ATBU Journal of Science, Technology and Education, Vol 11, No 2 (2023)

Impact of Chelating Agents on Electrokinetic Remediated Crude Oil Contaminated Soil for Use in Road Construction

A. K. Abdulrrahman, K. Adebayo, J. E. Sani, I. I. Hassan, A. M. Anwar, G. Moses

Abstract


A lot of work has shown that electrokinetic remediation (EKR) technology can be enhanced by a number of strategies for more effective performance. The suitability of EKR soils for use in road construction have also not been well researched. This work presents the impact of chelants enhanced EKR crude oil contaminated soil (COCS) for use in road construction by comparing the performance of ethylenediaminetetraacetic acid (EDTA), citric acid and traditional (unenhanced) EKR. COCS collected at a depth of 1 m from the Nigerian Pipeline and Storage Company, Kaduna in Kaduna State was remediated by using graphite electrodes to pass 1 V DC/cm across EKR setups enhanced by using 0.2 M EDTA, 0.2 M citric acid and distilled water separately as anode purging solutions. The total petroleum hydrocarbon results showed that the crude oil content of 78,600 mg/kg present in the COCS exceeds permissible limits for soils. Average removal efficiencies of 36.74%, 21.37% and 80.61% obtained from EDTA, citric acid and distilled water enhancements respectively showed that distilled water, with highest removal efficiency, is a good anode purging solution for COCS than EDTA and citric acid chelants. The results of the geotechnical properties of the COCS showed slight improvement with the chelants enhanced EKR with best performance with distilled water EKR. The CBR and durability properties of the COCS and remediated soils do not meet the requirements for road construction uses. As such, EDTA, citric acid or distilled water enhanced EKR soils should not be used for road construction without stabilization.