Abteilung Verfahrenstechnik

Verfahrenstechnik

Unsere Forschungsgruppen beschäftigen sich aus der ingenieurtechnischen Perspektive mit Problemen der Abwasserreinigung und Trinkwasseraufbereitung sowie dem Schutz der Wasserressourcen. Unser langfristiges Ziel ist es, nachhaltige Konzepte für Wasser- und Nährstoffkreisläufe in Siedlungen zu entwickeln.

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News

Die Abwasserreinigung auf Berghütten fairer beurteilen

Die alternative Methode zur Beurteilung der Reinigungsleistung von Kleinkläranlagen von Berghütten mittels Kalium als Tracer wird derzeit durch Messungen in der Chamanna Cluozza und weiteren Berghütten validiert (Foto: Adobe Stock).
12. Februar 2025 –

Die Bedingungen in Berghütten machen es oft schwierig und unverhältnismässig, die Vorgaben für die Abwasserreinigung zu erreichen. Ein neuer Ansatz zur Beurteilung der Reinigungsleistung könnte das ändern.

Die Bedingungen in Berghütten machen es oft schwierig und unverhältnismässig, die Vorgaben für die Abwasserreinigung zu erreichen. Ein neuer Ansatz zur Beurteilung der Reinigungsleistung könnte das ändern.
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Otto-Jaag-Gewässerschutzpreis 2024 für Valentin Faust

ETH-Rektor Günther Dissertori überreicht Valentin Faust den Otto-Jaag-Gewässerschutzpreis 2024 (Foto: ETH, Alessandro Della Bella).
18. November 2024 –

Für seine Dissertation wurde der Umweltingenieur Valentin Faust am ETH-Tag vom 16. November 2024 mit dem Otto-Jaag-Gewässerschutzpreis ausgezeichnet. Seine Arbeit liefert wichtige Erkenntnisse für die Herstellung von Dünger aus...

Für seine Dissertation wurde der Umweltingenieur Valentin Faust am ETH-Tag vom 16. November 2024 mit dem Otto-Jaag-Gewässerschutzpreis ausgezeichnet. Seine Arbeit liefert wichtige Erkenntnisse für die Herstellung von Dünger aus menschlichem Urin.
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Trockene Sommer: Wiederverwendung von gereinigtem Abwasser könnte helfen

In einigen Nachbarländern der Schweiz dürfen seit 2023 Landwirtschaftsflächen mit gereinigtem, kommunalem Abwasser bewässert werden (Foto: Adobe Stock).
17. Oktober 2024 –

Mit dem Klimawandel nehmen heisse und trockene Sommer zu, in denen auch in der Schweiz regional das Wasser knapp wird. Die Wiederverwendung von gereinigtem Abwasser könnte zur Lösung dieses Problems beitragen. Das hat ein Team der...

Mit dem Klimawandel nehmen heisse und trockene Sommer zu, in denen auch in der Schweiz regional das Wasser knapp wird. Die Wiederverwendung von gereinigtem Abwasser könnte zur Lösung dieses Problems beitragen. Das hat ein Team der Eawag im Auftrag des BAFU und einiger Kantone gezeigt. Die Forschenden erläutern auch, was noch getan werden muss, damit aus der Option Realität wird.  
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Water Hub: Neuer Film aus dem NEST

Publikationen

Britschgi, L., Wei, S., Proesl, A., Morgenroth, E., & Derlon, N. (2025). The critical role of flocs in nitrification in full-scale aerobic granular sludge-based WWTP. Water Research, 274, 123021 (13 pp.). doi:10.1016/j.watres.2024.123021, Institutional Repository

