Eawag - Swiss Federal Institute of Aquatic Science and Technology

Dubendorf, Switzerland

Eawag - Swiss Federal Institute of Aquatic Science and Technology

Dubendorf, Switzerland

The Swiss Federal Institute of Aquatic Science and Technology is a Swiss water research institute and an internationally networked institution. As part of the Swiss Federal Institutes of Technology Domain, it is an institution of the Swiss Confederation.After its foundation in 1936 it concentrated on wastewater treatment and drinking water supplies. From these beginnings it has expanded into a multidiciplinary research institute with a focus on three primary research areas: water as a foundation of health and well-being, water as an essential factor in the functioning of our ecological systems, and strategies for the mitigation of water use conflicts. Nowadays, with a staff of over 500 employees, Eawag is actively engaged in research, teaching and consulting in all areas pertaining to water. The Eawag is based in Dübendorf near Zurich and Kastanienbaum near Lucerne. Eawag's overall aim is to ensure the sustainable use of water resources and infrastructure and to harmonize the ecological, economic and social interests associated with bodies of water. In doing so, the Eawag plays an important role in bridging research and practice. Wikipedia.

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Eawag - Swiss Federal Institute of Aquatic Science and Technology | Date: 2017-08-09

The disclosed invention consists of a water oxidation method, comprising the treatment of micropollutants in bromide-containing water with ozone and hydrogen peroxide in an ozonation reactor (1), reaching reproducible low and homogenously distributed ozone concentration in the ozonation reactor. This avoids any residual of ozone in solution and therefore BrO_(3)^(-) formation. This goal is reached by a controlled addition of hydrogen peroxide to the water in a first step. The solution is then introduced in a multiplicity of hollow fiber membranes (20) permeable to gas, extended along the inner space (10) of the ozonation reactor (1). In parallel, ozone is added from the ozone filled inner space (10) of the ozonation reactor (1) with a controlled concentration (partial pressure?) through the hollow fiber membrane walls (200) in a homogenously distributed way without gas bubbles into the fiber compartments (201) carrying the water/hydrogen peroxide solution with an adjustable flow rate all along the entire hollow fiber membrane length (L).

Mosler H.-J.,Eawag - Swiss Federal Institute of Aquatic Science and Technology
International Journal of Environmental Health Research | Year: 2012

Public health practitioners increasingly agree that it is not enough to provide people with water and sanitation hardware. Numerous approaches are used to tackle the software which means to ensure behavior change necessary to come along with the sanitation hardware. A review of these approaches reveals several shortcomings, most importantly that they do not provide behavioral change interventions which correspond to psychological factors to be changed. This article presents a sound psychological model, which postulates that for the formation of new habitual behavior, five blocks of factors must be positive with regard to the new behavior: risk factors, attitudinal factors, normative factors, ability factors, and self-regulation factors. Standardized tools for measuring the factors in face-to-face interviews are presented, and behavioral interventions are provided for each factor block. A statistical analysis method is presented, which allows the determination of the improvement potential of each factor. © 2012 Taylor and Francis Group, LLC.

Steinhilber F.,Eawag - Swiss Federal Institute of Aquatic Science and Technology
Astronomy and Astrophysics | Year: 2010

Context. Total solar irradiance (TSI) has been measured with space-based instruments since 1978. The TSI during the recent solar minimum in 2009 has been lower than the two former minima around the years 1986 and 1996, which points to a long-term decrease. Aims. In this study, we address the question of whether the observed decrease in the TSI is the result of evolving solar surface magnetism (sunspots and faculae). Methods. We use a TSI model that is solely based on solar surface magnetic phenomena (sunspots and faculae including network). The information needed for this model is derived from Carrington rotation magnetogram and photogram synoptic charts measured with the Michelson Doppler Imager (MDI) instrument on-board the Solar and Heliospheric Observatory (SOHO). By combining these data with solar atmosphere calculations, TSI is reconstructed. Results. The TSI is reconstructed from June 1996 to May 2010. From the solar minimum of 1996 to the solar maximum of 2004 the model reproduces the observations well, but it fails to explain the observed decrease in TSI in the solar minimum of 2009 and the very recent data of 2010. Conclusions. The difference between modeled and observed TSI might be the result of underrepresented weak magnetic fields in the Carrington rotation synoptic charts, an uncertainty in the TSI measurement, or a decline of the global temperature of the photosphere. If latter were true, this would have important implications for reconstructions of TSI in the past. In order to study if an underrepresentation of weak magnetic fields in the Carrington rotation synoptic charts is the explanation for the difference between our model and the observation, full-disk images with higher spatial and temporal resolution should be analyzed in future. © 2010 ESO.

