Eawag - Swiss Federal Institute of Aquatic Science and Technology

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.

The contribution in the German pavilion at the Biennale of Architecture is more than just an exhibition. It wants to provide an action framework for a new building culture. (Photo: ARCH+ SUMMACUMMFEMMER BÜRO JULIANE GREB)

May 23, 2023 –

On Saturday, 20 May, the 18th Biennale of Architecture in Venice opened its doors. In the German pavilion, which focuses on building in existing contexts and the recycling economy, also the Nutrient Harvester developed at Eawag is...

On Saturday, 20 May, the 18th Biennale of Architecture in Venice opened its doors. In the German pavilion, which focuses on building in existing contexts and the recycling economy, also the Nutrient Harvester developed at Eawag is demonstrated. It processes the urine from two on-site dry separation toilets into fertiliser.

In close exchange with various universities in Switzerland and abroad, Eawag is committed to the education of undergraduate and doctoral students in natural, engineering and social sciences. In 2022, Eawag employees supervised 149 doctoral theses – such as that of Dorothee Kurz. In collaboration with ETH Zurich, the engineer in Joaquin Jimenez-Martinez’s research group is investigating how bacteria form biofilms in soils and groundwater aquifers. To do this, she works with simplified models that simulate the natural environment. (Photo: Eawag, Alessandro Della Bella)

May 11, 2023 –

The aquatic research institute Eawag has published its latest annual report and looks back on the year 2022. Water is at the heart of the most important environmental issues.

The four founders of the Eawag spin-off (Photo: Eawag, Peter Penicka)

May 9, 2023 –

Environmental engineer Wenzel Gruber and microbiologist Robert Niederdorfer – both Eawag postdocs – founded the spin-off Upwater together with two other partners at the beginning of November 2022. It offers measurements for...

Environmental engineer Wenzel Gruber and microbiologist Robert Niederdorfer – both Eawag postdocs – founded the spin-off Upwater together with two other partners at the beginning of November 2022. It offers measurements for wastewater treatment plants to support them in reducing process instabilities, greenhouse gas emissions as well as energy consumption.

Ballikaya, P., Brunner, I., Cocozza, C., Grolimund, D., Kaegi, R., Murazzi, M. E., … Cherubini, P. (2023). First evidence of nanoparticle uptake through leaves and roots in beech (Fagus sylvatica L.) and pine (Pinus sylvestris L.). Tree Physiology, 43(2), 262-276. doi:10.1093/treephys/tpac117, Institutional Repository

Ballikaya, P., Brunner, I., Cocozza, C., Grolimund, D., Kaegi, R., Murazzi, M. E., … Cherubini, P. (2023). Nanoparticles are everywhere, even inside trees. Chimia, 77(4), 256. doi:10.2533/chimia.2023.256, Institutional Repository

Bou-Sarkis, A., Paul, E., Girbal-Neuhauser, E., Derlon, N., & Bessiere, Y. (2023). Detection of gel-forming polymers via calcium crosslinking, applied to the screening of extracellular polymeric substances extracted from biological aggregates. Gels, 9(2), 157 (14 pp.). doi:10.3390/gels9020157, Institutional Repository

Brison, A., Rossi, P., & Derlon, N. (2023). Single CSTR can be as effective as an SBR in selecting PHA-storing biomass from municipal wastewater-derived feedstock. Water Research X, 18, 100165 (13 pp.). doi:10.1016/j.wroa.2023.100165, Institutional Repository

A key step for the production of polyhydroxyalkanoates (PHAs) from organic waste streams is the selection of a biomass with a high PHA-storage capacity (selection-step), which is usually performed in sequencing batch reactors (SBR). A major advancement would be to perform such selection in continuous reactors to facilitate the full-scale implementation of PHA production from municipal wastewater (MWW)-derived feedstock. The present study therefore investigates to what extent a simple continuous-flow stirred-tank reactor (CSTR) represents a relevant alternative to anSBR. To this end, we operated two selection reactors (CSTR vs. SBR) on filtered primary sludge fermentate while performing a detailed analysis of the microbial communities, and monitoring PHA-storage over long-term (∼150 days) and during accumulation batches. Our study demonstrates that a simple CSTR is as effective as an SBR in selecting biomass with high PHA-storage capacity (up to 0.65 gPHA gVSS⁻¹) while being 50% more efficient in terms of substrate to biomass conversion yields. We also show that such selection can occur on VFA-rich feedstock containing nitrogen (N) and phosphorus (P) in excess, whereas previously, selection of PHA-storing organisms in a single CSTR has only been studied under P limitation. We further found that microbial competition was mostly affected by nutrient availability (N and P) rather than by the reactor operation mode (CSTR vs. SBR). Similar microbial communities therefore developed in both selection reactors, while microbial communities were very different depending on N availability. Rhodobacteraceae gen. were most abundant when growth conditions were stable and N-limited, whereas dynamic N- (and P-) excess conditions favoured the selection of the known PHA-storer Comamonas, and led to the highest observed PHA-storage capacity. Overall, we demonstrate that biomass with high storage capacity can be selected in a simple CSTR on a wider range of feedstock than just P-limited ones.