双膜曝气生物膜反应器除水中硝氮和高氯酸盐

构建了一种以CO₂为唯一碳源的膜曝气氢基质生物膜反应器（H₂-MBfR）对模拟地下水中2种主要的氧化型无机无污染物（NO₃^--N和ClO₄^-）进行生物还原去除.通过膜曝气方式使CO₂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H₂和CO₂压力能够实现对反应器出水pH值的较为稳定的控制，当CO₂压力分别为0.05MPa和0.08MPa 2个阶段时，在平均NO₃^--N和ClO₄^-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，NO₃^--N和ClO₄^-去除率均大于95%；当第3阶段CO₂压力提升至0.12MPa时，平均出水pH值下降至6.93，此时NO₃^--N和ClO₄^-去除通量明显降低.而提供过量的CO₂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H₂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CO₂压力使反应体系pH值维持在中性偏碱性条件下有利于NO₃^--N和ClO₄^-还原过程的高效进行.

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

A hydrogen-based membrane aeration biofilm reactor (H₂-MBfR) with carbon dioxide as the sole carbon source was applied for biodegradation of two typical oxidized pollutants (NO₃^--N and ClO₄^-) in simulative groundwater. In order to overcome the secondary pollution and high operation cost, CO₂ 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 H₂ and CO₂ pressure. In first two opreation stages, the CO₂ pressure was 0.05 MPa and 0.08 MPa, respectively, and the average influent concentrations of NO₃^--N and ClO₄^- 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 NO₃^--N and ClO₄^- were both higher than 95%; When the CO₂ 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 NO₃^--N and ClO₄^- surface have decreased significantly. And methanation was caused owing to excess CO₂ under the condition of partial acid, which leads to the low reduction rates of goal pollutants. Therefore, reasonable control of the CO₂ pressure was conducive to high efficiencies of NO₃^--N and ClO₄^- reduction.