Department Process Engineering

Process Engineering

The research focus of the Process Engineering Department (ENG) ranges from current and future wastewater and drinking water treatment problems, as well as water pollution control and resource reuse. Our long-term goal is to develop sustainable concepts of the water and nutrient cycle in residential areas.

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News

Toolbox for planning decentralised sanitation systems

The toolbox contains three sets of individual sheets that help with planning decentralised wastewater solutions – from defining goals and selecting a strategy to providing an overview of possible technologies. (Photo: Eawag, Peter Penicka)
November 18, 2025 –

An Eawag toolbox provides an overview of technologies for decentralised sanitation systems, their respective advantages and examples of built systems.

An Eawag toolbox provides an overview of technologies for decentralised sanitation systems, their respective advantages and examples of built systems.
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10 years of Eawag Sensorlab

A series of temperature sensors with radio transmission is ready for a general overhaul, as operating conditions in the mountains or in sewer systems can be harsh. (Andri Bryner, Eawag)
November 11, 2025 –

Sensorlab is celebrating. It keeps water research at the cutting edge with new measurement and automation solutions, data transmission and management.

Sensorlab is celebrating. It keeps water research at the cutting edge with new measurement and automation solutions, data transmission and management.
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Early detection for wastewater treatment plants

Treated wastewater can be continuously monitored using online monitoring with organisms. The data obtained in this way makes it possible to respond quickly to acute stress. (Photo: Ecotox Centre)
June 17, 2025 –

Researchers from the Ecotox Centre, Eawag and the University of Applied Sciences Northwestern Switzerland have tested combined biological and chemical online monitoring as an early warning system at a municipal wastewater...

Researchers from the Ecotox Centre, Eawag and the University of Applied Sciences Northwestern Switzerland have tested combined biological and chemical online monitoring as an early warning system at a municipal wastewater treatment plant. The system is able to detect peak loads of micropollutants in treated wastewater and identify toxic pollutants in real time. In this way, it can contribute to improving wastewater management.
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Water Hub: new movie!

Publications

Hamilton, K. A., Quon, H., Ashbolt, N. J., Gurian, P. L., Reynaert, E., Haas, C. N., … Wilson, A. M. (2026). Making waves: Moving beyond the 1 in 10,000 benchmark in quantitative microbial risk assessment (QMRA) through evidence-informed risk approaches and systems decision-making. Water Research, 289, 124903 (8 pp.). doi:10.1016/j.watres.2025.124903, Institutional Repository

Public health decision-making for the management of infectious diseases quantifies human risks, typically segmented by vulnerability groupings to evaluate risk management interventions. While many paradigms are available for evaluating risks and their tradeoffs, relatively few are used in practice. Many sectors such as water reuse rely on benchmark approaches for risk, such as 1 in 10,000 infections per person per year. As risk-risk tradeoffs are increasingly considered in quantitative microbial risk assessments (QMRA), there is a need to broaden acceptability criteria beyond such approaches to consider holistic aspects of decision-making such as broader sustainability and cost impacts, and fairness. Evidence-based benchmarks can be incorporated into a systems approach to risk management by providing a more integrated alternative to strict policy-recommended one-size-fits-all targets. Potential research gaps for both existing and forward-looking metrics of acceptable microbial risk and alternative approaches are identified, with water reuse as a focus area.
Pan, R., Zheng, Z. X., He, H., Zhang, T. Y., Zeng, C., Fu, Q., … Xu, B. (2026). Selective elimination of aniline contaminants induced by semiquinone radicals during peracetic acid oxidation of dihydroxybenzenes. Water Research, 289, 124840 (11 pp.). doi:10.1016/j.watres.2025.124840, Institutional Repository

This study investigated the reaction mechanisms of peracetic acid (PAA) with dihydroxybenzenes (HBs) to generate reactive species for degradation of micropollutants containing aniline(-like) structures, including 7 sulfonamide antibiotics, 17 (non-)substituted anilines, and 3 nucleobases. Three of the studied HBs significantly enhanced aniline degradation kinetics by PAA, with degrees following the order of catechol (CA) > protocatechuic acid > hydroquinone. The PAA/CA process at the optimal condition (initial pH 7, 100-μM PAA, 50-μM CA) achieved 90% removal efficiency of sulfadiazine in 40 min with minimal interference by anions (Cl−, SO42−, and HCO3−), humic acid, and real (waste)waters. Results of scavenging experiments, electron paramagnetic resonance analyses, and transformation product profiles collectively support that semiquinone radical (SQ•−), originated from oxidation of CA by PAA, dominated aniline degradation through nucleophilic addition toward the amino groups on aniline moieties, resulting in formation of C−N coupling products and detoxication of anilines. The critical role of o-SQ•− is further highlighted by the linear correlation between ln-scale observed pseudo-first-order rate constant (kobs) with the Hammett constant (σ) for sulfonamides and (non-)substituted anilines (r = -0.77). Besides, a non-radical pathway driven by singlet oxygen (1O2) made important while non-dominant contribution to aniline degradation. Overall, this work sheds light on reactive species formation during oxidation of phenolic compounds by PAA and proposes a novel strategy for selective elimination of aniline-containing contaminants in wastewater treatment.
Parniske, J., Froemelt, A., & Morck, T. (2026). Modelling competitive adsorption of organic micropollutants onto granular activated carbon in fixed-bed adsorbers for advanced wastewater treatment. Water Research, 288, 124631 (13 pp.). doi:10.1016/j.watres.2025.124631, Institutional Repository

