WP2 – Strategies for mitigation of CECs during indirect potable reuse practices

WP leader: Prof. Jörg E. Drewes (TUM)

WP2 will focus on INPR practices that hold particular promise to augment water supplies in Europe while saving freshwater resources. These practices include groundwater recharge and streamflow augmentation, which are already practiced at some locations in Southern and Central Europe. Management strategies developed during WP2 include secondary and advanced tertiary treatment prior to release into the environmental buffer (i.e., groundwater or receiving surface water) and at the drinking water plant.


  • Establishment of novel treatment combinations (biological nutrient removal, chemical oxidation, modified biological filters, soil-based treatment) for indirect potable reuse (INPR) practices
  • Evaluation of treatment process efficiency by monitoring removal of CECs (contaminants of emerging concern) as well as elimination of FIBs, pathogens and antibiotic-resistant bacteria/genes in controlled studies at pilot-scale
  • Monitoring to validate CEC removal at two full-scale water reclamation facilities in Spain and one advanced wastewater treatment plant in Germany practicing INPR
  • Designing new sampling and preservation strategies for process evaluation
  • Determination of CEC mass balances based on TP formation and degradation kinetics

Task 2.1 Pilot-scale studies for viable process combinations leading to INPR
Within Task 2.1, novel treatment combinations to be included in INPR schemes will be investigated using existing pilot-scale facilities at TUM. These processes will include ozone, advanced oxidation processes (AOP, UV/H2O2), enhanced biological filtration and soil-aquifer treatment (SAT) or irrigation and be compared to a reference treatment train using only biological nutrient removal processes followed by disinfection (i.e., chlorine or chlorine dioxide). Removal rate constants for chemical and microbial contaminants will be derived, distinguishing between the biotic and abiotic transformations or inactivation of CECs, FIBs, pathogens and antimicrobial-resistant bacteria/genes for each process. These rate constants derived under well-defined conditions will be fed into treatment process and contaminant transport models developed in WP3.

Task 2.2 Development of appropriate monitoring strategies including sampling and preservation procedures
Within Task 2.2, a comprehensive sampling and preservation concept will be developed to evaluate the removal of CECs, the inactivation of microbial contaminants, the removal of antibiotic-resistant bacteria/genes, and the reduction of ecotoxicological effects by various INPR processes. This concept will consider i) influent variations of CECs and pathogens, ii) analytical uncertainties, iii) inherent process variations (e.g., temperature, hydraulic retention times), iv) the biodegradability of CECs as well as v) potential losses and biotransformation during sample shipment.

Task 2.3 Formation of TPs and pathway elucidation
In Task 2.3, degradation kinetics and transformation pathways of selected CECs will be elucidated using lab-scale experiments. The principal biotic and abiotic TPs of selected CECs will be identified for chemical oxidation (e.g. ozonation) and for biological processes (e.g. biofiltration, SAT). The formation of toxic TPs and mass balances of CEC transformations will be used to evaluate the efficacy of processes studied at pilot- and full-scale.

Task 2.4 Full-scale studies for INPR
In Task 2.4, the performance of specific processes and process combinations as well as the general applicability of FRAME will be validated through monitoring campaigns at full-scale facilities in Spain and Germany. Focusing on critical control points, this will entail a profound assessment on how effectively CECs, TPs and pathogens are attenuated during various treatment strategies. If further minimization of any remaining risks associated with CECs or pathogens is desired for a given site, appropriate process optimization strategies will be developed.