Abstract

This study examined the application of the Analytic Network Process (ANP), a multi-criteria decision analysis tool, in the selection of the best bioremediation technique for the remediation of a hydrocarbon-polluted site at Kwawa (4°36'29.26''N, 7°28'55.70''E) in Ogoniland, Niger Delta province, Nigeria. The decision-making problem involved four bioremediation techniques (that is, landfarming, field biopiles, thermal desorption, and phytoremediation) as well as four selection criteria (that is, health and safety, technical feasibility, regulatory requirements, and site-specific characteristics) and their twelve selection sub-criteria. The ANP evaluation involved pairwise comparisons of the remediation alternatives, selection criteria, and selection sub-criteria. Judgement matrices including unweighted supermatrix, weighted supermatrix, and a limit matrix were developed. The alternative with the highest priority vector at convergence was selected as the best. Result showed that phytoremediation with the highest priority vector of 0.1054 was the most appropriate remediation alternative for the study site. Additionally, site-specific characteristics with highest priority vector of 0.1636 was the most important selection criteria while type of soil with highest priority vector of 0.0625 was the most influential selection sub-criterion for the study site. This suggests that the ANP promises to be a veritable decision-support tool for the selection of the most appropriate bioremediation method for petroleum-contaminated sites in the Niger Delta province, Nigeria.

Key words:  Multi-criteria decision analysis, land contamination, bioremediation.