Pilot tests for the optimization of the bioremediation strategy of a multi-layered aquifer at a multi-focus site impacted with chlorinated ethenes
Blázquez Pallí, Natàlia (LITOCLEAN, S.L.)
Torrentó, Clara (Universitat de Barcelona. Departament de Mineralogia, Petrologia i Geologia Aplicada)
Marco Urrea, Ernest (Universitat Autònoma de Barcelona. Departament d'Enginyeria Química, Biològica i Ambiental)
Garriga, David (LITOCLEAN, S.L.)
González, Marta (LITOCLEAN, S.L.)
Bosch, Marçal (LITOCLEAN, S.L.)

Data:	2024
Descripció:	68 pàg.
Resum:	A multi-layered aquifer in an industrial area in the north of the Iberian Peninsula is severely contaminated with the chlorinated ethenes (CEs) tetrachloroethylene, trichloroethylene, cis-1,2-dichloroethylene, and vinyl chloride. Both shallow and deep aquifers are polluted, with two differentiated north and south CEs plumes. Hydrogeochemical and isotopic data (δ13C of CEs) evidenced natural attenuation of CEs. To select the optimal remediation strategy to clean-up the contamination plumes, laboratory treatability studies were performed, which confirmed the intrinsic biodegradation potential of the north and south shallow aquifers to fully dechlorinate CEs to ethene after injection of lactate, but also the combination of lactate and sulfidized mZVI as an alternative treatment for the north deep aquifer. In the lactate-amended microcosms, full dechlorination of CEs was accompanied by an increase in 16S rRNA gene copies of Dehalococcoides and Dehalogenimonas, and the tceA, vcrA and bvcA reductive dehalogenases. Three in situ pilot tests were implemented, which consisted in injections of lactate in the north and south shallow aquifers, and injections of lactate and sulfidized mZVI in the north deep aquifer. The hydrogeochemical, isotopic and molecular analyses used to monitor the pilot tests evidenced that results obtained mimicked the laboratory observations, albeit at different dechlorination rates. It is likely that the efficiency of the injections was affected by the amendment distribution. In addition, monitoring of the pilot tests in the shallow aquifers showed the release of CEs due to back diffusion from secondary sources, which limited the use of isotopic data for assessing treatment efficiency. In the pilot test that combined the injection of lactate and sulfidized mZVI, both biotic and abiotic pathways contributed to the production of ethene. This study demonstrates the usefulness of integrating different chemical, isotopic and biomolecular approaches for a more robust selection and implementation of optimal remediation strategies in CEs polluted sites.
Ajuts:	Agencia Estatal de Investigación PID2022-138929OB-I00 Agencia Estatal de Investigación PID2022-139911OB-C4-1
Drets:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, i la comunicació pública de l'obra, sempre que no sigui amb finalitats comercials, i sempre que es reconegui l'autoria de l'obra original. No es permet la creació d'obres derivades.
Llengua:	Anglès
Document:	Article ; recerca ; Versió acceptada per publicar
Matèria:	Chlorinated aliphatic hydrocarbons ; Groundwater contamination ; Biostimulation ; In situ chemical reduction ; Dehalococcoides ; Dehalogenimonas
Publicat a:	Science of the total environment, Vol. 935 (July 2024) , art. 173093, ISSN 1879-1026

DOI: 10.1016/j.scitotenv.2024.173093

Disponible a partir de: 2026-07-31 Postprint

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