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

Prizewinning master’s thesis

The Oswald Schulze Foundation in Aachen awarded Nicolas Neuenhofer’s master’s thesis third prize in 2024—a distinction that comes with prize money of 1,000 euros. (Photo: Eawag, Peter Penicka)
April 9, 2024 –

As part of his master’s thesis at Eawag, the environmental engineer Nicolas Neuenhofer delved into the topic of machine learning and developed a model that helps to gauge the removal of micropollutants from wastewater using...

As part of his master’s thesis at Eawag, the environmental engineer Nicolas Neuenhofer delved into the topic of machine learning and developed a model that helps to gauge the removal of micropollutants from wastewater using activated carbon filters. In recognition of this work, he has recently been awarded the Oswald Schulze Prize.
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Eawag presents one of its success stories on the sidelines of the WEF 2024

Eawag researchers Christa McArdell and Marc Böhler explain how ozone removes micropollutants in wastewater. (Photo: Eawag, Claudia Carle)
January 18, 2024 –

To coincide with the World Economic Forum (WEF) in Davos, the ETH Domain invited 50 dignitaries from the political, research and business spheres, to Davos and presented highlights from its current research. Eawag demonstrated how...

To coincide with the World Economic Forum (WEF) in Davos, the ETH Domain invited 50 dignitaries from the political, research and business spheres, to Davos and presented highlights from its current research. Eawag demonstrated how its work has successfully paved the way for advanced wastewater treatment.
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Swiss approach to modern wastewater treatment is honoured

Ozone is blown into the treated wastewater through these diffusers (WWTP Neugut, Dübendorf; photo: Max Schachtler) .
December 1, 2023 –

A team of seven current and former Eawag researchers will receive the Swiss Chemical Society’s Sandmeyer Prize in 2024 for the development of advanced wastewater treatment for the degradation of micropollutants using ozone. And...

A team of seven current and former Eawag researchers will receive the Swiss Chemical Society’s Sandmeyer Prize in 2024 for the development of advanced wastewater treatment for the degradation of micropollutants using ozone. And the most amazing thing is: Just about 15 years have passed between basic research and large-scale technical implementation. This incredible timetable was only possible thanks to the wealth of knowledge already available at Eawag and the fact that interdisciplinary collaboration is a matter of course at the Swiss aquatic research institute.
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Water Hub: new movie!

Publications

Bosshard, J., Eugster, F., Gulde, R., & Singer, H. (2024). Abwasser aus der Formulierung von Arzneimitteln. Wirkstoffeinträge in Schweizer Gewässer. Aqua & Gas, 104(3), 50-57. , Institutional Repository

Wirkstoffeinträge von formulierenden Pharmabetrieben führen häufig zu Spitzenkonzentrationen in kommunalen Abwasserreinigungsanlagen. Schweizweite Untersuchungen in Zusammenarbeit mit neun Betrieben zeigen das Ausmass der Einträge für unterschiedliche Abwasservorbehandlungen. Die Studie schliesst wichtige Kenntnislücken bezüglich der Abwasserbelastung von formulierenden Pharmabetrieben und zeigt Handlungsoptionen für die Unternehmen auf.
Brander, A., Wunderlin, P., Gulde, R., & Böhler, M. (2024). MV-Stufen Stabil Betreiben. Hilfreiche Betriebsparameter. Aqua & Gas, 104(1), 54-61. , Institutional Repository

Der Reinigungseffekt für Mikroverunreinigungen wird von ARA über periodische Messungen der Leitsubstanzen bestimmt. Für den täglichen Betrieb lassen sich zusätzlich anhand von UV-Messungen sowie anhand der dosierten Mengen an Ozon oder Aktivkohle zeitnahe Aussagen zur Reinigungsleistung machen.
Endres, L. S., Jacquin, C., González-Lemos, S., Rodríguez-Rodríguez, L., Sliwinski, J., Kaushal, N., … Stoll, H. M. (2024). Climatic and cave settings influence on drip water fluorescent organic matter with implications for fluorescent laminations in stalagmites. Quaternary Research, 118, 41-61. doi:10.1017/qua.2023.41, Institutional Repository

