油污土壤修复微生物的筛选及其影响因素

目的]探讨微生物原位修复的主要影响因素及水平(正交设计)之间的关系,为石油污染场地生物修复工程的参数设计提供一定理论依据。方法]选取5因素4水平的正交设计,考察污染强度、营养物、氧化剂、表活剂、接菌量等因素对土壤修复效果的影响。结果]以原油为唯一碳源经过初步筛选,获得16株石油烃降解优势菌,经过菌群复筛,获得2株偏利共生协同真菌DPF2,DPF4,协同降解率最高,7d达87.77%。选择其进行室内油污土壤的微生物修复模拟试验,60d石油污染强度为10的油污土壤降解率最高,可达94.12%。污染强度为25的油污土壤降解率为90.17%,SPSS数据分析表明生物修复影响的最大影响因素是氧化剂、表活剂和营养物,其次是污染强度、接菌量。结论]初期添加表活剂、氧化剂、营养剂能对石油生物修复具有重要意义。污染强度仅在35d前有一定影响,在修复后期影响最小。在整个修复过程,接菌量方差均值与其他因素比较都最小,因此其因素水平对石油降解能力的影响不显著。

Screening of Microorganisms for Remediation of Oil-contaminated Soil and Its Influencing Factors

Objective] To reveal the relationship between the main influencing factors and the level (orthogonal design) of microbial in situ remediation in order to provide a theoretical basis for the parameter design of bio-remediation engineering in oil-contaminated sites.Methods] The effects of pollution intensity, nutrition, oxidant, surface active agent and inoculation amount on soil remediation were investigated by orthogonal design with 5 factors and 4 levels in the experiment.Results] After the preliminary screening of crude oil as the sole carbon source, 16 dominant bacteria strains for petroleum hydrocarbon degradation were obtained. By the bacterial rescreening, two symbiotic fungi DPF₂ and DPF₄ were obtained. The highest synergistic degradation rate was 87.77% after 7 days. The degradation rate of oil-contaminated soil was the highest when the oil pollution intensity was 10 after 60 days, and the degradation rate of oil-contaminated soil reached to 94.12%. The degradation rate of oil-contaminated soil with pollution intensity of 25 was 90.17%. SPSS data analysis showed that oxidants, surfactant and nutrients were the most important factors affecting bio-remediation, followed by the intensity of contamination and the number of bacteria.Conclusion] The initial addition of surfactant, oxidants, and nutrients could be of great significance to petroleum bio-remediation. The pollution intensity had a certain effect before 35 days, and had the least influence in the later stage of remediation. During the whole remediation process, the mean variance of inoculation amount was the smallest compared with other factors, so the factor level had no significant effect on the oil degradation ability.