direkt zum Inhalt springen

direkt zum Hauptnavigationsmenü

Sie sind hier

TU Berlin

Inhalt des Dokuments

N6 Retention of chemical compounds in hyporheic reactors of urban freshwater systems

Doctoral student: Jonas Schaper

Supervisors: Dr. Jörg Lewandowski, Prof. Dr. Gunnar Nützmann, Dr. Anke Putschew

Introduction

Wastewater treatment plant (WWTP) derived trace organic compounds (TrOCs) are frequently detected in urban surface waters and groundwater. In WWTP effluent receiving streams, TrOCs may not only impair ecosystem functioning, but also pose risks for drinking water production downstream. Hyporheic zones (HZs) are considered to constitute a major sink for WWTP derived TrOCs in rivers, potentially mitigating adverse effects of TrOCs within urban water cycles. However, the biogeochemical factors as well as the hydrological controls that govern both, the in-situ fate of TrOCs in the hyporheic zone, as well as the relative contribution of the hyporheic zone attenuation to whole-stream TrOCs attenuation are largely unknown.

Aims

The aims of this doctoral thesis therefore are:  i) to determine in-situ, first-order removal rate constants for a variety of WWTP derived TrOCs under various hydrological and biogeochemical conditions ii) broaden our conceptual understanding of the hydrological controls on the fate of TrOCs in the HZ applying the concept of exposure times and Damkoehler numbers and iii) to determine the hydrological factors that govern the relative contribution of the HZ to overall whole-stream TrOCs attenuation.

Methods

We use high-resolution passive and active in-situ porewater sampling to resolve the spatiotemporal distribution of biogeochemical parameters and TrOCs within the HZ. Simultaneously, hydrological methods are applied to determine hyporheic flow velocities (heat-pulse sensing, temperature depth profiles, push-pull tracer experiments). Subsequently, information on subsurface flow velocities and compound concentrations are used to calculate removal rate constants via simple reactive transport modeling.

Preliminary results

Preliminary results highlight the importance of redox conditions for the removal of many TrOCs within the HZ. While most investigated TrOC are well removed under oxic/suboxic conditions, removal rate constants are indistinguishable different from zero when redox conditions become anoxic.

Lupe
Lupe

Collaborations

This project is being conducted in collaboration with UWI Project N7, Flinders University in Adelaide (AUS) and Stockholm University (SWE).

Initial project plan

Zusatzinformationen / Extras

Quick Access:

Schnellnavigation zur Seite über Nummerneingabe

Auxiliary Functions