Performance Evaluation of Compacted Lateritic Soil Bio-Cemented with Bacillus megaterium for Use as Liners and Covers in Municipal Solid Waste Containment

Laboratory evaluation of the bio-cementation effect of lateritic soil using MICP was carried out to determine the overall acceptable zone (OAZ) for its use. Lateritic soil was treated with B. megaterium up to 24 × 108 cells/ml over a range of moulding water contents (MWCs) from dry to wet sides of optimum moisture content (OMC) (i.e., −2%, 0%, +2%, and +4%). The soils were compacted with four energies [i.e., reduced British Standard light (RBSL) (Reduced Proctor), British Standard light (BSL) (Proctor), West African Standard (WAS) (Intermediate), and British Standard heavy (BSH) (Modified Proctor)]. The hydraulic conductivity (k ≤ 1.0 × 109 m/s), volumetric shrinkage strain (VSS ≤ 4%), and unconfined compressive strength (UCS ≥ 200 kN/m2) values that represent the design parameters for construction of liners and covers in MSW containment facilities were determined. It was found that lateritic soil treated with B. megaterium suspension density of 2.4 × 109 cells/ml prepared with MWC in the range 14.4%–16.4% and compacted with at least BSL energy is within the OAZ and satisfies landfill containment design criteria.