生物强化处理石油污染土壤理化性质和微生物学特性的纵向分布特征

采用原位强化生物修复技术对某区块石油污染土壤进行为期16个月的生物修复,考察了处置后污染土壤理化性质、微生物学特性以及石油烃组成的纵向分布特征。实验结果表明,经过修复后各土层的石油烃去除率是表层土IN-3(50.42%)中层土IN-2(23.54%)底层土IN-1(10.51%);IN-1处于缺氧环境,存在硫酸盐还原和反硝化作用,使得土壤pH值从7.86±0.03降低至7.27±0.03,土壤总氮从2.53±0.13 g/kg降低至0.77±0.04 g/kg;厌氧菌的种群数量是IN-1(10.43±0.71×104CFU/g)IN-3(6.74±0.39×104CFU/g)IN-2(5.15±0.42×104CFU/g),放线菌数量与石油烃含量显著负相关(r=-0.989,p=0.0110.05);IN-3对饱和份和芳香份的降解率最高,分别达到了70.27%和54.52%,远高于IN-2和IN-1;模拟蒸馏结果表明,IN-3正构烷烃得到了很大程度的去除,缺氧的IN-1对正构烷烃去除得较少;厌氧菌数量与胶质和沥青质去除率之间成正相关关系,对于污染源较为分散的污染区域,采用原位生物强化修复时可以考虑引入厌氧修复。

Vertical distribution of the physicochemical and biochemical properties of oil contaminated soil by bioaugmentation

The in-situ bioaugmentation strategy was used for bioremediation a oil contaminated soil for 16 months, the vertical distribution of the physicochemical, biochemical properties and hydrocarbon composition were studied. The test results showed that the order of oil removal rate was surface soil(IN-3)(50.42%)> middle soil(IN-2)(23.54%)>subsurface soil(IN-1)(10.51%). As sulfate reduction and nitrate reduction took place in subsurface soil, the pH reduced from 7.86±0.03 to 7.27±0.03, and the TN reduced from 2.53±0.13 g/kg to 0.77±0.04 g/kg. The order of anaerobic bacterial count was IN-1(10.43±0.71×10⁴ CFU/g)>IN-3(6.74±0.39×10⁴ CFU/g)>IN-2(5.15±0.42×10⁴ CFU/g),and there had a negative and significant impact on the level of trust(r=-0.989, p=0.011<0.05) between actinomycetes count and TPH. The saturate and aromatic removal rates of surface soil were highest compare to the IN-2 and IN-1 soil, reached 70.27% and 54.52%, respectively. The GC results showed that the n-alkanes of the surface soil was degraded extremely, and the n alkanes of the subsurface soil was degraded very small. The removal rate of resin and asphaltene was related to the anaerobic bacterial count. The anaerobic bioremediation strategy should be considered when the in-situ remediation was applied in the oil contaminated area which polluted dispersively.