A Review of the Hydraulic Performance of Permeable Reactive Barriers Based on Granular Zero Valent Iron

• Published in: Water (Basel) Vol. 15; no. 1; p. 200
• Main Authors: Bilardi, Stefania, Calabrò, Paolo Salvatore, Moraci, Nicola
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.01.2023
• Subjects: Analysis; Aquifers; By products; Climate change; clogging; column tests; Construction costs; Contamination; Environmental impact; Ethylenediaminetetraacetic acid; Geology; Granular materials; granular mixtures; Groundwater; Groundwater pollution; Groundwater treatment; heavy metals; hydraulic conductivity; Hydraulic design; Hydraulics; Hydrogeology; Iron; iron corrosion; Laboratory tests; Mathematical models; Numerical models; Performance evaluation; Permeability; Pollution prevention; Precipitation; Social impact; Sustainability; Technology application; Waste materials; Water, Underground
• ISSN: 2073-4441; 2073-4441
• DOI: 10.3390/w15010200

Permeable reactive barriers (PRBs) based on the use of zero valent iron (ZVI) represent an efficient technology for the remediation of contaminated groundwater, but the literature evidences “failures”, often linked to the difficulty of fully understanding the long-term performance of ZVI-based PRBs in terms of their hydraulic behavior. The aim of this paper is to provide an overview of the long-term hydraulic behavior of PRBs composed of ZVI mixed with other reactive or inert materials. The literature on the hydraulic performance of ZVI-based PRBs in full-scale applications, on long-term laboratory testing and on related mathematical modeling was thoroughly analyzed. The outcomes of this review include an in-depth analysis of factors influencing the long-term behavior of ZVI-based PRBs (i.e., reactive medium, contamination and the geotechnical, geochemical and hydrogeological characteristics of the aquifer) and a critical revision of the laboratory procedures aimed at investigating their hydraulic performance. The analysis clearly shows that admixing ZVI with nonexpansive granular materials is the most suitable choice for obtaining a long-term hydraulically efficient PRB. Finally, the paper summarizes a procedure for the correct hydraulic design of ZVI-based PRBs and outlines that research should aim at developing numerical models able to couple PRBs’ hydraulic and reactive behaviors.