1,720,973 research outputs found
Performance assessment and monitoring of groundwater remediation by a permeable reactive barrier
No full textProgettazione, realizzazione e monitoraggio della prima PRB italiana a trincea continua
No full textDescrizione dell'installazione della prima barriera reattiva permeabile presso un sito contaminato ad Avigliana in provincia di Torin
Construction and monitoring of a permeable reactive barrier near the city of Torino in Italy
No full textThe aim of this study is to describe the first full scale application of a zerovalent iron permeable reactive barrier in Italy and illustrate the preliminary results of the monitoring plan. The PRB was designed and emplaced to remediate a chlorinated hydrocarbons plume at an old industrial landfill site, in Avigliana, near the city of Torino, in the Piemonte region. The installation of the 120 m long, 13 m deep and 0.6 m thick barrier was accomplshed using a clamshell for the excavation of the trench and a guar gum slurry to support the walls. After a description of the intervention, preliminary results of the monitoring plan are presente
Monitoraggio post operam e della funzionalità a lungo termine della barriera reattiva permeabile di Avigliana (To)
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Contaminazione da nichel in acquiferi a valle di discariche perdenti
No full textNelle acque sotterranee la presenza di nichel in concentrazioni elevate è frequentemente legata ai fenomeni di contaminazione da percolato di discarica. Infatti, l'apporto di sostanze organiche, attraverso processi di complessazione e di ossidoriduzione, può comportare una dissoluzione del nichel, e dei metalli pesanti in genere, presente in fase solida nel sottosuolo. Il presente lavoro descrive brevemente i processi geochimici che influenzano il trasporto del nichel nelle acque sotterranee e propone una descrizione matematica di tali fenomeni, attraverso una correlazione empirica fra le concentrazioni di Ni, Fe e Mn. Ciò costituisce uno strumento immediato ed efficace per stimare la distribuzione del Ni nel mezzo saturo, una volta rilevati, o calcolati con modello deterministico, i campi di concentrazione di Fe e M
Performance evaluation of permeable reactive barrier using zero-valent iron at a chlorinated solvents site
No full textThe present study illustrates the preliminary results of a long-term monitoring plan carried out in order to investigate the performance of a zero-valent iron permeable reactive barrier (PRB) at a chlorinated solvents’ site. The cleanup intervention has been undertaken at an industrial landfill located near the city of Turin (Italy) and represents the first full-scale application of this technology in Italy. The monitoring plan started in November 2005 with the aim to verify the attainment of the cleanup goals and to evaluate the efficiency of the PRB. The concentrations of the chlorinated compounds have been measured in a monitoring network across the PRB in order to assure that the dissolved plume is being adequately captured and treated without occurring of contaminant bypass/breakthrough. The hydraulic and chemical performances of the barrier are also monitored with the analysis of groundwater hydrochemistry with the purpose to evaluate the influence of secondary reactions (e.g. precipitation, microbially-mediated redox transformation). The medium and long-term effects of these processes on the PRB performances are simulated using geochemical equilibrium models
Biogeochemical characterization of zerovalent iron reactive barriers
No full textIn this study, we have investigated the geochemical processes taking place within a Fe0 barrier at the field installation of Avigliana, near the city of Turin in Italy, which represents the first full-scale application of this technology in Italy (Di Molfetta & Sethi, 2005
Hydrogeochemical and biological processes affecting the long-term performance of an iron based permeable reactive barrier
No full textDespite the wide diffusion of zero-valent iron (Fe0) permeable reactive barriers (PRBs), there is still a great uncertainty about their longevity and long-term performance. The aim of this study is to investigate the biological and the hydrogeochemical processes that take place at a Fe 0 installation located in Avigliana, Italy, and to derive some general considerations about long-term performance of PRBs. The examined PRB was installed in November 2004 to remediate a chlorinated solvents plume (mainly trichloroethene and 1,2-dichloroethene). The investigation was performed during the third year of operation and included: (1) groundwater sampling and analysis for chlorinated solvents, dissolved CH4, dissolved H2 and major inorganic constituents; (2) Fe0 core sampling and analysis by SEM-EDS, XRD, and FTIR spectroscopy for the organic fraction; (3) in situ permeability tests and flow field monitoring by water level measurements. The study revealed that iron passivation is negligible, as the PRB is still able to effectively treat the contaminants and to reduce their concentrations below target values. Precipitation of several inorganic compounds inside the PRB was evidenced by SEM-EDS and XRD analysis conducted on iron samples. Groundwater sampling evidenced heavy sulfate depletion and the highest reported CH 4 concentration (>5000 μg/L) at zero-valent iron PRB sites. These are due to the intense microbial activity of sulfate-reducers and methanogens, whose proliferation was most likely stimulated by the use of a biopolymer (i.e. guar gum) as shoring fluid during the excavation of the barrier. Slug tests within the barrier evidenced an apparent hydraulic conductivity two orders of magnitude lower than the predicted value. This occurrence can be ascribed to biofouling and/or accumulation of CH 4(g) inside the iron filings.This experience suggests that when biopolymer shoring is planned to be used, long-term column tests should be performed beforehand with initial bacterial inoculation and organic substrate dosing, in order to predict the eff ects of bacterial overgrowth and gas generation. During construction particular care should be taken in order to minimize the amount of used biopolymer so that complete breakdown can be achieve
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