Abstract:

The denitrification efficiencies of two continuous flow mixed-culture denitrification reactors with Fe⁰ alone and carbon fiber reinforced Fe⁰ were compared by treating the synthetic wastewater containing NO₃ ^--N. The results showed that the average removal efficiencies of total nitrogen(TN) and NO₃ ^--N were as high as 89.04% and 97.13% for the experimental group R1 with carbon fiber and Fe⁰ injection at COD/NO₃ ^--N of 2.9-3.1 and hydraulic retention time(HRT) of 24 h, which were significantly higher than the control group R0 with Fe⁰ injection alone. The extracellular polymeric substances(EPS) and electron transfer activity(ETSA) variation patterns indicated that the input of carbon fiber further promoted the synthesis of EPS and enhanced the utilization of electrons by microorganisms. Scanning electron microscopy-energy dispersive spectrometry(SEM-EDS) and X-ray diffractometer(XRD) analyses revealed that there was obvious microbial corrosion on the surface of Fe⁰ in R1 reactor, and FeO(OH) and bioorganic-Fe complexes were the main corrosion products. Microbiological analysis showed that the increase of organic carbon source and the injection of carbon fiber effectively increased the abundance of iron autotrophic denitrifying bacteria genus and promoted the enrichment of denitrifying functional genes.

Key words: NO₃ ^--N wastewater, Fe⁰, carbon fiber, mixotrophic denitrification, COD/NO₃ ^--N, microbial community structure

摘要：

以含NO₃ ^--N合成废水为处理对象，对比了单独投加Fe⁰与碳纤维强化Fe⁰混养反硝化连续流反应器反硝化脱氮的效能。结果表明，在COD/NO₃ ^--N为2.9~3.1、水力停留时间（HRT）为24 h时，投加碳纤维强化Fe⁰的实验组R1对TN和NO₃ ^--N平均去除率分别高达89.04%和97.13%，显著高于单独投加Fe⁰的对照组R0。胞外聚合物（EPS）及电子传递活性（ETSA）变化规律表明，碳纤维的投入可进一步促进EPS生成，且强化了微生物对电子的利用率。扫描电镜-能量色散光谱仪（SEM-EDS）和X射线衍射仪（XRD）分析结果发现R1中Fe⁰表面有明显的微生物腐蚀现象，FeO（OH）和含铁有机复合物是主要的腐蚀产物。微生物学分析表明，有机碳源投加量的提高及碳纤维的投加有效提高铁自养反硝化菌属丰度，促进反硝化功能基因的富集。

关键词: NO₃ ^--N废水, Fe⁰, 碳纤维, 混养反硝化, COD/NO₃ ^--N, 微生物群落

CLC Number: 

• X703.1