稠油污染土壤微生物修复试验研究

Experimental Study on Bioremediation of Heavy Oil Contaminated Soil

辽河油田集输站落地稠油污染1号土壤为松散的硬固体,含油7.4%、含水率17.8%、密度2.64 g/cm3、pH值7.8;稠油污染2号土壤为黏结的软固体,含油21.5%、含水率35.6%、密度2.23 g/cm3、pH值7.8。污染1号土壤的稠油含饱和烃29.11%、芳香烃22.54%、胶质30.26%、沥青质18.08%;污染2号土壤的稠油含饱和烃25.19%、芳香烃26.23%、胶质32.49%、沥青质16.09%。从稠油污染土壤中富集、分离、筛选出1～5号菌株。以稠油为唯一碳源,1～5号菌株对原油的降解率分别为20.0%、6.1%、22.5%、12.7%、34.7%。选择降解率较高的5号菌和对环境适应性良好的1号菌作为优势菌。1号菌的最佳N、P源分别为(NH4)2SO4和K2HPO4,降解率分别为28.13%和15.16%;5号菌的最佳N、P源分别为KNO3和KH2PO4,降解率分别为49.12%和50.04%。0.15%H2O2具有良好的氧化降解效果和促进作用,但单独使用的降解率为25%(60 d)。添加表面活性剂后,含油土壤60 d内的降解率大幅提高,吐温-80、吐温-40、鼠李糖脂最高降解率分别达73%、70%、84%。选择0.1%吐温-80和0.1%鼠李糖脂复合表面活性剂作为油污土壤微生物降解的渗透剂。通过小型扩大修复实验,经过80 d的修复,1号、2号稠油污染土壤的降解率分别为66.7%和73.5%,降解效果良好。

The loose and hard soil was named No. 1 which formed by ground crude oil from Liaohe oilfield gathering station, with 7.4% oil and 17.8% water content, 2.64 g/cm3 density and 7.8 pH value. Heavy oil contaminated soft and bonding soil was named No. 2, with 21.5% oil and 35.6% water content, 2.23 g/cm3 density and 7.8 pH value. Heavy oil contaminated No. 1 soil contained 29.11% saturated hydrocarbon, 22.54% aromatic hydrocarbon, 30.26% colloid and 18.08% asphaltene. Heavy oil contaminated No. 2 soil contained 25.19% saturated hydrocarbon, 26.23% aromatic hydrocarbon, 32.49% colloid and 16.09% asphaltene. 1--5 strains was selected by enrichment and separation from heavy oil contaminated soil. Taking heavy oil as sole carbon source, the degradation rate of 1--5 strains to crude oil was 20.0%, 6.1%, 22.5%, 12.7% and 34.7%, respectively. No. 5 strain with higher degradation rate and No. 1 strain with good adaptability to environment were isolated as predominant bacteria. The optimum N and P source of No. 1 bacteria was （NH4）2SO4 and K2HPO4, the corresponding degradation rate was 28.13% and 15.16%. And that of No. 5 bacteria was KNO3 and KH2PO4, the correspond!ng degradation rate was 49.12% and 50.04%. 0.15% H2O2 had a good effect of oxidative degradation and promoted a role, however, the degradation rate used H2O2 alone was 25% （60 d）. Within 60 days after adding surfactants, oily soil degradation rate greatly increased. The highest degradation rate of TW-80, TW-40 and rhamnolipid was 73%, 70% and 84% respectively. So 0.1% TW-80 and 0.1% rhamolipid composite surfactant was selected as penetrating agent for oil soil microbial degradation. Through the small scale test, the degradation rate of No. 1 and No. 2 heavy oil contaminated soil achieved 66.7% and 73.5% respectively 80 days later which indicated the degradation effect was good.