Simulated AMD solutions of low and high metal ion concentration were pumped at different flow rates into the
laboratory system. Concentration profiles under steady-state transport conditions were developed by measuring metal ion concentration
at various sampling ports. Results show that metal ion removal is mainly accomplished via redox reactions that initiate precipitation of
mineral phases. Sulfate green rust was identified from the analysis of precipitates formed on the iron surface; sulfate and heavy metals
uptake by green rust is a secondary clean up mechanism. Experimental results as well as geochemical modeling by PHREEQC-2 indicate
that cadmium and copper are removed by redox reactions while aluminum, manganese, nickel, cobalt and zinc are mainly removed as
metal hydroxides. It is therefore seen than zero-valent iron barriers can be used as an environmentally and economically viable remediation
technology for the clean up of acidic leachates loaded with several inorganic contaminants and sulfates and the subsequent prevention
of groundwater contamination.