Aerobic granular sludge (AGS) is usually considered to be a biofilm system consisting of granules only, although practical experience suggests that flocs and granules of various sizes co-exist. This study thus focused on understanding the contribution of flocs and granules of various sizes to nitrification in a full-scale AGS-based wastewater treatment plant (WWTP) operated as a sequencing batch reactor (SBR). The size distribution in terms of total suspended solids (TSS) and the distribution of the nitrifying communities and activities were monitored over 14 months. Our results indicate that AGS is a hybrid system in which flocs (<0.25 mm) play a critical role in nitrification. AGS consisted of 36 % flocs and 50 % large granules (>2 mm) at a TSS concentration of 4.7 ± 0.7 gTSS L-1. The growth of ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB) in large granules was limited due to the high mass transfer limitation in biofilm and the high solids retention time (SRT) of flocs, where favorable conditions for the growth of nitrifiers were maintained during the warm season. The specific activities of the small aggregates (<1 mm) were 5 to 15 times higher than those of large granules. As a result, flocs contributed >50 % to nitrification during the warm season, whereas granules >1 mm contributed <20 %. Such predominance of flocs in nitrification became problematic in the cold season when the minimum SRT of NOB increased to values similar to the floc SRT, resulting in 79 % loss of the NOB. Consequently, NOB activities dropped, and elevated effluent nitrite concentrations of several mgN L-1 were monitored. We suggest operating AGS systems similarly to hybrid systems in order to promote the enrichment of NOB in the granules by controlling the floc SRT at low values smaller than the minimum SRT of NOB throughout the year.
Froemelt, A., Zueger, L., von Kaenel, L., Braun, D., & Gruber, W. (2025). Pattern recognition of operational states leading to N2O-emissions in full-scale biological wastewater treatment. Water Research X, 29, 100336 (12 pp.). doi:10.1016/j.wroa.2025.100336, Institutional Repository

Given the urgency to reduce greenhouse gas emissions in the whole economy, the abatement of nitrous oxide (N2O) built-up in biological wastewater treatment would be an important contribution of the waste sector. However, the complexity of N2O-formation in activated sludge and non-linear dynamics of operating factors pose difficulties to apply effective measures for a specific high-emission situation in a full-scale context. Facing such complex interactions and unknown relationships, data mining can provide useful support to analyze full-scale datasets. Therefore, the goal of this article is to investigate a data-driven method to understand high-emission patterns and their origins to provide a basis for the development of N2O-mitigation measures. We applied unsupervised artificial neural networks (self-organizing maps) and subsequent clustering to a 3-year, high-resolution dataset to identify and characterize operational states and to analyze the transitions among them. In the case study, hampered denitrification, anaerobic digestion supernatant addition, and indications of snowmelt were found among problematic situations. The transition analysis showed the importance of contextualizing a high-emission pattern as it can emerge from different origins, having implications when developing mitigation measures. Apart from analyzing the shift of operational states, a key advantage of the proposed methodology is the consideration of the combined effect of variables in specific situations. This renders it an effective tool to understand operational patterns. It can further be used to inform experiments by formulating hypotheses and prioritizing variables combinations; providing finally insights towards the development of situation-specific strategies for a low-N2O-operation of full-scale plants.
Furrer, V., Froemelt, A., Singer, H., & Ort, C. (2025). Source-specific dynamics of organic micropollutants in combined sewer overflows. Water Research, 279, 123416 (9 pp.). doi:10.1016/j.watres.2025.123416, Institutional Repository

Combined sewer overflows (CSOs) discharge organic micropollutants (MPs) into open water bodies, posing potential environmental threats. Knowledge of the numbers, sources, and dynamics of MPs during CSOs is scarce but crucial for assessing their impact and developing mitigation strategies. To shed light on the dynamics of dissolved organic MPs in CSOs, we conducted high-temporal-resolution sampling (10 min composite samples) followed by liquid chromatography high-resolution mass spectrometry analysis, both target (60 substances) and nontarget, at two CSO sites in a small [17 hectares reduced (hared)] and a large (368 hared) catchment for over 10 events each. We observe similar patterns among indoor substances in the large catchment and among tire-associated compounds in both catchments, indicating source-specific behavior. Due to high and diverse concentration variability, no temporal correlations were found among indoor substances in the small catchment or among pesticides in either catchment. A random forest classifier was applied to assign nontarget time series to indoor and road sources in the large catchment. The results indicate that CSOs discharge several thousand substances from indoor sources, followed by a few hundred from outdoor sources with continuous leaching. These high numbers substantially surpass the scope of traditional target lists and underscore the importance of broad-spectrum screening methods when assessing MP contamination.
Hu, Y., Morgenroth, E., & Jacquin, C. (2025). Online monitoring of greywater reuse system using excitation-emission matrix (EEM) and K-PARAFACs. Water Research, 268, 122604 (13 pp.). doi:10.1016/j.watres.2024.122604, Institutional Repository

