Investigating the Influence of the Leachate from the Municipal Solid Waste on the Mechanical and Environmental Properties of Soil around the Landfill (Case Study: The Municipal Landfill Located in Ardabil—Iran)

Leachate is a very hazardous liquid, and it is considered as one of the major concerns regarding landfills. Landfill leachate is the result of water penetration from solid waste and oxidation of waste and parcels. The undeveloped landfills allow the leachate to cross easily through the soil. This can affect the soil engineering properties such as shear strength, soil compressibility and chemical properties (absorption and retention of heavy metals). This research has investigated the influence of the leachate resulted from municipal solid waste in Ardabil with different percentages and densities on the parameters of shear strength and compressibility of the soil around the site. Also, a test, which is called leachate column test, was carried out to study the environmental properties of the soil (the rate of pollutant absorption and pollutants transmission). The results indicate that with increasing leachate percentage, the internal friction angle decreases. Moreover, soil cohesion is significantly reduced and the compressibility results indicate that soil compressibility will also increase. Increasing the concentration of leachate reduces the cohesion and increases the internal friction angle as well as the compressibility, and changes the volumetric pressure of the soil. Also, the results of leachate test, which shows the rate of pollutants absorption and transmission in the sample placed in the chamber, indicate that the concentration of nickel and zing goes up by increasing the volume of the passing leachate.