title: Geochemical modelling for predicting the long-term performance of zeolite-PRB to treat lead contaminated groundwater.
abstract: The feasibility of using geochemical modelling to predict the performance of a zeolite-permeable reactive barrier (PRB) for treating lead (Pb(2+)) contaminated water was investigated in this study. A short-term laboratory column experiment was first performed with the zeolite (clinoptilolite) until the elution of 50 PV (1 PV=ca. 283 mL). Geochemical simulations of the one-dimensional transport of the Pb(2+), considering removal processes including: ion-exchange, adsorption and complexation; the concomitant release of exchangeable cations (Ca(2+), Mg(2+), Na(+), and K(+)) and the changes in pH were subsequently performed using the geochemical model PHREEQC. The results showed a reasonable agreement between the experimental results and the numerical simulations, with the exception of Ca(2+) for which a great discrepancy was observed. The model also indicated the formation of secondary mineral precipitates such as goethite and hematite throughout the experiment, of which the effect on the hydraulic conductivity was found to be negligible. The results were further used to extrapolate the long-term performance of the zeolite. We found the capacity would be completely exhausted at PV=250 (ca. 3 days). The study, thus, generally demonstrates the applicability of PHREEQC to predict the short and long-term performance of zeolite-PRBs. Therefore, it can be used to assist in the design and for management purposes of such barriers.
authors: Department of Geology and Environmental Protection, Hydrogeotechnika Sp z o.o., ul.Sciegiennego 262A, 25-112 Kielce, Poland. Electronic address: franklin.obiri.nyarko@hydrogeotechnika.pl.
authors: Franklin
authors: F
authors: Obiri-Nyarko
authors: Department of Spatial Planning and Environmental Sciences, Faculty of Geodesy and Cartography, Warsaw University of Technology, Pl Politechniki 1, 00-661 Warsaw, Poland.
authors: Jolanta
authors: J
authors: Kwiatkowska-Malina
authors: AGH University of Science and Technology, Department of Hydrogeology and Engineering Geology, Al. Mickiewicza 30, 30-059 Krakow, Poland.
authors: Grzegorz
authors: G
authors: Malina
authors: Department of Geology and Environmental Protection, Hydrogeotechnika Sp z o.o., ul.Sciegiennego 262A, 25-112 Kielce, Poland.
authors: Tomasz
authors: T
authors: Kasela
mesh_terms: D000327:Adsorption; D002412:Cations / Q000737:chemistry; D005290:Ferric Compounds / Q000737:chemistry; D060587:Groundwater / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007474:Ion Exchange; D058085:Iron Compounds / Q000737:chemistry; D007854:Lead / Q000737:chemistry*; D008903:Minerals / Q000737:chemistry; D008962:Models, Theoretical; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D014877:Water Pollution, Chemical; D018508:Water Purification / Q000379:methods*; D017641:Zeolites / Q000737:chemistry
chemical_list: D002412:Cations; D005290:Ferric Compounds; D058085:Iron Compounds; D008903:Minerals; D014874:Water Pollutants, Chemical; C083175:clinoptilolite; C094886:goethite; D017641:Zeolites; C000499:ferric oxide; D007854:Lead
keywords: Column experiment; Lead; Long-term performance; PHREEQC; Permeable reactive barriers; Zeolite