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.

En savoir plus

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.
En savoir plus

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.
En savoir plus

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. 
En savoir plus

Water Hub: Noveau film (en Anglais)

Publications

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).
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.
Crosset-Perrotin, G., Moraz, A., Portela, R., Alcolea-Rodriguez, V., Burrueco-Subirà, D., Smith, C., … Fairbrother, D. H. (2025). Production, labeling, and applications of micro- and nanoplastic reference and test materials. Environmental Science: Nano. doi:10.1039/d4en00767k, Institutional Repository

Challenges inherent to the extraction of micro- and nanoplastics (MNPs) from the environment, combined with the limited range of commercially available MNPs, have prompted an increasing number of researchers to generate in-house reference and test MNPs. The first part of this review provides a comprehensive overview of existing MNP production methods, including top-down and bottom-up fabrication techniques. Strengths and weaknesses of different methods are compared and contrasted, and the potential for optimization and control over MNP properties is discussed. Methods to label and to artificially weather MNPs before, during, or after production, as well as appropriate dispersion protocols for introducing MNPs into different media, are also covered. The second part of this review focuses on how reference and test MNPs have been implemented in different types of studies, categorized as toxicity, uptake, fate, and monitoring. Given the wide range of properties needed to fully define MNPs, we propose a set of essential properties that need to be characterized depending on the study type. Looking forward, we suggest future needs, not only in the creation of reference MNPs, but also in experimental protocols that would help to better understand the behavior and impacts of MNPs. Overall, this review aims to provide the necessary information to guide researchers in decision-making regarding which reference MNPs are most appropriate to answer their specific research questions and to serve as a framework that will contribute to obtaining reliable, benchmarked data urgently needed to develop consensus on the fate and risk posed by MNPs.
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.

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