混合烃污染土壤微生物-电动修复中的互补性研究

Complementarity of bio-electrokinetics in the remediation of soil contaminated with multiple hydrocarbons

为探讨微生物降解和电化学氧化分别在去除不同烃类时的具体作用,分别以正十六烷、环十二烷和芘作为直链烷烃、环烷烃和多环芳烃的代表性污染物,以具有不同烃类降解能力的菌株所构建的菌群为降解的微生物,以二维对称电场为修复平台,以电动修复、微生物修复和微生物-电动联合修复为研究基础,分析了不同修复方式中不同烃类污染物降解的时空特征和微生物数量、活性变化。结果表明,微生物-电动联合修复效率显著高于单一修复,在联合修复过程中,土壤脱氢酶活性和细菌数量明显升高,有利于污染物的降解。微生物降解作用和电化学氧化作用在不同烃类污染物的去除中均体现出了互补性,其中正十六烷和芘的去除较多地依赖于微生物的降解作用,而环十二烷的去除则较多地依赖于电化学氧化作用。另外,微生物降解作用在场强较弱的位点贡献较大,而电化学氧化作用在场强较强的电极附近贡献较大。

To evaluate the specific effects of biological degradation and electrochemical oxidation in the removal of different hydrocarbons, the temporal and spatial degradation characteristics of different hydrocarbons and changes of microbial numbers and activity were analyzed. The hydrocarbons, n-hexadecane, cyclododecane, and pyrene, were selected as representative pollutants of alkanes, cyclanes, and polycyclic aromatic hydrocarbons, respectively. Based on the following remediation techniques：electrokinetics（EK）, bioremediation（BIO）, and bio-electrokinetics（BIO-EK）, a remediation platform of a 2-dimensional（2-D）symmetrical electric field was applied, which was inoculated with complex bacterial strains able to degrade various petroleum hydrocarbons. The results demonstrated a significant enhancement in remediation efficiency of BIO-EK than that of BIO or EK alone. An obvious increase in microbial activity and numbers in soil was detected in the BIOEK test, which enhanced degradation efficiency in different hydrocarbons. It showed a complementarity between biological degradation and electrochemical oxidation in the removal of different hydrocarbons, and n-hexadecane and pyrene decreased more with biological degradation, whereas the cyclododecane decreased more with electrochemical oxidation. In addition, biological degradation was more effective at positions with weaker electric intensity, whereas electrochemical oxidation was more effective at positions with stronger electric intensity.