The initial value of recyclable material is significantly reduced if separated from other refuse only after collection or at disposal sites. Improved solid waste management at household and community level can help prevent this loss.

Experiments have revealed that planted drying beds are a promising technology for faecal sludge treatment in tropical climates. However, most of the current knowledge has been developed through lab-scale experiments. Full-scale planted drying beds have been in operation since 2008 at the Cambérène treatment facility in Dakar, Senegal. Monitoring and evaluation have resulted in important conclusions for scaling up and managing the critical start-up phase of this eco-technology.

Cutting edge technology developed for informal settlements of the Global South not only requires technical expertise, but also socio-cultural and socio-economic considerations at the early design phase. This is particularly important when developing an everyday object like a toilet, which is the aim of Eawag’s “Reinvent the Toilet” project.

Practitioners are increasingly aware of the fact that providing for example drinking water disinfection technologies, improved toilets or handwashing facilities will fail to lead to the desired health effects if used inadequately or not at all. Evidence-based behavioural change must therefore be a major component of any mitigation effort.

The incidence of diarrhoea was monitored and the risk factors for diarrhoea were identified in the rural community of Hanam, Vietnam, over a period of one year. Compared to adults without direct contact to wastewater and excreta during their agricultural activities, those in direct contact had a higher incidence of diarrhoea.

In the past few decades, various attempts were made to develop a sustainable sanitation model for the numerous small settlements scattering Egypt’s agricultural land. Yet, none of these initiatives turned into an upscalable model. The SECO-funded ESRISS Project (Egyptian-Swiss Research for Innovation in Sustainable Sanitation) seeks to understand why wide-scale replication has not occurred, bridge the gaps and develop an innovative and cost-effective system in partnership with the Egyptian Holding Company for Water and Wastewater (HCWW).

Understanding the sanitation situation and behaviour among urban slum dwellers is the focus of a joint four-year transdisciplinary NCCR North-South and EU Water Initiative Splash U-ACT research project. The research conducted in Kampala, Uganda, aims at understanding the main social and economic drivers as well as the constraints regarding access and sustained use of on-site sanitation facilities in poor urban contexts.

The public health situation of the population of Hanam Province in Vietnam is of great concern, as it is exposed daily to arsenic-contaminated drinking water. Optimising arsenic (As) removal efficiency of current sand filters at household level or switching to cleaner or As-free water sources is crucial to prevent or reduce community health risks.

Why are sanitation facilities like dry toilets or septic tanks so much more expensive in sub-Saharan Africa than in Asia? How can costs be reduced to affordable levels? A new Eawag/Sandec research project in collaboration with ETH-Nadel seeks to answer these questions.

High levels of fluoride in groundwater in the Ethiopian Rift Valley have raised concern among scientists in the past. Most studies to date have focused on investigating the distribution and concentration of fluoride in groundwater, but intake from food can also contribute to dental and skeletal fluorosis.

With passive sampling, contamination of rivers can be analysed more comprehensively than with spot sampling. The method is suitable for capturing spatial and temporal patterns of pollutant inputs. It can also be used to detect substances present in waters at concentrations below the limit of quantification – for example, PCBs in the Birs river.

Even at very low concentrations, organic micropollutants in natural waters can be harmful to aquatic organisms. Owing to technical constraints, analytical methods have so far been confined to the detection of a relatively small number of known compounds. With new methods, previously undetected substances can also be identified.

Algae, like other life forms, are subject to biorhythms: the abundance and diversity of phytoplankton vary from daytime to nighttime, as well as from season to season and over the depth of the water column. In research supported by the Swiss National Science Foundation, Eawag and the ETH Zurich have deployed a floating monitoring platform which – for the first time – is providing the high-resolution data that are needed to improve our understanding of the drivers of phytoplankton dynamics.

Traditional methods of assessing the effects of environmental toxicants are often inadequate – especially if these substances occur at low concentrations. But with the so-called omics methods, effects can be detected at the molecular level – for example, alterations of gene expression and protein profiles in green algae exposed to silver.

The fate of organic micropollutants in soils and natural waters is difficult to track using traditional methods. But with compound-specific isotope analysis, the isotopic composition of contaminants can be studied. This makes it possible, for example, to trace the origin of dishwasher detergents or to determine the degradation pathways of explosives.

Rapid economic and population growth in the Beijing-Tianjin region is leading to heavy eutrophication of the Haihe river system. Nutrient inputs derive mainly from wastewater. Although treatment plants have been constructed in some areas, these often operate beyond their projected capacity or with poor nutrient removal efficiency.

Passivsammler ermöglichen aussagekräftigere Analysen von Chemikalienbelastungen in Fliessgewässern als einzelne Stichproben. Die Methode eignet sich für eine räumlich und zeitlich differenzierte Erfassung von Schadstoffeinträgen. Damit lassen sich auch Stoffe nachweisen, deren Konzentrationen im Wasser unter der Bestimmungsgrenze liegen – zum Beispiel PCB in der Birs.

Organische Mikroverunreinigungen sind in Gewässern generell unerwünscht. Sie können Gewässerorganismen bereits in sehr niedrigen Konzentrationen schädigen. Bisherige Analysetechniken mussten sich technikbedingt auf den Nachweis weniger, bekannter Substanzen beschränken. Mit neuen Methoden lassen sich auch unentdeckte Stoffe erfassen.

Auch Algen haben einen Biorhythmus. Die Verteilung ihrer Masse, aber auch ihre Artenvielfalt ändern sich im Tag-Nacht-Wechsel ebenso wie über die Jahreszeit und die Seetiefe. Eine schwimmende Messplattform der Eawag und der ETH Zürich, unterstützt vom Nationalfonds, beschafft nun erstmals genügend hoch aufgelöste Daten, um dieser Dynamik und den treibenden Kräften dahinter auf die Spur zu kommen.

Herkömmliche Methoden erfassen die Auswirkungen von Umweltgiften auf Lebewesen oft nur ungenügend – insbesondere wenn diese in geringen Konzentrationen auftreten. Abhilfe können die so genannten Omik-Methoden schaffen. Mit ihnen lassen sich Effekte auf molekularer Ebene nachweisen, etwa dass eine Silberbelastung bei Grünalgen die Genaktivität und das Proteinprofil verändert.

Das Schicksal organischer Mikroverunreinigungen in Böden und Gewässern ist mit herkömmlichen Methoden schwierig zu verfolgen. Die Einzelstoff-Isotopenanalyse ermöglicht es, die Isotopenzusammensetzung von Schadstoffen zu untersuchen. Damit lassen sich zum Beispiel die Herkunft von Geschirrspülmitteln nachweisen oder die Abbauwege von Sprengstoff bestimmen.

Eine rasante wirtschaftliche Entwicklung und ein starkes Bevölkerungswachstum führen im Haihe-Flusssystem bei Peking zu einer massiven Überdüngung der Gewässer. Der Nährstoffeintrag erfolgt hauptsächlich über das Abwasser. Zwar existieren mancherorts Kläranlagen, doch viele arbeiten bereits heute über ihren Kapazitätsgrenzen oder eliminieren die Nährstoffe mangelhaft.

Switzerland’s hydropower sector is facing billion-franc challenges. What is required to meet these challenges are economically and ecologically acceptable ways of optimizing peak-load production and storing surplus electricity from new renewable sources of energy. In both cases, the interests of Switzerland and Europe would be served – and ideally there could be benefits for aquatic ecosystems as well as the electricity sector.

Endocrine-disrupting compounds, which enter surface waters mainly via wastewater discharges, can have adverse effects on aquatic organisms. Ecotoxicological test methods improve the measurement of these substances and the assessment of water quality, providing valuable decision support for reduction measures. For example, these methods can be used to evaluate additional treatment steps at wastewater treatment plants.

The reduction of phosphorus loads in Swiss lakes is a positive outcome of water pollution control efforts. But now, in order to increase fish yields on Lake Brienz and other waterbodies, members of the fishing community have called for phosphorus elimination to be reduced at local wastewater treatment plants. However, increases in phosphorus inputs to nutrient-poor lakes can lead to the extinction or merging of species, producing irreversible changes in aquatic ecosystems.

