三维电极生物膜脱氮系统的电场响应性

Nitrogen reduction stimulated by a three-dimensional electrochemical-biofilm reactor and its correlation with electric field

研究三维电极生物膜反应器对加载电场的响应性,为寻求反应器有效合理的自动控制方式提供理论指导。为了充分利用三维电极体系阳极产氧为硝化菌提供好氧环境实现氨氮硝化,利用阴极产氢为反硝化菌提供缺/厌氧环境和电子供体实现反硝化脱氮,实验设计并稳定运行了三维电极生物膜脱氮反应器。通过考察不同电流密度条件下,系统溶解氧(DO)、pH、脱氮性能的变化,研究电流密度对三维电极生物膜反应器中微生物生长的微环境和微生物反硝化脱氮所需电子供体的影响,评价三维电极生物膜脱氮系统的电场响应性。结果表明,在电流密度为0.013 4mA/cm2时,NH4+-N转化率可达90%,NO3--N和TN去除率70%以上;三维电极生物膜脱氮系统的极限电流密度在0.020 1mA/cm2附近;极限电流密度范围内,电流密度引起系统DO、pH的变化均在系统承受范围内;电流密度的提高可提高阴极NO3--N反硝化效率,但对阳极NH4+-N的硝化无明显影响,极限电流密度范围内均无NO2--N积累。

To realize automatic control, it is important to study the response of reactor to electric field. A three-dimensional biofilm eletrode reactor is developed and steadily operated to remove nitrogen. In the reactor, oxygen is produced on the anode and hydrogen is produced on the cathode of the three-dimensional electrode by electrolysis water. Microorganism in the reactor utilize oxygen and hydrogen adequately to remove nitrogen by nitrification-denitrification. To evaluate the correlation of electric field with the reactor, DO, pH and nitrogen removal efficiency are studied. Results show that when a electric field of 0. 013 4 mA/cm2 is applied to the system, the removal rate of NH4＋-N, NO3-N and TN is 90%, 70% and 70%, respectively. To assure the reactor run efficiently, the maximum of the intensity of electric field applied to the reactor is 0. 0201 mA/cm2. Within 0. 0201 mA/cm2, the system is in stable running status, while DO and pH is altered resulting from the intensity of electric field. With enhancing the intensity of electric field, the removal rate of NO3--N can be improved, although, the removal rate of NH4＋ -N is not elevated markedly. There is no accumulation of NO2--N within 0. 0201 mA/cm2.