Groundwater protection from lead contamination using granular dead anaerobic sludge biosorbent as permeable reactive barrier

Abstract

This study investigated the performance of granular dead anaerobic sludge (GDAS) biosorbent as permeable reactive barrier (PRB) in removing lead from contaminated shallow groundwater. Batch tests were performed to characterize the equilibrium sorption properties of the GDAS and sandy soil in lead-containing aqueous solutions. Fourier transform infrared analysis proved that the carboxylic, alcohol, and alkyl halides groups were responsible for the biosorption of lead onto GDAS. A two-dimensional numerical model, solved by COMSOL Multiphysics 3.5a software, which is based on finite element method, was developed to simulate the equilibrium transport of lead within groundwater. This model considered the pollutant sorption onto the GDAS and sandy soil using Langmuir equation. Numerical and experimental results proved that the PRB plays a potential role in the restriction of the contaminant plume migration. Furthermore, the barrier started to saturate with contaminant as a function of the travel time, and thicker barrier was more efficient than thinner one. However, a good agreement between the predicted and experimental results was recognized with root mean squared error not exceeding 0.055.