Modellierung von Grundwasserströmung und reaktivem Stofftransport im mit PFAS kontaminierten Aquifer Westliches Leibnitzer Feld, Steiermark und Ableitung von Sanierungsvarianten

Translated title of the contribution: Groundwater Flow and Reactive Transport Model of the PFAS Contaminated Aquifer ¿Westliches Leibnitzer Feld, Styria¿ and Derivation of Remediation Variants

Richard Moderegger

Research output: ThesisMaster's Thesis

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Abstract

This thesis is concerned with the PFAS contamination in the pore aquifer Western Leibnitzer Feld, Styria, which most likely originates from the styrian firefighting training site in Lebring - Sankt Margarethen. The focus lies on modeling the groundwater flow and PFAS transport in the affected area. An existing groundwater flow model of the area showed discrepancies between the calculated groundwater flow direction and the observed PFAS plume. Therefore, the existing groundwater flow model was evaluated with respect to identifying model parameters exhibiting the largest impact on the groundwater flow. Results show that especially leakage of the river Mur near Lebring as well as a possible anisotropy of hydraulic conductivity are heavily influencing the groundwater flow direction. After implementing geologically plausible adaptions, the match of groundwater flow direction and PFAS transport can be significantly improved resulting in only a slight increase in model error regarding hydraulic heads. Furthermore, the temporal boundary was expanded into the year 2023. Following that, the chemical fingerprint of the contamination was investigated. PFOS, PFHxS, PFPeA and PFHxA can be classified as main contaminants. While PFOS and PFHxS are detected all over the investigated plume, the occurrence of PFPeA and PFHxA is focused on the near-source area. Possible reasons are a higher adsorption of PFPeA and PFHxA reducing the transport velocity, or a later release of these contaminants. The reactive transport of the main contaminants was coupled to the groundwater flow and modeled for varying adsorption coefficients. The results allow the deduction of a linear correlation between the adsorption coefficients and the transport velocity of the PFAS for this specific site and independent of source concentration. Furthermore, the contaminant transport model qualitatively fits well with the observed PFAS distribution. Based on these results, some possible variants for remediation and safeguarding of the contamination were deducted and the range of costs described for selected methods. Using rough calculations and modeling, two possible groundwater remediation well arrangements and necessary extraction rates are presented. The results of this thesis thereby provide a valuable contribution to the development of a conceptual site model and aids in further remediation ambitions.
Translated title of the contributionGroundwater Flow and Reactive Transport Model of the PFAS Contaminated Aquifer ¿Westliches Leibnitzer Feld, Styria¿ and Derivation of Remediation Variants
Original languageGerman
QualificationDipl.-Ing.
Awarding Institution
  • Montanuniversität
Supervisors/Advisors
  • Sedlazeck, Klaus Philipp, Co-Supervisor (internal)
  • Misch, David, Co-Supervisor (internal)
  • Pomberger, Roland, Supervisor (internal)
Award date22 Mar 2024
DOIs
Publication statusPublished - 2024

Bibliographical note

no embargo

Keywords

  • PFAS
  • firefighting training site Lebring
  • AFFF
  • Leibnitzer Feld
  • groundwater flow model
  • contaminant transport model
  • site remediation
  • adsorption

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