Removal of heavy metals from leachates using permeable reactive barriers filled with reactive organic/inorganic mixtures

In the present experimental study the efficiency of permeable reactive barriers (PRBs) containing organic material and limited quantities of zero valent iron, fly ash or red mud to remove heavy metals from leachates was assessed. Upflow laboratory column experiments were carried out to study the efficiency in terms of Cu, Zn, Ni and Mn removal. The columns were filled with each reactive mixture and packed slightly to simulate field conditions; synthetic solutions with initial concentration of 50 mg/L of each metal were used. Column effluents were sampled periodically and analyzed for pH, oxidation-reduction potential, sulphate and metals concentration. The experimental results show in most cases adequate metal removal efficiency. XRD analyses were used to elucidate the main removal mechanisms involved.