电极生物膜法反硝化工艺条件及过程

为获得具有良好反硝化性能的电极生物膜,以活性污泥为出发菌株,分别以连续和间歇培养方式在石墨电极上生长电极生物膜,研究碳氮比、电流强度、pH等工艺条件对电极生物膜反硝化过程的影响.结果表明:当碳氮比小于3.0时,体系的反硝化速率与碳氮比成正比;而在3.0以后,反硝化速率的增长开始趋于缓慢;电流强度为20mA时,硝酸盐去除效率达到最大值9.26mg/(L.h),继续加大电流,硝酸盐的去除率降低;当pH等于7时,硝酸盐氮的去除负荷最大,为7.89mg/(g.h),而pH小于或大于7时,生物膜的反硝化性能均有所降低.对单纯电极法、单纯生物膜法和电极生物膜法进行比较研究,证明电极生物膜法对硝酸盐的去除是电与生物膜共同作用的结果.

Technological conditions and process analysis on denitrification of biofilm-electrode system

In order to acquire biofilm-electrode with good denitrification ability,biofilm-electrodes were obtained on graphite plates by continuous and batch culture methods with activated sludge,respectively. The influences of C/N ratio,current intensity and pH value on the denitrification process were evaluated. The results indicated that the denitrification rate was in direct proportion to the C/N ratio when the ratio of C/N was less than 3.0,while the increasing rate of denitrification was slowed down when the ratio of C/N was above 3.0. A maximum value of 9.26 mg/(L·h)for nitrate removal efficiency was gotten when a current intensity of 20 mA was applied. With larger amounts of current density,the nitrate removal efficiency was decreased. A nitrate removal loading of 7.89 mg/(g·h) was obtained when pH was at 7,but the denitrification ability of biofilm-electrodes was decreased with the pH value above or below 7. A comparison of denitrification with methods of electrolysis,biofilm and biofilm-electrode was carried out and a cooperation evidence of electrode process and biofilm was proved.