上流式Fe^0-沸石固定床去除水中的硝酸盐氮

Removal of nitrate nitrogen from wastewater in upstream zero-valent iron-zeolite fixed bed reactor

针对目前废水经生化处理后,残余NO_3^-浓度较高导致总氮不达标的问题,采用上流式Fe^0-沸石固定床对其进行处理,探究了纯铁粉+沸石、铁粉/石英砂+沸石和铁粉/活性炭+沸石3种填料对硝酸盐氮废水的处理效果。实验结果表明,当进水NO_3^-浓度为50 mg·L^(-1),pH=6,V(Fe^0)/V(活性炭)=0.5时,NO_3^-去除率可达75.99%,反应符合准一级反应动力学模型,反应速率常数可达0.084 min^(-1),且反应产物中氨氮的比例较低。活性炭或石英砂的加入可以减缓反应柱内铁粉的板结。反应柱内的沸石对氨氮具有良好的吸附效果,且对出水的pH具有一定的调节作用。

Because of the high concentration of residual nitrate nitrogen after the biodegradation, the total nitro- gen of wastewater would exceed standards. The removal efficiency of nitrate nitrogen of Fe0-zeolite, Fe0/quartz sand-zeolite and Fe0/activated carbon-zeolite from wastewater in an upstream fixed bed reactor was studied. When the initial nitrate concentration was 50 mg· L- 1, the initial pH was 6 and the volume ratio of Fe0 and acti- vated carbon was 0.5, the removal efficiency of NO3- could account for 75.99% , and the proportion of ammonia in the reduction products was low. The process met pseudo first order reaction, and the reaction constant was 0. 084 min-1 The addition of quartz sand or activated carbon could effectively reduce the hardening of iron pow- der in the reactor. The zeolite had high removal efficiency of ammonia nitrogen and good adjustment to the pH values of the effluent.