Adequate supply of freshwater is an immense growing problem worldwide due to increasing demands and pollution. An increasing problem is the occurrence of organic micro-pollutants (OMPs) in surface and groundwater. OMPs are organic chemicals with complex and highly variable structures that occur at trace concentrations (μg–ng/L) and often have unknown eco-toxicological and/or human health effects. OMPs include pesticide residues, pharmaceuticals, personal care products, (synthetic) hormones, and others. They enter surface and ground waters through diffuse and point sources such the use of pesticides, manure, municipal and industrial wastewater treatment plants. Till recently, target OMPs mainly were pesticide residues. However, several other OMP chemicals were recently added to the EU surface water watch-list emphasizing the importance of OMP pollution in water. Similarly, while current quality standards for OMPs in drinking water only relate to pesticide residues, drinking water companies are already monitoring other OMP groups in influent and finished drinking water.

Changes in regulations and consumer behavior are likely insufficient to fully control the complex OMP discharge routes. End of pipe removal of OMPs from wastewater and treatment of raw intake water for drinking water require so-called advanced water treatment (AWT). Current commercialized AWTs are physicochemical processes, such as membrane filtration (including nanofiltration (NF) and reverse osmosis (RO)), adsorption on activated carbon (AC) and advanced oxidation processes (AOP). They show satisfying removal efficacies, but are energy-intensive, use high amounts of chemicals, or result in toxic waste.

To improve sustainability, a technology combining retention and destruction of OMPs with a minimal input of energy and chemicals is required. SmartDetox is an FWO-funded project that aims at developing such technologies and assessing/optimizing its feasibility by combining technological developments with an in-depth understanding of the underlying processes.

The main challenges for the development of such technology are: (i) the extreme low concentrations at which the OMPs occur and that will impact degradation rates, (ii) their presence as complex mixtures and (iii) the possibility of creating toxic transformation products (TPs).To tackle these challenges, the main aim of this project is to develop a customized state-of-the-art membrane technology to concentrate the OMPs and to subsequently improve their destruction by biodegradation and/or plasma-based oxidative degradation (POD). POD will be used to treat effluents from municipal WWTPs while biodegradation will focus on groundwater treatment in drinking water treatment plants (DWTPs). To guide the optimization of these technologies, innovative analytical techniques will be developed.

The Membrane Technology Group of KU Leuven (prof. Ivo Vankelecom) will research and develop innovative membranes for OMP enrichment.  Nanofiltration membranes typically retain compounds with a molecular weight between 200 and 1000 Da, based on a combination of steric exclusion and charge repulsion, while tighter RO-membranes retain all solutes. To adequately remove typical OMPs (150-300 Da), very dense membranes are thus required. Obviously, these membranes will also retain (inorganic) ions. Ideal membranes should retain OMPs and allow passage of salts and water at low pressure. Such membranes are currently not available on the market but preliminary academic research exists, i.e. using so-called ‘mosaic membranes’, showing patches of negatively charged polymers in a matrix of a positively charged polymer or vice versa.  Water can pass through both regions, while these charged regions simultaneously are dense enough to retain organics. If you would like more information about this project please contact Bart van Duffel (Innovation mgr MTG).