Advanced Water Treatment

The research group deals with the question how to manage the anthropogenic water cycle and material cycles to supply water in sufficient quality and quantity for a growing world population in view of an accelerating climate change and attributed challenges. In the research projects we develop approaches that reflect closed water cycles contrasting the traditionally linear “take-make-waste” paradigm of centralized water supply and waste water discharge. Hence, advanced water treatment may be employed on either side, wastewater treatment or drinking water purification. This paradigm change is also propelled by current regulative initiatives, e.g. revision of EU Urban Wastewater Treatment Directive and EU regulation for agricultural water reuse. For advanced water treatment, combined or hybrid treatment processes are of paramount importance to remove trace organic chemicals at ng/L to µg/L level (e.g. pharmaceuticals, personal care products, industrial chemicals), and pathogenic microorganisms including antimicrobial resistances. Hybrid treatment processes relying on different physical, chemical and biological removal mechanisms offer the multiple barriers also against contaminants of emerging concern (CEC), e.g. persistent, mobile and toxic (PMT) substances or PFAS, and even unknown contaminants. In particular, we investigate hybrid treatment processes that combine separation and conversion, e.g. adsorption – biotransformation or membrane filtration – advanced oxidation or adsorption – advanced oxidation, or that combine different separation principles, e.g. activated carbon adsorption – ultrafiltration.

Adsorption:

• Improve the removal performance and process efficiency by adsorbent selection (e.g. activated carbons, zeolites, metal-organic frameworks), adsorber design and operation, and adsorbent regeneration/reactivation including in-situ and on-site regeneration
• Understand and model the transport and removal mechanisms of contaminants in complex water matrices leading to competitive adsorption

Membrane filtration:

• Mitigate and control fouling, e.g. organic fouling or biofouling, by pretreatment measures, e.g. UV irradiation, and feed channel and/or feed spacer design
• Improve the rejection of small, difficult-to-treat contaminants (e.g. antimicrobial resistance genes, pathogenic viruses for ultrafiltration or uncharged, low molecular-weight organic compounds for nanofiltration/reverse osmosis) by suitable process operational conditions and membrane selection

Oxidation and advanced oxidation:

• Evaluate the reactions of oxidants (e.g. ozone and radicals) with target contaminants (e.g. CECs or pathogens or antibiotic resistances) in water and wastewater matrices and optimize their process efficiency
• Develop and scale up emerging technologies, e.g. UV/chlorine, UV/persulfate and BDD electrodes

Natural and biological treatment processes, such as riverbank filtration, soil-aquifer treatment or biologically-active filters:

• Determine the key factors for the removal of CECs in natural systems and exploit them to improve process control
• Develop novel concepts for enhanced removal of CECs, e.g. sequential managed aquifer recharge technology (SMART)