Adsorption of potentially toxic and persistent organic micropollutants (OMP) in granular activated carbon (GAC) fixed-bed adsorbers has become increasingly established as an advanced wastewater treatment process in recent years. To gain a deeper understanding of relevant removal mechanisms and operating conditions, this work investigates a multisolute model approach for the filter breakthrough curve (BTC) prediction of OMP and dissolved organic carbon based on the ideal adsorbed solution theory in combination with the tracer model for competitive adsorption and the linear driving force model for surface diffusion. The model was calibrated with equilibrium and kinetic batch experiments and validated based on operational data from full-scale and pilot-scale GAC filtration. Model predictions proved well for OMP removal dominated by adsorption mechanisms (benzotriazole, carbamazepine), but revealed the need to include biodegradation processes particularly for diclofenac and to further investigate the role of short empty bed contact times and desorption processes for the model performance. Implementation of filter backwashing showed an additional effect on the breakthrough curve behaviour and significantly improved model predictions for the full-scale GAC adsorber.
Appiah-Twum, H., Van Winckel, T., Santolin, J., De Paepe, J., Hellweg, S., Larsen, T. A., … Spiller, M. (2025). Environmental impact of integrating decentralized urine treatment in the urban wastewater management system: a comparative life cycle assessment. Water Research, 282, 123630 (14 pp.). doi:10.1016/j.watres.2025.123630, Institutional Repository

As municipal wastewater treatment regulations become more stringent, integrating source-separated urine treatment into centralized urban wastewater management offers a ‘hybrid’ solution. However, it is not clear how the environmental impacts of such hybrid systems compare to highly efficient centralized wastewater treatment plants (WWTPs) with low N2O emissions and electricity use. In this study, a consequential life cycle assessment was used to compare the environmental impact of three urine separation hybrid wastewater treatment systems – which combine decentralized urine treatment with a highly efficient central WWTP– to a centralized WWTP treating mixed wastewater (baseline). The studied urine treatment systems include partial nitrification & distillation, struvite precipitation & stripping/scrubbing, and partial nitritation/anammox. Additionally, the environmental impact of urine pre-treatment by calcium hydroxide and electrochemical alkalinization methods on the partial nitrification & distillation system was evaluated. The results show that all hybrid scenarios have a lower environmental impact in the freshwater ecotoxicity, marine toxicity, freshwater eutrophication, and marine eutrophication categories compared to the baseline. However, all hybrid scenarios resulted in higher impacts on global warming compared to the baseline, with direct N2O emissions being a key variable. Additionally, it was identified that urine alkalinization increased the environmental impact of the treatment system in 7 out of the 10 impact categories. A Pareto frontier analysis was developed to guide decision makers on where hybrid solutions could be used as a strategy to reduce the global warming impacts of conventional WWTPs. Using N2O-N emission factors of 75 WWTPs, 87 % of centralized WWTPs had a lower global warming impact compared to partial nitrification & distillation, and 91 % compared to partial nitritation/anammox hybrid solutions. However, at electricity demands of 1 kWh/PE/day and 1.5 kWh/PE/day at the central WWTP, both hybrid solutions showed lower global warming impact than all the studied WWTPs. The study highlights the potential of hybrid wastewater treatment solutions as a strategy to reduce global warming impacts in WWTPs with high N2O emissions and electricity use as well as a means to reduce marine eutrophication (i.e. nitrogen pollution).

Events

20.01.​2026,
26.02.​2026,

Research Projects

Is a space research program, aiming to develop a bioregenerative life support system for long-term space missions and space habitations for example on Mars.

Melissa «Micro Ecological Life Support System Alternative»
NEST building
Sustainable urban water and wastewater management applied and implemented in the modular NEST building.

WaterHub at NEST
Modelling of aerobic granular sludge (AGS) reactors

Eawag Aerobic Granular Sludge (AGS) Model
Many WWTPs are reaching their maximum treatment and clarification capacities, and solutions must be found to upgrade those existing plants.

Micro-sieving of municipal wastewater
Opportunities and risks of reusing treated wastewater in Switzerland

Water Reuse Switzerland
The Swiss Federal Council set the ambitious goal to reach net-zero greenhouse gas emissions by 2050.

SCENE - Reducing N2O emissions from wastewater treatment
Dynamic of greenhouse gas emissions in nutrient removing wastewater treatment plants

N2O - Dynamic of greenhouse gas emissions
Systematic investigation of hybrid model approaches for the prediction of nitrous oxide emissions in biological wastewater treatment

MAD4WW

More Research Projects