Influence of real and synthetic municipal solid waste leachates on consolidation and shear strength behaviour of bentonites.

Abstract

For safe disposal of wastes in landfills, compacted bentonite is recommended as bottom liners due to their significant cation exchange (CEC) and swelling capacity, low permeability and large specific surface area (SSA). The present investigation carried out various experimental studies determining the compressibility behaviour and unconfined compressive strength (UCS) of two different compacted bentonites in the presence of municipal solid waste (MSW) and synthetic MSW leachates. Various examinations were conducted determining alterations in consolidation parameters like the coefficient of consolidation (cv), time taken for 90% consolidation (t90) and compression index (Cc) with both leachates. The outcomes reveal that Cc and t90 values of both bentonites declined; however, cv value rose. Results also indicated that under any given consolidation pressure, a lesser void ratio was achieved for leachates. UCS of both bentonites reduced with leachates' interaction yet, lying within the recommended a value higher than 200 kPa. A comparative assessment of the two bentonites displayed that bentonite having higher CEC and swelling capacity, and SSA unveiled more excellent Cc and t90 values and a reduction in the UCS. A higher variation in behaviour of bentonites was perceived in the existence of MSW leachate in comparison to synthetic MSW leachate.