从活性污泥中筛选出一株高效高氯酸盐降解菌,对其进行常规的生理生化实验,并结合16S rDNA序列分析,比对结果表明,该菌株与变形菌纲(Thauera Phenylacetica)的相似性达99%。此菌株和纳米铁以海藻酸钙为载体,制备了纳米铁/微生物小球(NMBs),并研究其微观结构和去除高氯酸盐的性能。同时也考察了不同温度和pH等环境条件下,该体系及其游离体系去除高氯酸盐效果的对比。结果表明,所制备的小球直径为3~5 mm,表面布满孔道,利于物质的进入。小球去除高氯酸盐的过程主要是吸附、化学还原和生物降解三阶段共同作用的结果,其中后两阶段,均符合一级动力学规律。同时还发现,温度适中(30℃左右),中性pH(约7.8)环境下小球体系去除高氯酸盐效果最佳,且该体系对温度和pH适应能力较强,有利于实际污染的原位修复。
A strain with capability of reducing perchlorate was isolated from activated sludge. In addition to general morphological and biochemical characteristics, the strain was identified by 16S rDNA sequence and systematic analysis. The results show that its 16S rDNA sequence of strain has similarity of 99% with the Thauera Phenylacetica strain. The beads of immobilized NZVI combined with microbes were prepared with calcium alginate as encapsulated carrier. Scanning electron microscopy was used to study the bead microstructure, and its perchlorate degradation performance was further studied. The batch experiments were carried out to examine the perchlorate removal rate under different temperatures and pHs. Results show that the beads with diameter of 3-5 mm have many holes which allow the materials to enter availably, and the perchlorate reduction process is based on the adsorption and chemical reduction combined with biodegradation. And, the latter two processes are in accord with the process of one-order kinetics. In addition, it shows that the better removal efficiency could occur under moderate temperature and neutral pH value. Based on its good adaption of the temperature and pH, the beads with immobilized nanoscale Fe^0 and microbes are favorable for in-situ remediation.