双膜曝气生物膜反应器除水中硝氮和高氯酸盐

Bioreduction of nitrate and perchlorate from aqueous solution using hydrogen/carbon dioxide membrane aeration biofilm reactor

构建了一种以CO_2为唯一碳源的膜曝气氢基质生物膜反应器(H_2-MBf R)对模拟地下水中2种主要的氧化型无机无污染物(NO_3^--N和ClO_4^-)进行生物还原去除.通过膜曝气方式使CO_2起到提供碳源和调节反硝化过程中pH值跃升的双重作用,克服了传统方法所带来的二次污染和运行成本增加的问题.通过调整H_2和CO_2压力能够实现对反应器出水pH值的较为稳定的控制,当CO_2压力分别为0.05MPa和0.08MPa 2个阶段时,在平均NO_3^--N和ClO_4^-进水浓度分别为20.73mg/L和10.57mg/L条件下,两阶段出水平均pH值分别为8.45和8.06,NO_3^--N和ClO_4^-去除率均大于95%;当第3阶段CO_2压力提升至0.12MPa时,平均出水pH值下降至6.93,此时NO_3^--N和ClO_4^-去除通量明显降低.而提供过量的CO_2会导致在偏酸性条件下甲烷化过程的产生,从而会导致其对H_2的负面消耗进而使目标污染物的还原速率下降.因此,合理控制CO_2压力使反应体系pH值维持在中性偏碱性条件下有利于NO_3^--N和ClO_4^-还原过程的高效进行.

A hydrogen-based membrane aeration biofilm reactor（H_2-MBf R） with carbon dioxide as the sole carbon source was applied for biodegradation of two typical oxidized pollutants（NO_3-N and ClO_4-） in simulative groundwater. In order to overcome the secondary pollution and high operation cost, CO_2 was supplied through the membrane aeration as carbon source and to control the pH during denitrification. The experimental results showed that the reactor effluent pH can be controlled relatively stable through the adjustment of H_2 and CO_2 pressure. In first two opreation stages, the CO_2 pressure was 0.05 MPa and 0.08 MPa, respectively, and the average influent concentrations of NO_3-N and ClO_4- were 20.73mg/L and 10.57mg/L, respectively, thus the average effluent pH was 8.45 and 8.06, respectively, and the removal rates of NO_3-N and ClO_4- were both higher than 95%; When the CO_2 pressure increased to 0.12 MPa in the third stage, the average effluent pH was dropped to 6.93, and the average surface loadings of NO_3-N and ClO_4- surface have decreased significantly. And methanation was caused owing to excess CO_2 under the condition of partial acid, which leads to the low reduction rates of goal pollutants. Therefore, reasonable control of the CO_2 pressure was conducive to high efficiencies of NO_3-N and ClO_4- reduction.