ABSTRACT

A bioremediation study was canied out on soil experimentally polluted with Bonny Light crude oil by supplementation with organic and inorganic nutrients (poultry manure, goat dung, sawdust and NPK fertilizer). The efficacy of the treatments was monitored for I I2days by the measurement of total heterotrophic and hydrocarbon utilizing bacteria and fungi, and some physico-chemical parameters. The polluted soil had mean bacterial counts of 8.8x104, 9.0x104, 9.2x l0, 9.9x104and 7.6x104cfu/rnl respectively. Sample treated with NPK fertilizer had mean bacterial counts of 4.4x104, 4.6x104, 4.7x104, 4.9x104and 5.2x104cfu/ml on days 0,28,56,84 and 112 respectively; sample treated with poultry manure had mean bacterial counts of 1.6x104, 1.8x104, 2.0x104, 2.4x104and 2.7x104cfu/ml on days 0, 28,56,84 and 112 respectively; the saw dust treated sample had mean bacterial counts of 2.0x104, 2.3x104, 2.7x104, 2.9x104and 3.0x104cfu/ml on days 0,28,56,84 and 112 respectively while that treated with goat dung had mean bacterial counts of 9.3x104, 9.5x104, 9.6x104, 9.8x104and 9.9x104cfu/ml on days 0,28,56,84 and 112 respectively. Mean counts of heterotrophic fungi increased in the control, control + poultry manure and control + saw dust samples and reduced in the control + NPK and control + goat dung samples. There were differences in the physico-chemical analyses from the diverse samples. The hydrocarbon-utilizing bacterium isolated was Acinetobcicter sp while the hydrocarbon utilizing fungi isolated included the following: Pen icillium sp, Cladosporiwn sp and Acreinoniuin sp. After statistical analysis (P~0.05) there was a significant difference between the different treated samples from the control. The results suggest that nutrient supplementation would be effective in the remediation of crude oil polluted soils.