Plant-microbial Remediation For Crude Oil Contaminated Soil Under Different Salt Content

With increased yield and consumption of crude oil, it is inevitable to enter soil environment and to contaminate the soil. Once crude oil mixing with soil, the physical and chemical characters of soil will be changed and permeability of the soil voids will be blocked. Meanwhile, as a complex compound, aromatic compounds in the crude oil take a large proportion, especially for PAHs, which can cause carcinogenic, teratogenic and mutagenic, all of these will run a high risk to animals, plants and microbes in the soil.Plant-microbial remediation as a fast, efficient and non-secondary pollution treatment has been applied remediation of crude oil contaminated soil commonly. Based on the salinity character of soil in Tianjin, crude oil contaminated soil remediation under high salt concentration by using plant-microbial method can provide theories for restoring in-suit soil directly. In this test, three salt contents, including 2493mg/kg, 3690mg/kg and 4666.67mg/kg, three crude oil contents, including 5000 mg/kg, 10000 mg/kg and 15000mg/kg are designed to study crude oil degradation rate in the pot experiments by applying plant-microbial combined method, the main conclusions are listed:Through comparison of non-root group, plant group and plant-microbe group, it shows that the degradation rate under 5000mg/kg crude oil is plant group10000mg/L>50000mg/L. However, the final degradation rate of crude oil in the fungus flora is lower than that of in the bacteria flora. The same conclusions of DHA and total microbial amount in the flask are resulted.It is worth to point out that pH in both bacteria flora and fungus flora has changed greatly from neutral/acidic to alkaline. However, an exact explanation to this phenomenon cannot be concluded now.Through PCR-DGGE analysis, the main strain is increased as crude oil content increasement and the strength of these main strains is increased as well. Meanwhile, the structure and complex of bacteria and fungus flora become more and more diverse as crude oil increasement by observing other stains in each flask system.