CHEMICAL ENGINEERING TRANSACTIONS VOL. 28, 2012 A publication of The Italian Association of Chemical Engineering Online at: www.aidic.it/cet Guest Editor: Carlo Merli Copyright © 2012, AIDIC Servizi S.r.l., ISBN 978-88-95608-19-8; ISSN 1974-9791 Remediation of a Heavy Metals Contaminated Site with a Botanical Garden: Monitoring Results of the Application of an Advanced S/S Technique Petra Scanferla* a , Antonio Marcomini b , Roberto Pellay c , Pierandrea Girotto c , Dino Zavan c , Maurizio Fabris c , Amilcare Collina d a Consorzio Venezia Ricerche, via della Libertà 12, Marghera-Venice b Dept. of Environmental Sciences, Informatics and Statistics, University Ca’ Foscari, Dorsoduro 3246, Venice c Mapintec srl, via Romea 8, Mira-Venice d Mapei SpA, via Cafiero 22, Milan sp.cvr@vegapark.ve.it An innovative stabilization/solidification (S/S) technology called HPSS has been applied for the first time in a very delicate environment with a historical botanic garden in Venice for the remediation of a soil contaminated by heavy metals (As, Cu, Hg, Pb, Sb, Sn). This S/S technique, based on the High Performance Concrete (HPC) know-how (Scanferla et al., 2009), has been already successfully applied for the reconversion of different industrial contaminated sites into residential ones. The technology allows the remediation of contaminated soil fine fraction which is transformed into a very dense, low porous and mechanically-resistant granular material with the environmental characteristics for its reuse as filler in direct contact with the roots of the vegetal patrimony. More than 8,000 m 3 of contaminated soil fine fraction has been treated and monitored throughout 34 representative samples. Metal leachability was verified according to a leaching test method for granular waste (EN 12457-2, 2002) in which the demineralized water has been replaced with artificial sea water in accordance to Local Environmental Agency requirement. The mechanical properties were measured according to Los Angeles (LA) test method (BS EN 1097-2, 2010) for construction aggregates obtaining very good results in toughness and abrasion resistance. The granular material has been used tout court under the final floor layer in transit way and mixed with compost and soil in green areas also beside the rhizosphere horizon. 1. Introduction Soils are the major sink for heavy metals released into the environment by many different anthropogenic activities and unlike organic contaminants which are oxidized to carbon oxide by microbial action or other type of natural attenuation, most metals do not undergo microbial or chemical degradation and their total concentration in soils persists for a long time after their introduction such as in the case of different filling material used in the past for the land raising of same part of Venice. The adequate protection and restoration of soil ecosystems contaminated by heavy metals require their remediation in relation to the risks and hazards posed by these contaminants to humans and the ecosystem (Wuana and Okieimen, 2011), even if the contamination takes its origin long time ago. Immobilization, soil washing, and phytoremediation techniques are frequently listed among the best demonstrated available technologies (BDATs) for remediation of heavy metal-contaminated sites. 235