上流式Fe0-沸石固定床去除水中的硝酸盐氮

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Fe0-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(Fe0)/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。

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

Because of the high concentration of residual nitrate nitrogen after the biodegradation, the total nitrogen 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 activated carbon was 0.5, the removal efficiency of NO-3 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 powder in the reactor. The zeolite had high removal efficiency of ammonia nitrogen and good adjustment to the pH values of the effluent.