Département Technologie des procédés

Technologie des procédés

Nos groupes de recherche se consacrent, sous l'angle de l'ingénierie technique, aux problèmes de l'épuration des eaux usées et du traitement de l'eau destinée à la consommation, ainsi qu'à la protection des ressources en eau. Notre objectif est de développer des concepts durables pour les cycles hydrologiques et des nutriments dans les communautés urbaines.

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News

Évaluer plus équitablement le traitement des eaux usées dans les refuges de montagne

La méthode alternative pour évaluer la performance d’épuration des petites stations dans les refuges de montagne avec le potassium comme traceur est en cours de validation à l’appui de mesures effectuées à la Chamanna Cluozza et dans d’autres refuges (Photo: Adobe Stock).
12 février 2025 –

Du fait des conditions dans les refuges de montagne, respecter les prescriptions en matière de traitement des eaux usées s’avère souvent difficile et demande des efforts disproportionnés. Une nouvelle approche d’évaluation de la...

Du fait des conditions dans les refuges de montagne, respecter les prescriptions en matière de traitement des eaux usées s’avère souvent difficile et demande des efforts disproportionnés. Une nouvelle approche d’évaluation de la performance d’épuration pourrait changer la donne.
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Le prix Otto Jaag pour la protection des eaux 2024 revient à Valentin Faust

Le recteur de l’EPF, Günther Dissertori, remet à Valentin Faust le prix Otto Jaag pour la protection des eaux (Photo: EPF, Alessandro Della Bella).
18 novembre 2024 –

Lors de la Journée de l’EPF du 16 novembre, la thèse de Valentin Faust, ingénieur de l’environnement, a été récompensée du prix Otto Jaag pour la protection des eaux. Celle-ci fournit d’importantes connaissances pour la...

Lors de la Journée de l’EPF du 16 novembre, la thèse de Valentin Faust, ingénieur de l’environnement, a été récompensée du prix Otto Jaag pour la protection des eaux. Celle-ci fournit d’importantes connaissances pour la fabrication d’engrais à partir d’urine humaine.
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Étés secs: la réutilisation d’eaux usées épurées pourrait être une solution

Depuis 2023, les surfaces agricoles peuvent être irriguées avec les eaux usées communales épurées dans plusieurs pays voisins de la Suisse (Photo: Adobe Stock).
17 octobre 2024 –

Avec le changement climatique, les étés chauds et secs se multiplient, avec un risque de pénurie d’eau dans certaines régions de Suisse. La réutilisation d’eaux usées épurées pourrait contribuer à régler ce problème. C’est ce qu’a...

Avec le changement climatique, les étés chauds et secs se multiplient, avec un risque de pénurie d’eau dans certaines régions de Suisse. La réutilisation d’eaux usées épurées pourrait contribuer à régler ce problème. C’est ce qu’a montré une équipe de l’Eawag sur mandat de l’OFEV et de plusieurs cantons. Les chercheuses et chercheurs expliquent aussi ce qu’il reste à faire pour que cette option devienne réalité. 
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Water Hub: Noveau film (en Anglais)

Publications

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.

Événements

24.06.​2025,
9h00
Elimination poussée de l'azote des eaux usées municipales

Cours d’approfondissement PEAK-VSA V60/25

04.12.​2025,
9h00
Eawag Dübendorf
Emissions et impact des particules de pneus dans l’environnement

Cours de base PEAK-B36/25

Projets de recherche

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
La gestion durable d'eaux potable et usées appliquée et mise en pratique dans le bâtiment modulaire NEST.

WaterHub au 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

Autres projets de recherche