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There is growing in interest in deploying nanoscale zero valent iron (NZVI) in permeable reactive barriers (PRBs) for groundwater remediation. In the present study a series of packed-column experiments were conducted in order to investigate the effectiveness of phosphorus removal from groundwater using NZVI and bimetallic NZVI/Cu as a reactive material within permeable reactive barriers (PRBs), also to help to inform on the design of the PRB. Experiments were conducted using a lab-scale column of 65 cm length and 10 cm inner diameter using two types of silica sand, river sand and standard sand, as a filling porous material. Seven sets of column experiments were established in order to investigate the effect of: different delivery methods of the reactive material into porous media (layers-packing or injection); modifying NZVI composition by copper addition; supporting materials and the flowrate change. The physical characteristics of the reactive and supporting materials were investigated using X-ray diffraction (XRD) analysis, transmission electron microscopy (TEM), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS).These analyses revealed that doping of NZVI surface with copper enhanced performance in terms of phosphorus removal 2.2 times more than pure NZVI. Moreover, the lower flowrate (10 ml/min) demonstrated improved phosphorus removal by 22 % compared with higher flowrate (60 ml/min). Additionally, the contact time between NZVI and phosphorus had a crucial effect on the long-term phosphorus removal efficiency and should to be considered in the preliminary design of PRBs. Overall, geochemical properties as well as the characteristics of the supporting materials were considered to be key parameters in the removal process of phosphorus by bimetallic NZVI/Cu. Further studies should be performed based on a statistical analysis model in order to integrate such presented results in the determination of the optimum design and conditions of PRBs towards better performance in the real in-situ remediation applications.

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