A currently increasing interest in water reuse is met with the concern about water quality. Excitation-emission matrix (EEM) measurements, which are widely implemented in laboratory analysis, emerge as a promising tool for characterizing both microbial and chemical water qualities in the online monitoring of water reuse systems. However, the robustness of EEM measurements has been rarely validated in actual online monitoring campaigns where predictions are made for new samples independent of those used to establish EEM analysis models, including the popular parallel factor analysis (PARAFAC). In this study, two strategies of conducting PARAFAC were examined for the online monitoring of a greywater reuse system using two EEM datasets from two monitoring periods for model establishment and model testing respectively. With the first strategy that is commonly used in laboratory analyses, an entire EEM datasets from one period was used to establish one PARAFAC model, and the maximum fluorescence intensity (Fmax) of a PARAFAC component was used to predict total cell count (TCC) in another period. However, under the disturbance of dissolved organic matter (DOM) fluorescence in the background, Fmax gave unreliable predictions in model testing. To address this problem, a second and novel strategy was proposed using an EEM clustering and PARAFAC component shift mining technique. This unsupervised algorithm, named K-PARAFACs, automatically groups EEMs into K clusters and on each cluster establishes a cluster-specific PARAFAC model with distinct component shapes. With this method, multiple PARAFAC models were established on one EEM dataset, with each model representing samples with certain TCC ranges and DOM compositions. In model testing, these cluster-specific PARAFAC models served as EEM classifiers. A new sample was not characterized by Fmax but by the cluster-specific model that best fitted the EEM signal of the sample with the least numerical error. The proposed strategy demonstrates its robustness by successfully predicting the TCC trend in test datasets. Our findings suggest that K-PARAFACs is a promising tool that enables robust qualitative monitoring of water reuse systems with background DOM variability.

Veranstaltungen

24.06.​2025,
9:00 Uhr
Lausanne
Elimination poussée de l'azote des eaux usées municipales

Cours d’approfondissement PEAK-VSA V60/25

04.12.​2025,
9:00 Uhr
Eawag Dübendorf
Emissionen von Reifenpartikeln und Auswirkungen auf die Umwelt

PEAK-Basiskurs B36/25

Forschungsprojekte

Ist ein Raumfahrtforschungs- programm, das die Entwicklung eines bioregenerativen Lebenserhaltungssystems für langfristige Raumfahrtmissionen und Weltraumwohnungen zum Beispiel auf dem Mars zum Ziel hat

Melissa «Micro Ecological Life Support System Alternative»
NEST building
Nachhaltiges urbanes Wasser- und Abwassermanagement angewandt und umgesetzt im modularen NEST-Gebäude.

WaterHub im NEST
Mathematische Modellierung aerober granulierter Belebtschlamm (AGS) - Reaktoren

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
Der Schweizer Bundesrat hat sich das ehrgeizige Ziel gesetzt, bis 2050 die nationale Treibhausgasbilanz auszugleichen und somit auf "Netto Null" zu bringen.

SCENE - Reduktion von Treibhausgasemissionen aus der Abwasserbehandlung
Dynamik der Lachgasemissionen bei nährstoffeliminierender Abwasserreinigung

N2O - Dynamik der Lachgasemissionen
Systematische Untersuchung von hybriden Modellansätzen zur Vorhersage von Lach-gasemissionen in der biologischen Abwasserreinigung

MAD4WW

Weitere Forschungsprojekte