Immobilization Remediation of a Heavy Metals Contaminated Soil: A Case Study of Dump Site at Bangalore, India

The soil remediation techniques play an important role when concerned with the environmental pollution caused by landfills, open dumps, mining areas and chemical spills. This paper aims to investigate the efficiency of inorganic and organic amendments to immobilize the heavy metals in a contaminated soil located at the Bingipura landfill site, Bangalore, India. The landfill site soil contaminated with heavy metals, i.e., copper, zinc, iron, chromium, cadmium, nickel and lead was studied with immobilization technique as this technique is relatively easily applicable and low cost. The immobilization efficiencies achieved with inorganic amendments, i.e., lime, cement, sodium hydroxide and organic amendments such as sawdust, arecanut fiber and dry leaves corresponding to pH values of 7.0, 8.5 and 10 were analyzed. The long-term efficiencies of organic and inorganic mixtures were assessed by conducting leaching tests on the stabilized soil for three months. The percentage leaching of various heavy metals from amended soil using different mixtures was observed during this period and the immobilization efficiencies were estimated. The highest immobilization efficiency was obtained using an admixture of lime with 5% sawdust corresponding to a pH value of 10. The leachability orders of different heavy metals from the amended soil were compared with the standard sequences of solubility of their hydroxides and found that the results were similar to these sequences. © 2021, The Institution of Engineers (India).