Remediation of Oil Contaminated Sediment in Systems Characteristic of Nigeria's Niger Delta: North American Experience

Groundwater is of paramount importance globally, of which in Nigeria, more than 80% of Nigerians depend on groundwater as a source of drinking water and domestic uses, as well as for irrigation and production of goods. Globally groundwater has been polluted by biological, chemical and physical processes as a result of careless disposal and discharge of chemicals; through industrial (mainly through mining and petroleum) and agricultural activities operations; and through materials and structures on the earth’s crust, of which the contaminants percolate and seep into the soils and aquifers to contaminate the groundwater system and water supply. In order to clean up the contaminated groundwater system, the use of microbial degradation process to detoxify environmental contamination (bioremediation) was first applied to petroleum hydrocarbon contaminated groundwater systems in the early 1970s, of which in current practice, intrinsic bioremediation of petroleum hydrocarbons requires a systematic assessment to show that ambient natural attenuation mechanisms are efficient enough to meet regulatory requirements and a monitoring program to verify that performance requirements are met. Nigeria’s Niger Delta is one of the largest deltas in the world, the largest wetland in Africa and also maintains the third largest drainage basin in Africa, with the environment being broken into four ecological zones, namely: coastal barrier islands, mangrove swamp forests, freshwater swamps, and lowland rainforests. This is why the delta is highly polluted like other deltas and gulfs in the world. The oil contaminated sediment systems in Nigeria’s Niger Delta occur as a result of both point source pollution and non-point source pollution. It is a point source pollution because the contamination case usually originates from damaged tanks and pipelines at petroleum facility sites and non-point source pollution because the chemical contaminants spread out across wide areas and easily reach the groundwater without the help of infiltrating water.