The habitat requirements of macroinvertebrates vary widely. Eawag is developing a model for the prediction of benthic community composition in surface waters. In the future, the model could be used to support integrated river management and to predict the possible consequences of different management options or climate change.

Freshwater ecosystems provide socioeconomic services, but their function is dependent on certain ecological requirements being met. Sustainable water resource management should therefore consider the needs of both humans and the environment. What this kind of approach could involve is shown by two research projects carried out on the Spöl and in the Sandey floodplain.

Die Schweizer Wasserkraft steht vor milliardenschweren Herausforderungen. Es gilt, wirtschaftlich und ökologisch verträgliche Lösungen für die optimierte Spitzenstromproduktion und Speicherung von Überschussstrom aus neuen erneuerbaren Quellen zu finden. Beides dient sowohl der Schweiz als auch Europa und im Idealfall können die Gewässer und die Stromwirtschaft gewinnen.

Hormonaktive Stoffe, die vor allem über das Abwasser in Oberflächengewässer gelangen, können die Gesundheit von Wassertieren beeinträchtigen. Ökotoxikologische Testmethoden verbessern die Messung und Bewertung dieser Substanzen. Sie liefern wichtige Entscheidungshilfen für Massnahmen zur Verminderung. So lässt sich mit ihnen die Wirkung zusätzlicher Reinigungsstufen in den Kläranlagen evaluieren.

Die Reduktion der Phosphorbelastung in den Seen ist ein Erfolg im Schweizer Gewässerschutz. Um die Erträge zu erhöhen, fordern Fischereikreise nun aber für den Brienzersee und andere Gewässer eine Verminderung der Phosphorelimination in den Kläranlagen. Die Zufuhr von mehr Phosphor kann in nährstoffarmen Seen allerdings zum Aussterben und Verschmelzen von Arten führen und verändert die Gewässerökosysteme unwiederbringlich.

Wirbellose Kleinlebewesen haben sehr verschiedene Ansprüche an ihren Lebensraum. Die Eawag entwickelt ein Computermodell, um die Zusammensetzung der Lebensgemeinschaften am Flussgrund vorherzusagen. Das Modell soll in Zukunft integratives Flussmanagement unterstützen und mögliche Konsequenzen verschiedener Managementmassnahmen oder des Klimawandels vorhersagen.

Gewässer erbringen sozioökonomische Leistungen, benötigen aber auch bestimmte ökologische Rahmenbedingungen, damit sie ihre Funktionen wahrnehmen können. Gefragt ist deshalb ein nachhaltiges Ressourcenmanagement, das die Bedürfnisse des Menschen wie auch der Umwelt berücksichtigt. Wie ein solches aussehen könnte, zeigen zwei Forschungsprojekte am Spöl und im Auengebiet Sandey.

Changes in the global climate are expected to have major impacts on agriculture. Sub-Saharan Africa, in particular, will experience declining yields. Using GIS models, Eawag is studying how climate change will affect agricultural output in this region, and how farmers can increase crop production – both in general terms and under changing climatic conditions.

During a career at Eawag which spanned almost 40 years, Willi Gujer helped to shape the urban water management sector both in Switzerland and internationally. As a researcher, he always attached great importance to training young specialists and reaching out to practitioners. Here, to mark his retirement, we look back over his career and celebrate his achievements.

The sun – our primary source of energy – powers the Earth’s climate system and hydrological cycle. But increasingly it also poses a hazard to our high-tech world. So it is important to improve our understanding of the sun, and long-term solar activity in particular. Ice cores allow us to look back over the past 10,000 years – and to make tentative predictions about future activity.

