Compound-specific isotopic analysis (CSIA) and geochemical modeling were applied to evaluate the effectiveness of an 800 m-long sequential in situ bioremediation (ISB) system in Northern Italy. The system was created for the clean-up of a polluted aquifer affected by chloroethenes. A hydraulically upgradient anaerobic (AN)-biobarrier-stimulated reductive dichlorination (RD) of higher chloroethenes (PCE, TCE) and a downgradient aerobic (AE)-biobarrier-stimulated oxidation (OX) of lower chloroethenes (DCE, VC) were proposed. Carbon CSIA and concentration data were collected for PCE, TCE, cis-DCE and VC and interpreted using a reactive transport model that was able to simulate isotopic fractionation. The analysis suggested that the combination of CSIA and modeling was critical to evaluate the efficiency of sequential ISBs for the remediation of chloroethenes. It was found that the sequential ISB could reduce the PCE, TCE and cis-DCE concentrations by >99% and VC concentrations by >84% along the flow path. First-order RD degradation rate constants (kRD) increased by 30 times (from kRD = 0.2–0.3 y−1 up to kRD = 6.5 y−1) downgradient of the AN barrier. For cis-DCE and VC, the AE barrier had a fundamental role to enhance OX. First-order OX degradation rate constants (kOX) ranged between kOX = 0.7–155 y−1 for cis-DCE and kOX  = 1.7–12.6 y−1 for VC.

Assessing a large-scale sequential in situ chloroethene bioremediation system using Compound-Specific Isotope Analysis (CSIA) and geochemical modeling / G. Casiraghi, D. Pedretti, G.P. Beretta, M. Masetti, S. Varisco. - In: POLLUTANTS. - ISSN 2673-4672. - 2:4(2022 Nov 11), pp. 462-485. [10.3390/pollutants2040031]

Assessing a large-scale sequential in situ chloroethene bioremediation system using Compound-Specific Isotope Analysis (CSIA) and geochemical modeling

G. Casiraghi
Primo
;
D. Pedretti
Secondo
;
G.P. Beretta;M. Masetti
Penultimo
;
S. Varisco
Ultimo
2022

Abstract

Compound-specific isotopic analysis (CSIA) and geochemical modeling were applied to evaluate the effectiveness of an 800 m-long sequential in situ bioremediation (ISB) system in Northern Italy. The system was created for the clean-up of a polluted aquifer affected by chloroethenes. A hydraulically upgradient anaerobic (AN)-biobarrier-stimulated reductive dichlorination (RD) of higher chloroethenes (PCE, TCE) and a downgradient aerobic (AE)-biobarrier-stimulated oxidation (OX) of lower chloroethenes (DCE, VC) were proposed. Carbon CSIA and concentration data were collected for PCE, TCE, cis-DCE and VC and interpreted using a reactive transport model that was able to simulate isotopic fractionation. The analysis suggested that the combination of CSIA and modeling was critical to evaluate the efficiency of sequential ISBs for the remediation of chloroethenes. It was found that the sequential ISB could reduce the PCE, TCE and cis-DCE concentrations by >99% and VC concentrations by >84% along the flow path. First-order RD degradation rate constants (kRD) increased by 30 times (from kRD = 0.2–0.3 y−1 up to kRD = 6.5 y−1) downgradient of the AN barrier. For cis-DCE and VC, the AE barrier had a fundamental role to enhance OX. First-order OX degradation rate constants (kOX) ranged between kOX = 0.7–155 y−1 for cis-DCE and kOX  = 1.7–12.6 y−1 for VC.
chloroethenes; enhanced bioremediation; anaerobic organohalide respiration; aerobic oxidative biodegradation; landfill; compound-specific stable isotope analysis; reactive transport model; PHREEQC
Settore GEO/05 - Geologia Applicata
Article (author)
File in questo prodotto:
File Dimensione Formato  
pollutants-02-00031-v3.pdf

accesso aperto

Tipologia: Publisher's version/PDF
Dimensione 2.72 MB
Formato Adobe PDF
2.72 MB Adobe PDF Visualizza/Apri
Pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/945930
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus ND
  • ???jsp.display-item.citation.isi??? ND
social impact