Subsurface passage as utilised during river bank filtration and artificial groundwater recharge has been proven to be an effective barrier for multiple substances present in surface waters during drinking water production. Additionally it is widely used as polishing step after wastewater treatment. However, there are limitations concerning the removal of DOC and specific trace organics. The project OXIRED aims at assessing possibilities to overcome these limitations by combining subsurface passage and oxidation processes (e.g. ozonation) as pre- or post-treatment.

In the first phase of the project (OXIRED-1), literature studies as well as laboratory and technical scale experiments were carried out in order to evaluate the theoretical benefit and limitations of such a system and identify knowledge gaps. From this recommendations for the implementation of a pilot were derived concerning set-up and hydraulic and hydrochemical background.

In the currently running 2nd phase of the project laboratory and technical scale experiments as well as pilot scale trials will be carried out (work package 1) in order to investigate the formation and degradation of possibly toxic oxidation by-products and to verify the findings from the first phase under more realistic conditions. In addition, different potential sites for the installation of a demonstration plant will be identified and characterized with regard to feasibility on the basis of available data (work package 2). In work package 3 first laboratory experiments on redox control in AR ponds will be carried out, accompanied by reactive transport modelling in order to optimize the design of infiltration ponds.