Luo Qishi, Wang Hui, Zhang Xihui, Fan Xiangyu, Qian Yi
Department of Environmental Science and Engineering, Tsinghua University, Beijing 100084, PR China.
Chemosphere. 2006 Jun;64(3):415-22. doi: 10.1016/j.chemosphere.2005.11.064. Epub 2006 Jan 10.
In situ bioremediation is a safe and cost-effective technology for the cleanup of contaminated sites, but its remediation rate is usually very slow. This study attempted to accelerate the process of bioremediation by employing non-uniform electrokinetic transport processes to mix organic pollutants and degrading bacteria in soils under in situ conditions (namely, in situ bioelectrokinetic remediation) by use of an electrode matrix and a rotational operation mode. A bench-scale non-uniform electrokinetic system with periodic polarity-reversal was developed for this purpose, and tested by using a sandy loam spiked with phenol as a model organic pollutant. The results demonstrated that non-uniform electrokinetic processes could enhance the in situ biodegradation of phenol in the soil, the efficiency of which depended upon the operational mode of the electric field. Compared with the unidirectional operation and the bidirectional operation, the rotational operation could effectively stimulate the biodegradation of phenol in the soil if adopting appropriate time intervals of polarity-reversal and electrode matrixes. A reversal interval of 3.0 h and a square-shaped electrode matrix with four electrode couples appeared appropriate for the in situ biodegradation of phenol, at which a maximum phenol removal of 58% was achieved in 10d and the bioremediation rate was increased about five times as compared to that with no electric field applied. The results also showed that adopting a small polarity-reversal interval and an appropriate electrode array could produce a high and uniform removal of phenol from the soil. It is believed that in situ bioelectrokinetic remediation holds the potential for field application.
原位生物修复是一种用于清理污染场地的安全且具有成本效益的技术，但其修复速率通常非常缓慢。本研究试图通过采用非均匀电动传输过程，利用电极矩阵和旋转操作模式，在原位条件下（即原位生物电动力学修复）将土壤中的有机污染物和降解细菌混合，以加速生物修复过程。为此开发了一种具有周期性极性反转的实验室规模非均匀电动系统，并以添加苯酚的砂壤土作为典型有机污染物进行测试。结果表明，非均匀电动过程可以增强土壤中苯酚的原位生物降解，其效率取决于电场的操作模式。与单向操作和双向操作相比，如果采用适当的极性反转时间间隔和电极矩阵，旋转操作可以有效促进土壤中苯酚的生物降解。3.0小时的反转间隔和具有四对电极的方形电极矩阵似乎适合苯酚的原位生物降解，在此条件下，10天内苯酚的最大去除率达到58%，与不施加电场相比，生物修复速率提高了约五倍。结果还表明，采用较小的极性反转间隔和合适的电极阵列可以使土壤中的苯酚实现高效且均匀的去除。据信，原位生物电动力学修复具有现场应用的潜力。
