Infiltration of secondary treated wastewater into an oxic aquifer: Hydrochemical insights from a large-scale sand tank experiment.

Autor: Horovitz M; Hydraulics and Environment Department, Laboratório Nacional de Engenharia Civil - LNEC, Avenida do Brasil 101, Lisbon 1700-066, Portugal; Institute of Applied Geosciences, Technische Universität Darmstadt, Schnittspahnstraße 9, Darmstadt 64287, Germany. Electronic address: mhorovitz@lnec.pt., Muñoz-Vega E; Institute of Applied Geosciences, Technische Universität Darmstadt, Schnittspahnstraße 9, Darmstadt 64287, Germany., Knöller K; Institute of Applied Geosciences, Technische Universität Darmstadt, Schnittspahnstraße 9, Darmstadt 64287, Germany; Department of Catchment Hydrology, Helmholtz Center for Environmental Research - UFZ, Theodor-Lieser-Straße 4, Halle (Salle) 06120, Germany., Leitão TE; Hydraulics and Environment Department, Laboratório Nacional de Engenharia Civil - LNEC, Avenida do Brasil 101, Lisbon 1700-066, Portugal., Schüth C; Institute of Applied Geosciences, Technische Universität Darmstadt, Schnittspahnstraße 9, Darmstadt 64287, Germany; Water Resources Management Division, IWW Water Centre, Moritzstraße 26, Mülheim an der Ruhr 45476, Germany., Schulz S; Institute of Applied Geosciences, Technische Universität Darmstadt, Schnittspahnstraße 9, Darmstadt 64287, Germany.
Jazyk: angličtina
Zdroj: Water research [Water Res] 2024 Dec 01; Vol. 267, pp. 122542. Date of Electronic Publication: 2024 Sep 27.
DOI: 10.1016/j.watres.2024.122542
Abstrakt: To mitigate groundwater level decline, managed aquifer recharge (MAR) with secondary treated wastewater (STWW) is increasingly considered and implemented. However, the effectiveness and potential risks of such systems need evaluation prior to implementation. In this study, we present a large-scale sand tank experiment to analyse processes related to the infiltration of real STWW through the vadose zone and subsequent mixing with oxic native groundwater. The varying composition of STWW from 15 infiltration cycles over six months of operation and the retention times were the main drivers of the observed processes, which were characterized by a wide range of analytical techniques such as in situ high-resolution oxidation-reduction potential (ORP) measurements, closed mass balances of solutes, characterization of dissolved organic carbon (DOC), stable nitrate isotopes analysis, as well as numerical flow and transport modelling. Depending on the composition and infiltration rates of the STWW, both nitrification and denitrification could be observed, even simultaneously at different locations in the tank. Furthermore, due to the variability of the real STWW we observed enhanced arsenic mobilisation during times of elevated phosphate concentrations of the infiltrating STWW. Additionally, uranium was mobilised in our experimental system via carbonate mineral dissolution caused by the infiltrating STWW which was undersaturated of calcite for all infiltration cycles. Overall, our results showed the importance of conducting studies with waters of complex matrix, such as real STWW, and considering mixing with groundwater to assess the full range of possible processes encountered at MAR field sites.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2024. Published by Elsevier Ltd.)
Databáze: MEDLINE
Externí odkaz: