Wastewater treatment plants (WWTPs) treat domestic and industrial wastewater, which is then discharged as effluent into surface water. Although the quality of effluent has significantly improved in recent years, emerging organic micro-pollutants (OMPs) such as pharmaceutical residues, pesticides, and PFAS compounds are attracting increasing attention.

Through the Interreg project "O3G," various partners in Flanders (Vlakwa, AM-Team, Aquafin, CAPTURE, University of Antwerp and Ghent University) and the Netherlands (Hogeschool Zeeland, PureBlue Water, and Waterschap de Dommel) aim to demonstrate that Ozonation (O3) combined with Granular Activated Carbon (GAC) can be implemented at WWTPs as an innovative, effective, and cost-efficient post-treatment technology that improves surface water quality in Flanders and the Netherlands.

Ozonation is a highly efficient technology for removing a wide range of organic micro-pollutants, but it has the drawback of potentially forming harmful by-products such as bromate and transformation products. A higher ozone dosage, necessary for extensive removal of OMPs, also increases the risk of forming these by-products. GAC filtration does not form these by-products, but frequent regeneration of the activated carbon is necessary, leading to high costs and a significant carbon footprint.

Therefore, this project investigates how these two technologies can be combined to achieve the highest possible OMP removal with minimal by-product formation, minimal GAC regeneration, and optimal energy and resource consumption.

The project includes tests on new full-scale installations at Aquafin in Aartselaar and at Waterschap De Dommel in Tilburg, among other activities.
More info can be found at: https://interregvlaned.eu/schone-waterlopen-door-o3g/over-ons

Ghent University is a scientific partner in the project and is primarily responsible for conducting laboratory-scale experiments to investigate the mechanisms and effectiveness of O3-GAC. Additionally, possibilities for digital online monitoring, especially based on UV-VIS measurements and the development of multi-criteria control strategies will be explored. Methods for analyzing recalcitrant OMPs will be developed, particularly for use in laboratory-scale experiments. Towards the end of the project, it will be assessed whether it is feasible to apply these analyses to pilot setups or full-scale installations. Finally, a hotspot analysis of WWTPs in Flanders, identifying which WWTPs prioritize implementing O3-GAC will be supported.