Bioelectrokinetic approach for remediating loam soil contaminated with vegetable oil, mineral oil, and diesel.

Abstract

Bioelectrokinetic remediation integrates electrokinetic and bioremediation processes to enhance the removal of pollutants from the soil. This study evaluates the efficiency of bioelectrokinetic remediation in treating loam soils contaminated with vegetable oil, mineral oil, and diesel at a concentration of 20,000 mg/kg under low-voltage conditions (0.11 V/cm), aiming to maintain microbial activity while minimizing drastic pH fluctuations near the electrodes. A 14- day microcosm experiment was conducted, monitoring physicochemical parameters (pH, moisture content, contaminant distribution) and biological responses (heterotrophic aerobic bacteria, contaminant-degrading bacteria, fungi, and microbial enzymatic activity). The results demonstrated significant contaminant migration towards the anode for all three pollutants. Vegetable oil contamination showed degradation rates (average zones of 22.06%, central zone of 62.29% related to control), attributed to electromigration and increased microbial population and activity. A similar effect was noticed for diesel biodegradation (average zones of 15.23%, central zone of 64.50% related to control). In contrast, mineral oil exhibited no degradation and enhanced microbial activity, with a 29.89% reduction in the central zone related to the control, attributed exclusively to migration of pollutant to the anode. These findings lay the groundwork for developing optimized remediation strategies that maximize contaminant removal while preserving microbial activity, contributing to the advancement of sustainable soil restoration strategies.