Geotechnical properties of hazardous landfill leachate-contaminated sand

Abstract

Many industrial activities dispose of their waste in the sand soil of the El-Khatatba region of Egypt. There is a need to reuse the site in building markets and shopping stores. Because it is difficult to obtain leachate from an open dumping site, we use hazardous landfill leachate (HLL) from an industrial waste landfill to identify changes in the geotechnical properties of soil. The HLL was obtained from Al-Nasreya Center, Alexandria, Egypt. This study, therefore, was directed to assess the effects of HLL on the geotechnical properties of the poor-graded sand (SP) soil. The natural sand was artificially mixed with HLL at different concentrations of 0%, 25%, 50%, 75%, and 100%. The results revealed that the permeability coefficient (k) of the natural sand decreased significantly from 1.28 × 10−2 to 0.8 × 10−2 cm/s when HLL concentration increased to 100%. Similarly, HLL contamination obviously reduced the angle of internal friction (φ) of sand. The optimum moisture content (OMC) of the natural sand decreased from 12 to 10%. In contrast, the maximum dry unit weight (MDD) of the natural sand increased slightly from 18.33 to 18.9 kN/m3 due to the increase of HLL concentrations from 0 to 100%. The change in the sand structure was interpreted by detailed analyses using scanning electron microscopy (SEM) and X-ray diffraction (XRD). Based on these findings, HLL was found to modify the geotechnical properties of the studied sand.