别急剧降至1.08 mg/L和 -40 mV。
生物电化学反应开始后不久，反应器内可建立适合自养反硝化的还原环境。最佳电极电位和电流密度分别为2.5 V和0.083 mA/cm2。随着生物电化学反应的进行，pH值急剧下降，相应地发现有亚硝酸盐积累，从而导致反硝化作用受到抑制。水力停留时间应控制在12小时以内。阳极氧化反应可为自养反硝化细菌提供无机碳源，但可能导致pH值升高，在实际运行中应予以关注。
