Site Characterisation for Landfill Construction in Tarkwa-Nsuaem Municipality, Ghana

摘要

Soil samples were taken from the Kaware Formation of the Tarkwaian Group forvarious analyses to characterise it for the design and construction of the first engineered landfillfor Tarkwa-Nsuaem Municipality in the Western Region of Ghana. The bulk geochemistry of thesoils was determined by XRF and ICP, mineralogy by XRD and geotechnical properties werealso determined. The soils were silty clayey sand (SM-CS), had a liquid limit of 22.1 and aplasticity index of 5.64. The average field moisture content was about 16.7% and the maximumProctor compaction dry unit weight was 18.7 kN/m~3 at an optimum moisture content of 11.6%.The average saturated hydraulic conductivity, Ks was 8.27 × 10~(-7) cm/s. The major oxides fromthe XRF analysis were SiO_2 (78.76%), Al_2O_3 (10.3 %) and Fe_2O_3 (3.2%). This gave a silicasesquioxide(S-S) ratio of 5.84 classifying it as a lateritic soil. The major mineralogy is quartz,kaolinite and muscovite which are consistent with a lateritic soil profile. The soil was permeatedwith landfill leachate during the hydraulic conductivity experiment for 11 days. The break through curves indicate that, most ions were initially desorbed from the soil into solution andlater adsorbed towards the end of the permeation indicating that the soils have long themattenuation capacity.