Petroleum hydrocarbon contaminated groundwater remediation using 21st century technology: Baruwa community, Lagos State Nigeria as a case study

This research focused on geo-environmental site assessment and remediation of contaminated soil/groundwater. Baruwa community is the study site and it is located at Alimosho Local government area of Lagos state, Nigeria. About 350 hand dug wells for domestic water supply are in the community, all the wells are contaminated with petroleum product from leaking underground pipeline that transverse the community. Free hydrocarbon product thickness up to 0.72m was found on top of the groundwater in the hand dug wells. The main objective of the project was to take a hectare (100m x 100m) of the most contaminated area and remediate the groundwater to permissible level using the most up-to-date equipment and technology. Integrated Remediation Approach (IRA) was utilized; this involves physical and chemical method. The physical method involves the use of skimming-off technology that draws out the pure non-aqueous phase liquid (PNAPL) from the hand-dug wells. Chemical method adopted was in-situ chemical oxidation (ISCO), which involves injecting oxidizing agent (KMnO₄) to the groundwater in the hand dug wells. Notable deplection in the values of TPH from a maximum of 500ppm to 20, 0, 25, 6, 6, 0.7 ppm for the six monitored wells during the 30 weeks of observation.