ABSTRACT
Environmental pollution with petroleum and petrochemical products has been recognized as one of the most important and serious challenges facing environment engineers. Disposal from mechanic sites, accidental leakages from petroleum carrying ships, vandalization of pipelines, have all contributed to the current common oil pollution in Nigeria today.
The currently used physical and chemical remediation are effective for the degradation of petroleum products but the affected medium lose the desired properties. Apart, they frequently produce many hazardous compounds which are harmful for living beings. In contrast, bioremediation is effective in terms of safety of the desired properties, but long term tolerance studies are needed before it’s being recommended for large scale use.

Bioremediation of engine oil-polluted, and diesel polluted lateritic soil samples were carried out; using indigenous oil-degrading bacteria isolated from deliberately polluted soil samples. Isolates were subjected to biochemical tests, and identified as pseudomonas. The engineering properties of polluted samples were tested as the bioremediation proceeds. The result showed that the polluted samples regained almost all engineering properties on complete bioremediation of the polluted sample. Meanwhile, the rate at which the bioremediation takes place highly depends on the nature of the pollution. In this case, the rate of bioremediation of diesel-polluted sample is higher than that of the engine oil-polluted sample under the same condition.

CHAPTER ONE

INTRODUCTION
1.1           Background of the Research.
1.1.1. Bioremediation Concept: 
 
Bioremediation can be defined as any process that uses microorganism or their enzymes to reform the environment altered by contaminants to its original condition. Bioremediation may be employed in order to attack specific contaminants, such as oil spills that are broken down using multiple techniques including the addition of fertilizer to facilitate the decomposition of crude oil by bacteria. Such treatment will go a long way to improving the engineering properties of such soil and enhance its suitability.
Generally, bioremediation technologies can be classified as insitu or exsitu. Insitu bioremediation involves treating the contaminated material at the site while exsitu involves the removal of the contaminated material to be treated elsewhere.
Often, bioremediation can be accomplished without human intervention by microorganisms that are naturally found in the contaminated matrix.