高羊茅对电动-微生物修复石油污染土壤的影响

通过在电动-微生物修复土壤系统内种植植物(高羊茅),研究植物对污染土壤修复过程中电流变化、土壤微生物数量、活性及污染物去除的影响。实验设置4类处理:(1)电动-微生物修复(EK+BIO);(2)电动-植物修复(EK+P);(3)植物-微生物修复(P+BIO);(4)电动-植物-微生物修复(EK+P+BIO),修复系统运行60 d。结果表明:高羊茅对电动修复系统内电流的衰减具有明显的延缓作用;与未施加电场的处理组相比,施加电场的处理组高羊茅生物量显著提高(P0.05);实验进行15 d时,EK+P+BIO组的微生物数量以及脱氢酶活性较初始值分别增加了22.23%和23.36%;30 d和60 d时,各处理组的微生物数量以及脱氢酶活性均有所降低,但EK+P+BIO组测定结果在各处理中始终保持最高水平;EK+P+BIO处理对土壤中总石油烃的去除率达48.21%,显著高于其他处理(P0.05)。因此,在污染土壤电动-微生物修复系统中,种植高羊茅可有效延缓电流的衰减趋势,为微生物提供有利的根区环境,改善土壤微生物活性,从而提高电动-微生物修复系统中总石油烃的去除率。

Effect of tall fescue on electro-bioremediation of petroleum-contaminated soil

In this study, the effects of plants on the changes in electric current, the quantity and activity of soil microorganisms, and the removal of pollutants through the process of remediation of contaminated soil were investigated by planting(tall fescue)in the electro-bioremediation system. Four treatments were set up in the experiment:(1)Electro-bioremediation(EK+BIO),(2)Electric-phytoremediation (EK+P), (3) Phyto-bioremediation(P+BIO), (4) Phyto-electro-bioremediation(EK+P+BIO). The experiments were performed for 60 days. The results show that the tall fescue has a significant retarding effect on the reduction of electric current in soil. Compared with the test without the electric field, the biomass of tall fescue was higher in the test with the electric field. After 15 days, the number of microorganisms and the amount of dehydrogenase activity in the EK+P+BIO group increased by 22.23% and 23.36% respectively, which were significantly higher than those of other tests. At 30 d and 60 d, the number of microorganisms and the amount of dehydrogenase activity in each treatment were reduced, but the values of the EK+P+BIO group were still the highest in all the treatments. In addition, 48.21% of total petroleum hydrocarbon was removed in the EK+P+BIO group, which was significantly higher than other treatments. Therefore, the planting of tall fescue can effectively delay the trend of electric current attenuation, provide a favorable root zone environment for microorganisms, improve soil microbial activity, and improve the removal rate of total petroleum hydrocarbon in the electro-bioremediation system.