Removal Efficiency of Heavy Metals by Washing the Contaminated Soil Using Effective Leaching Agents

Unscientific disposal of industrial waste pollutes the surrounding soil and groundwater during the contamination of heavy metals through leachates. It has been observed from the sample tests conducted on soil and groundwater from various cities that the concentration levels are above the threshold levels. If not addressed, this will result in very serious consequences on the health of human beings and animals. Immediate action is required to prevent contaminated soils from further damage and reduce the contaminant concentrations in the soil. Many researchers have developed different soil remediation methods such as immobilization, phytoremediation, and soil washing. In this research work, an attempt has been made to establish more suitable leaching agents to wash the contaminated soil in bringing down the concentration. In the present study, the use of the soil washing technique with respect to zinc contaminated soil is demonstrated. Column leaching tests on contaminated soil samples were conducted to know the removal efficiencies with mono and combined chemical solutions. Contaminant transport parameters were determined using analytical method of plotting the elution curves of analytical and experimental values. It was observed from the results that leaching with 0.1 Normal Ferric Chloride (FeCl3) is very effective with a removal efficiency of 99.8% compared to the other chemical agents. Further study is very much required in this regard in different soils and for different heavy metals to treat the contaminated sites using soil washing technique.