Application of zero-valent iron/peat permeable reactive barrier for in-situ remediation of lindane and chlorobenzenes

Post pesticides production landfills are often a source of large uncontrolled contamination of groundwater. Therefore, there is a need to find suitable technologies to reduce the concentration and ecotoxicity of these pesticides. In this paper, both lab-and field-scale technology of permeable reactive barrier (PRB) for the treatment of hexachlorocyclohexanes (HCHs) and chlorobenzenes (CBs) at a site in Jaworzno, Poland are described. The results showed the high efficiency of the treatment process for hexachlorocyclohexane (90%) and chlorobenzenes (99%) in lab-scale which slowly decreased to 86% and 97%, respectively with the time of PRB operation (112 d). The efficiency of treatment of HCHs and CBs by PRB technology in pilot scale in the 8th day operation was ca. 82% and 60%, respectively during the first phase of operation and highly decreased after two months of operation due to the loss of sorption capacity of peat bed and the passivation process of iron chips. Base on the measured data, it could be determined that the treatment train in such barrier relies on subsequent reductive dehalogenation and adsorption. Therefore, the results obtained and presented in this paper could be useful for further design of full-scale permeable reactive barriers on sites with groundwater contaminated by similar organochlorine pesticides.