Ackermann M.,ETH Zurich | Ackermann M.,Eawag - Swiss Federal Institute of Aquatic Science and Technology
Nature Reviews Microbiology | Year: 2015

Most microbial communities consist of a genetically diverse assembly of different organisms, and the level of genetic diversity plays an important part in community properties and functions. However, biological diversity also arises at a lower level of biological organization, between genetically identical cells that reside in the same microenvironment. In this Review, I outline the molecular mechanisms responsible for phenotypic heterogeneity and discuss how phenotypic heterogeneity allows genotypes to persist in fluctuating environments. I also describe how it promotes interactions between phenotypic subpopulations in clonal groups, providing microbial groups with new functionality. © 2015 Macmillan Publishers Limited. All rights reserved.

Egli T.,Eawag - Swiss Federal Institute of Aquatic Science and Technology
Water Research | Year: 2010

Availability of carbon/energy sources and temperature are the two environmental factors that severely restrict heterotrophic growth in most ecosystems. DOC concentrations in ground, drinking and surface waters are typically in the range of 0.5-5 mg/L, but most of this is present in a polymeric, inaccessible form for microbes. Concentrations of microbiologically available carbon compounds (so-called assimilable organic carbon, AOC) are usually in the range of 10-100 μg/L, those of individual sugars or amino acids are not higher than a few μg/L. Until recently microbiologists assumed that such nutrient-poor (oligotrophic) environments are " deserts" for life, and that the majority of bacterial cells seen in the microscope are dead, dormant or at least severely starved. Nevertheless, despite the low concentrations of available carbon compounds, bacterial cell numbers recorded in these environments typically are in the range of 105-106 per mL. Over the last years, we have learnt that most of these microbes are perfectly alive, metabolizing and ready to grow when given the chance. Hence, microbes have adapted and developed strategies to cope with this situation.Laboratory studies with pure cultures suggest that bacterial cells have developed two strategies to live under such conditions. The first strategy is to perform a " multivorous" way of life by taking up and metabolizing dozens of different carbon substrates simultaneously (i.e., they are NOT specializing on a particular substrate, which they can take up with very high affinity). This " mixed substrate growth" equips the cell with a kinetic advantage and metabolic flexibility. Simultaneous utilization of a multitude of carbon substrates allows fast growth at minute concentrations of individual substrates. The second strategy is to minimize maintenance requirements (unfortunately we still know little about how this is achieved).Recently, flow cytometry has been employed to study microbial growth in very dilute, nutrient-poor environments. The technique allows fast and easy quantification of microbial growth of natural bacterial communities, including " uncultivable" members, under environmental conditions. When combined with strain-specific fluorescent immunoprobes, this technique allows investigation of the growth and competition of pathogens with the indigenous microbial flora. This method is particularly suited for studying questions concerning microbial growth and survival in drinking water systems. © 2010 Elsevier Ltd.

Ammann A.A.,Eawag - Swiss Federal Institute of Aquatic Science and Technology
Journal of Chromatography A | Year: 2010

Based on gradient anion exchange chromatography (AEC), a new strategy in As-speciation was evaluated. A narrow bore chromatographic system with lower flow rates (≤300 μL) well suitable for the low flow requirements of higher efficiency nebulizers was splitless coupled to a high resolution sector field ICP MS. The AEC system takes full advantage of the detector sensitivity allowing more diluted samples (50-100 times) to be injected, delivering substantially less sample matrix to the column and a lower eluent load to the plasma. The unique plasma compatibility of the NH4NO3-eluent salt used in this study enabled high linear salt ramps in gradient applications, highly reproducible retention times (±1%) and detection limits in the low ng/L range. The separation conditions were applied on two different polymeric anion-exchangers: a low capacity, weakly hydrophobic material (AS11, Dionex) and a more frequently used higher capacity, higher hydrophobic material (AS7, Dionex). On both columns, As-species (As(III/V), MMA, DMA, AsB) and Cl- were separated in less than nine minutes and co-elution was circumvented by adapting the separation pH to the optimal column selectivity. The key-advantage of the NH4NO3-eluent is that it can adopt any separation pH without compromising the eluent strength which is not possible with all other eluents used so far. The influences of chloride and methanol were investigated and found not to affect the chromatographic performance. Column deposits caused strong reversible As(v) adsorption which reduced As(v) to As(III). A corresponding phosphate excess in the injected sample eliminated the adsorption and prevented artefacts in As(v)/As(III) ratios. The method applied to ground water samples provided robust separations and is compatible with any sample preservation procedure. © 2010 Elsevier B.V. All rights reserved.

