Abstract: Pollution is one of the major factors hindering the effective soil’s engineering applications. This research evaluated the possibility of remediating spent vehicle engine oil contaminated soil with rice husk ash (RHA) and groundnut shell ash (GSA). The soil samples geotechnical properties (California bearing ratio “CBR”, maximum dry density “MDD” and optimal moisture content “OMC”), and electrical properties (electrical conductivity “EC”, dielectric constant “ɛʹ” and dielectric loss factor “ɛʹʹ”), were determined in accordance with American Society for Testing and Materials (ASTM) approve guidelines. Results obtained from the laboratory tests depicted that both the contaminant and remediation materials have significant effect on all the investigated soil engineering properties. After the contamination, the geotechnical properties – MDD, OMC and CBR – decreased from 1.75 to 1.54 g/cm3, 16.55 to 14.76%, and 42% to 27%, respectively. Likewise, the electrical properties – EC decreased from 3.91 to 2.17 dS/m, while the ɛʹ and ɛʹʹ increased from 5.29 to 8.43, and 0.62 to 1.05, respectively. Then after the bioremediation program, the results revealed that the CBR and OMC values of the contaminated samples increased remarkably; while the MDD of the contaminated soil decreased considerably. It was noted that the ɛʹ values of the soil remediated with 1, 2, and 3% RHA were 3.23, 3.58 and 3.89, respectively; while samples amended with 1, 2 and 3% GSA recorded ɛʹ values of 3.05, 3.24 and 3.68 respectively. Furthermore, the samples treated with 1, 2 and 3% of RHA had ɛʹʹ values of 1.15, 1.23 and 1.34 respectively; and samples treated with 1, 2 and 3% of GSA developed ɛʹʹ values of 1.09, 1.18 and 1.29 respectively. These results are indications that GSA and RHA can be used to clean up polluted soils; hereby, restoring the contaminated soil’s electrical and geotechnical properties.

Leave a Comment