Influence of Microbial-Induced Calcite Precipitation on Compaction Characteristics of Bioremediated Crude Oil Contaminated Soil using Composting Technique

Abstract

Compaction as a soil improvement method of improving the engineering performance of soil was carried out on remediated contaminated soil with the aim of assessing the influence of microbial induced calcite precipitation (MICP) on compaction characteristics. Autochthonous bacteria was identified as Bacillus licheniformis and isolated from oil contaminated soil, collected from Kaduna refinery at Area W where the crude oil was stored. The bacteria were enhanced with organic liquid nutrient extracted from chicken droppings (CD) in stepped concentration of 10, 20, 30, and 40% by dried weight of soil sampleand used to hydrate the contaminated soil. The mixtures were kept in four microcosms for 3 months. The initial total hydrocarbon content was 98g/kg. The bioremediated soil was treated with bacteria solution through MICP technique. The results revealed that sample treated with 30% CD yielded the highest removal efficiency of 89.8% of oil removal. Maximum Dry Density increased with addition of B. licheniformis solution to a peak value of 1.93Mg/cm3 for sample treated with 1.5×108 cell/ml. Optimum moisture content (OMC) increased with increased in B. licheniformis suspension from 14.4 to 15.8% when treated with 1.5×108 and 2.4 ×109 cell/ml respectively. Compaction characteristics of soil treated with 30% CD were greatly improved at 1.5×108 cell/ml bacteria solution using MICP technology and could be used as liner material in waste management.