Performance assessment of amended laterite soil as liner material in ash pond structures

Department of Civil Engineering, National Institute of Technology (NIT) Durgapur, Durgapur-713 209,

West Bengal, India

E-mail: shyamal64@gmail.com

Manuscript received online 02 February 2019, accepted 14 March 2019

The aim of the present study was to examine the effectiveness of locally available laterite soil (LS) as primary liner material in ash ponds to restrict subsurface migration of heavy metals such as Cd, Ni, and Zn etc. present in the leachate generated from ash ponds of Thermal Power Plants. Due to its high permeability (3.74×10^–5 cm/s) and moderate shear strength, laterite soil was further amended with commercially procured bentonite (B) and fly ash (FA) in the ratio of 8(LS):1(B):1(FA) to enhance its contaminants attenuating potential as liner material. The metal removal efficiency of the amended laterite soil was observed around 96% in case of cadmium metal. The results of fixed bed column experiment exhibit excellent heavy metal adsorption potential of amended laterite soil. The breakthrough curves (BTCs) generated by using HYDRUS-1D solute transport software shows good fitting with experimentally observed data.