Effects of Salt on the Lead Adsorption and Migration in Marine Clay

— Application of natural clay liner to coastal landfill sites —

Abstract

In the present study, column and batch tests have been conducted to assess the adsorption ability of lead by marine clay in the presence of salt using lead-spiked DI water, artificial seawater and incinerated ash leachate. Moreover, the migration of lead in the ground where the bottom barrier of coastal landfill sites is assumed is predicted by using the retardation coefficient obtained from the both tests, and refers to the application to the bottom barrier of the coastal landfill sites. Both tests indicate that though the lead adsorption ability is high in the DI water, and decreases in the artificial seawater and the incinerated ash leachate including salts as the concentration of salts rises. Using the adsorption isotherm from batch and column test, prediction of migration of Pb was conducted assuming the bottom barrier of coastal landfill site with HYDRUS-1D. In case of initial concentration of Pb, the result of prediction for column test was evaluated 2.7 times higher than batch test. This is the reason why a column test could consider the pore structure of Marine clay for the evaluation of adsorption.