Pilot-Scale Low-Cost Mixed-Media Permeable Reactive Barrier (PRB) System to Treat Heavy Metals in Groundwater Contaminated by Landfill-Leachate

Heavy metal (HM) is one of the notable contaminants that may contribute to groundwater pollution. Landfill-leachate is a source, discharging HMs to groundwater. It is essential to trap HMs in groundwater to avoid consequential adverse ramifications. Permeable Reactive Barrier (PRB) is an in-situ technique that can be adopted to remove HMs in groundwater contaminated by landfill-leachate. The objective of this study was to investigate removal efficiencies of HMs in groundwater contaminated by landfill-leachate using a pilot-scale PRB system. Dewatered Alum Sludge (DAS), Washed Sea Sand (WSS), Washed Quarry Dust (WQD), Red Soil (RS), Saw Dust (SD) and Bio Char (BC) were used as mixed reactive media in sequentially connected two PRB models. Average removal efficiencies of Pb, Mn, Cu, Cd and Fe were 94 %, 81 %, 71 %, 68 % and 68 %, respectively for 140 days of an experimental run. Treatment efficiencies could be stimulated by the presence of Fe, Al and Si oxides in materials. It is revealed that mixed-media PRB system showed a remarkable treatment efficiency without a significant change of material properties even after the increase of HM loading at the latter stage. This would also be an economically and environmentally sound re-use application for abundant waste materials.