Ingold K.,Eawag - Swiss Federal Institute of Aquatic Science and Technology
Land Use Policy | Year: 2014

Different socio-economic and environmental drivers lead local communities in mountain regions to adapt land use practices and engage in protection policies. The political system also has to develop new approaches to adapt to those drivers. Local actors are the target group of those policy approaches, and the question arises of if and how much those actors are consulted or even integrated into the design of local land use and protection policies. This article addresses this question by comparing seven different case studies in Swiss mountain regions. Through a formal social network analysis, the inclusion of local actors in collaborative policy networks is investigated and compared to the involvement of other stakeholders representing the next higher sub-national or national decisional levels. Results show that there is a significant difference (1) in how local actors are embedded compared to other stakeholders; and (2) between top-down versus bottom-up designed policy processes. © 2014 Elsevier Ltd.

Altermatt F.,Eawag - Swiss Federal Institute of Aquatic Science and Technology
Aquatic Ecology | Year: 2013

The influence of spatial processes on diversity and community dynamics is generally recognized in ecology and also applied to conservation projects involving forest and grassland ecosystems. Riverine ecosystems, however, have been for a long time viewed from a local or linear perspective, even though the treelike branching of river networks is universal. River networks (so-called dendritic networks) are not only structured in a hierarchic way, but the dendritic landscape structure and physical flows often dictate distance and directionality of dispersal. Theoretical models suggest that the specific riverine network structure directly affects diversity patterns. Recent experimental and comparative data are supporting this idea. Here, I provide an introduction on theoretical findings suggesting that genetic diversity, heterozygosity and species richness are higher in dendritic systems compared to linear or two-dimensional lattice landscapes. The characteristic diversity patterns can be explained in a network perspective, which also offers universal metrics to better understand and protect riverine diversity. I show how appropriate metrics describing network centrality and dispersal distances are superior to classic measures still applied in aquatic ecology, such as Strahler order or Euclidian distance. Finally, knowledge gaps and future directions of research are identified. The network perspective employed here may help to generalize findings on riverine biodiversity research and can be applied to conservation and river restoration projects. © 2013 Springer Science+Business Media Dordrecht.

Altermatt F.,Eawag - Swiss Federal Institute of Aquatic Science and Technology
Global Change Biology | Year: 2012

Many species are becoming active earlier in the season as the climate becomes warmer. In parallel to phenological responses to climate change, many species have also been affected by habitat changes due to anthropogenic land use. As habitat type can directly affect microclimatic conditions, concurrent changes in climate and habitat could have interacting effects on the phenology of species. Temperature-related shifts in phenology, however, have mostly been studied independent of habitat types. Here, I used long-term data from a highly standardized monitoring program with 519 transects to study how phenology of butterflies is affected by ambient temperature and habitat type. I compared forests, agricultural areas and settlements, reflecting three major land use forms, and considered butterfly species that were observed in all three of these habitats. Seasonal appearance of the butterflies was affected both by the ambient temperature and the habitat type. As expected, warmer temperatures led to an overall advancement of the appearance and flight period of most species. Surprisingly, however, phenology of species was delayed in settlement habitats, even though this habitat type is generally associated with higher temperatures. A possible explanation is dispersal among habitat types, such that source-sink effects affect local phenology. When there is little productivity in settlement areas, observed butterflies may have immigrated from forest or agricultural habitats and thus appear later in settlements. My findings suggest that a spillover of individuals among habitats may affect phenology trends and indicate that phenological studies need to be interpreted in the context of habitat types. This becomes especially important when defining strategies to prevent or mitigate effects of climate and land-use changes on phenology and abundance of species. © 2012 Blackwell Publishing Ltd.

Pearse I.S.,Cornell University | Altermatt F.,Eawag - Swiss Federal Institute of Aquatic Science and Technology
Ecology Letters | Year: 2013

Humans are altering the global distributional ranges of plants, while their co-evolved herbivores are frequently left behind. Native herbivores often colonise non-native plants, potentially reducing invasion success or causing economic loss to introduced agricultural crops. We developed a predictive model to forecast novel interactions and verified it with a data set containing hundreds of observed novel plant-insect interactions. Using a food network of 900 native European butterfly and moth species and 1944 native plants, we built an herbivore host-use model. By extrapolating host use from the native herbivore-plant food network, we accurately forecasted the observed novel use of 459 non-native plant species by native herbivores. Patterns that governed herbivore host breadth on co-evolved native plants were equally important in determining non-native hosts. Our results make the forecasting of novel herbivore communities feasible in order to better understand the fate and impact of introduced plants. © 2013 John Wiley & Sons Ltd/CNRS.

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