A new soil improvement method known as microbial induced calcite precipitation (MICP) has received tremendous attention of researchers in the related fields. This paper reports the results of the compatibility of compacted bio-cemented lateritic soil with municipal solid waste (MSW) leachate. Lateritic soil was treated with Sporosarcina pasteurii (S. pasteurii) suspension densities up to 2.40 x 10 9 cells/ml and compacted using British Standard light, BSL (or standard Proctor) energy. The permeation with leachate only yielded minimum hydraulic conductivity values of 5.02 x 10 -10 m/s for the natural soil and 5.78 x 10 -10 m/s for specimen treated with S. pasteurii suspension density of 2.40 x 10 9 cells/ml. The micrographs of specimens treated with S. pasteurii suspension density of 2.40 x 10 9 cells/ml and permeated with leachate only depicted the development of bio-film when compared with micrograph of the untreated soil. Test results showed significant reduction in the concentration of the MSW leachate chemical specie considered after interaction with S. pasteurii for 150 days either through bio-transformation or bio-degradation process.

The diffusion of municipal solid waste (MSW) contaminants in compacted lateritic soil-Bacillus coagulans (B. coagulans) mixture was studied. Diffusion test for single reservoir, decreasing source was adopted. Soil samples were treated with B. coagulans at one-third (1/3) pore volume in stepped suspension density of 0, 1.5 × 10 8 , 6 × 10 8 , 1.2 × 10 9 , 1.8 × 10 9 and 2.4 × 10 9 cells/ml, respectively, before compaction. Specimens were prepared at optimum moisture content (OMC) of British Standard heavy (BSH) compaction energy. Cementation reagent containing 3 g Nutrient broth, 20 g urea, 10 g NH 4 Cl, 2.12 g NaHCO 3 and 2.8 g CaCl 2 per litre of distilled water was injected by gravity in three (3) cycles of 6 hours interval into the compacted specimens. Thereafter, the specimens were sealed at the top with plastic sheets with small openings for the sequential introduction of water and leachate for 21 days and 69 days, respectively, to simulate field condition. Results obtained show that diffusion testing water content, pH and electrical conductivity within the soil column decreased with depth. Generally, all the cations considered had diffusion coefficient (D * ) and tortuosity factors ( a ) values that increased with increase in B. coagulans suspension density. However, Mg 2+ had value that initially decreased from 5.98 × 10 -9 at 0 cells/ml to a minimum value of -4.30 × 10 -8 at 1.5 × 10 8 cells/ml and thereafter increased to 1.64 × 10 -9 at B. coagulans suspension density of 2.4 × 10 9 cells/ml. The apparent D * and  a values for the anions considered initially decreased to a minimum and thereafter increased. The pore fluid concentration profile for the numerous chemical classes tested showed that the compacted lateritic soil -B. coagulans mixture can attenuate K + and Clions in MSW containment application.