Bonifica di un acquifero contaminato mediante barriera reattiva permeabile a ferro zerovalente

The aim of this study is to describe the construction and realization of the first full scale application of a zerovalent iron permeable reactive barrier in Italy. The PRB was designed and realized to remediate a chlorinated hydrocarbons plume at an old industrial landfill site, in Avigliana, near the city of Torino, in the Piemonte Region. The dimensioning of the PRB was conducted by means of a three dimensional flux and multispecies contaminant transport model based on column degradation test. The excavation of the 120 m long, 13 m deep and 0.6 m thick barrier, was performed using a crawler crane equipped with an hydraulic grab and supported by guar gum slurry. After the excavation, the trench was backfilled with 1700 t of iron and the biopolymer degraded using enzymes. The performance of this technique was outstanding and allowed the installation of the PRB in 7 days. The final configuration of the site will be characterized by a wide car park, a ciclo-cross track and a green capping to prevent the infiltration of water from the ground surface to the shallow aquifer.