| The overall objective of the project is to develop a new method of bioremediation that, besides other controlling factors, will take into account the geochemical and geotechnical characteristics of soils for remediation of petroleum-contaminated soils. The project aims at identifying the most suitable soil type in terms of its geochemistry and physical properties and determining its control on bioremediation potential of petroleum-contaminated soil, utilizing both microorganisms and plants.; Soil is one of the key components of a bioremediation system. It is this medium that promotes the growth of both plants and microorganisms. It would, therefore, be expected that research on bioremediation should take into account the influence of soil chemistry and physical properties, in addition to the type of plants and microorganisms and related factors. This aspect, however, has not received much attention of researchers in the bioremediation field, which led to the development and formulation of the proposed study.; The research utilized a consortia of oil-degrading bacteria commonly found in petroleum-contaminated soils, along with three species of plants—alfalfa, mustard and tall fescue—in various combinations, to evaluate their potential in cleaning up petroleum contamination. Four different soil types—silt, silt loam, loam and sandy loam—were utilized in the lab-scale experiment. The experiments were conducted according to a full factorial design with three factors (PLANT with 3 levels, SOIL with 4 levels, BACTERIAL ACTIVITY with 2 levels). The Analysis of Variance (ANOVA) was used to perform statistical analyses of the data. The contamination degradation reactions followed a second-degree equation pattern. The statistical analyses of data showed presence of strong statistical significance between the soil-plant interaction, plant-bacteria interaction and also between soil-bacteria interaction. It was also observed that individually tall fescue and mustard in association with a consortium of pre-isolated oil-degrading bacteria were most effective in remediating contaminated silt-loam soil. Three isolated bacterial species (Pseudomonas , Bacillus, Benzene-decomposing bacterium S24) were reported in prior literature for their oil degrading capability, while the other three bacterial species were unknown for their oil degrading capability. |