Speleothem fluorescence can provide insights into past vegetation dynamics and stalagmite chronology. However, its origin and especially the formation of fluorescent laminations in stalagmites are poorly understood. We conducted a year-long monthly monitoring of drip water fluorescence in La Vallina Cave (northern Iberian Peninsula) and compared the results to drip water chemistry and active speleothems from the same sites. Drip waters were analyzed using fluorescence spectroscopy and parallel factor analysis (PARAFAC). The resulting five-component model indicates contributions from vegetation, microbial activity, and bedrock. Intra-site fluorescence variability is mainly influenced by changes in overlying vegetation, water reservoir time, and respiration rates. Contrary to prevailing views, we find no systematic increase in drip water fluorescence during rainy conditions across drip sites and seasonal variations in drip water fluorescence are absent at a location where present-day speleothem layers form. Our findings challenge the notion of a higher abundance of humic-like fluorescence during the rainy season as the primary cause for layer formation and suggest additional controls on drip water fluorescence, such as bedrock interaction and microbial reprocessing. We also propose that growth rate may control the dilation of the fluorescence signal in stalagmites, indicating other potential mechanisms for fluorescent layer formation.
Faust, V., Vlaeminck, S. E., Ganigué, R., & Udert, K. M. (2024). Influence of pH on urine nitrification: community shifts of ammonia-oxidizing bacteria and inhibition of nitrite-oxidizing bacteria. ACS ES&T Engineering, 4(2), 342-353. doi:10.1021/acsestengg.3c00320, Institutional Repository

Urine nitrification is pH-sensitive due to limited alkalinity and high residual ammonium concentrations. This study aimed to investigate how the pH affects nitrogen conversion and the microbial community of urine nitrification with a pH-based feeding strategy. First, kinetic parameters for NH3, HNO2, and NO2- limitation and inhibition were determined for nitrifiers from a urine nitrification reactor. The turning point for ammonia-oxidizing bacteria (AOB), i.e., the substrate concentration at which a further increase would lead to a decrease in activity due to inhibitory effects, was at an NH3 concentration of 12 mg-N L-1, which was reached only at pH values above 7. The total nitrite turning point for nitrite-oxidizing bacteria (NOB) was pH-dependent, e.g., 18 mg-N L-1 at pH 6.3. Second, four years of data from two 120 L reactors were analyzed, showing that stable nitrification with low nitrite was most likely between pH 5.8 and 6.7. And third, six 12 L urine nitrification reactors were operated at total nitrogen concentrations of 1300 and 3600 mg-N L-1 and pH values between 2.5 and 8.5. At pH 6, the AOB Nitrosomonas europaea was found, and the NOB belonged to the genus Nitrobacter. At pH 7, nitrite accumulated, and Nitrosomonas halophila was the dominant AOB. NOB were inhibited by HNO2 accumulation. At pH 8.5, the AOB Nitrosomonas stercoris became dominant, and NH3 inhibited NOB. Without influent, the pH dropped to 2.5 due to the growth of the acid-tolerant AOB “Candidatus Nitrosacidococcus urinae”. In conclusion, pH is a decisive process control parameter for urine nitrification by influencing the selection and kinetics of nitrifiers.

Research Projects

By recovering nutrients from urine, we develop a sanitation system, which produces a valuable fertiliser

VUNA - Nutrient harvesting in South Africa
We develop reactors for the separate treatment of urine, feces and water directly in the toilet.

Blue Diversion AUTARKY – Sewage Treatment off the Grid
Inadequate access to microbiologically safe drinking water continuously threatens the health and well-being of more than a billion people, primarily in developing countries

GDM Gravity-Driven Membrane technology
The anthropogenic nitrogen input into coastal waters is becoming increasingly problematic due to eutrophication of our waters.

Nitrations- / Anammox process

Micro-sieving of municipal wastewater

Aerobic Granular Sludge
Modelling of aerobic granular sludge (AGS) reactors

Eawag Aerobic Granular Sludge (AGS) Model

More Research Projects