Oil Water Remediation

We have a ​serious case of ​groundwater ​contamination ​at Nisisioken ​Ogale, in Eleme ​LGA. The pollution ​is due to the ​Nigerian ​National ​Petroleum ​Company product ​pipeline in ​proximity of ​which an 8 cm ​layer of ​refined oil was ​observed ​floating on the ​groundwater ​which serves ​the community ​wells.  ​ Total ​petroleum ​hydrocarbons (​TPH) are ​30,000 for the ​adjacent ​soil. ​ How can we ​most efficiently ​and economically ​remove the oil ​from the ​already ​contaminated ​groundwater? ​