Free Swell Potential of Selected Lateritic Soils Exposed to Municipal Solid Waste Leachate

Abstract

Tests were conducted to investigate the effect of Municipal Solid Waste (MSW) leachates on free swell potential of lateritic soils. Series of experiments namely, particle size distribution analysis, Atterberg limits and compaction tests were performed for characterization of five selected soils and free swell tests conducted with tap water and MSW leachates; Leachate 1, Leachate 2 and Leachate 3 from active open dump landfills in Minna. The preliminary test results showed that the five selected soils designated as soil M1, M2, M3, M4 and M5 were classified as A-2-7, A-4, A-5, A-6 and A-7-5 respectively according to AASHTO classification method. Typical of lateritic soils, plasticity index of soils ranged from 9 – 15% while the maximum dry density varied from 1.6 – 1.8g/cm3 with corresponding optimum moisture content of between 15 – 24%. For the free swell test, Soil M5 exhibited maximum free swell of about 20 and 12% when interacted with tap water and the leachates respectively. On the other hand, Soil M1 which swelled the least yielded swell values that reached 4.5 and 3.8% when hydrated with tap water and the leachates respectively. Intermediate amounts of swell were recorded for M2, M3, M4 soils exposed to both tap water and MSW leachates. Correlation between PI and free swell was established with R2 of 72%. The outcome of this study is important for many applications, especially in the use of these soils in landfill liner applications.