Engineered metal and metal oxide nanoparticles (NPs) are expected to agglomerate and partly dissolve, when introduced into aquatic environments. Toxic effects of some metal ions (e.g. Ag<SUP>+</SUP>, Cu<SUP>2+</SUP>, Zn<SUP>2+</SUP>) are very well documented. The observed toxic effects of nanoparticles may be caused by the particulate or dissolved form, or both. In this project, the dissolution of some widely used nanoparticles (Ag, ZnO, Cu-carbon coated and CuO) has been studied over days to weeks in natural water samples. The dissolved fraction of metals from nanoparticles was determined using DGT (Diffusion Gradients in Thin films), dialysis membrane (DM) and ultrafiltration (UF). The natural waters from a wastewater treatment plant effluent (WWTP Dübendorf), from the lakes Greifen, Lucerne and Cristallina (TI) greatly differed in pH, major ion concentrations and dissolved organic carbon (DOC). The dissolution was highly dependent on nanoparticle type and natural water composition. Relatively small amounts of Ag-NPs dissolved during the experimental period of 9 days. Dissolved Ag concentrations were below 1% of total Ag in water from the WWTP Dübendorf and from lakes Greifen and Lucerne, but higher with 3.7 % in water from Cristallina lake with lower pH 6.4. In contrast, most of ZnO-NPs present in suspension dissolved very fast (within first few hours) and almost completely, especially in the waters with lower pH (Cristallina lake). CuO-NPs also dissolved faster and more completely in water from Lake Cristallina. At the end of experimental period, most of Cu present in the suspension was in dissolved form. In contrast, Cu/C-NPs behaved similary in all four different natural waters and were removed from suspension, probably because of their hydrophobic characteristics, which cause agglomeration, adsorption and sedimentation. From the rest of Cu/C-NPs present in the suspensions (10%), around half dissolved during first two days. At the end of experimental period (9 days), only 2-5 % of total Cu introduced in the natural waters was in dissolved form. When the techniques for dissolved metal measurements are compared, clearly DGT and UF perform well in all types of natural waters (investigated until now), whereas DM gave only in few cases comparable results to the other methods These results indicate that NP dissolution may be an important process under conditions of natural waters or of wastewaters.

Background and objectives In response to the devastating Earthquake of January 12th 2010 and the cholera outbreak of October of that same year Oxfam Great Britain, Oxfam Quebec and Intermón Oxfam conducted public health promotion and cholera response in Haiti. Different promotion activities were applied which aimed at changing hygiene behavior by changing perceptions and beliefs about healthy behaviors amongst people affected by crisis. In February 2011 four Oxfam affiliates in Haiti in partnership with a team of behavior change researchers from Eawag launched the present research project to do an in-depth evaluation of the promotional activities that had been conducted with the goal of further improving the WASH situation for people in Haiti and worldwide by understanding how to make hygiene promotion more effective. The main focus of the research project was around the question which specific promotion activities were strongly associated with perceptions and beliefs about handwashing with soap and were thus capable of changing handwashing behavior at key times. Methods To address this question, 811 structured interviews with the primary caretaker of a household were conducted in May and June 2011 in camps and neighborhoods in Port-au-Prince, Gressier, Petit Goâve, Grand-Goâve, and Léogâne. Results Regression analysis revealed that attitudes, norms and ability beliefs are most important in determining handwashing behavior at key times while health risk beliefs and health knowledge are of only minor importance. In terms of promotion activities, regression and mediation analysis revealed hygiene radio spots, material distributions with instructions for use, information from friends or neighbors, and hygiene theater were strongly associated with feces and food related handwashing.1 In addition, radio programs with experts answering listener’s questions fostered feces related hand washing while community clubs were beneficial for food related handwashing. However, some of the promotion activities are negatively associated with handwashing at key times. Respondents who experienced a focus group, stickers, posters and paintings, and hygiene songs wash their hands less often after any contact with feces or before handling food than respondents who did not experience these promotion activities. Moreover, special hygiene days and home visits are negatively associated with food related handwashing as well. Further analyses revealed that a combination of effective promotion activities (e.g. radio spots, material distributions, and community clubs) is more effective than applying only one fostering promotion. On the down side it is more hampering when a combination of hindering promotion activities (e.g. focus group, stickers, posters, paintings, and hygiene songs) are experienced than if only one hindering promotion is experienced. However, if fostering and hindering promotion activities are experienced, the effectiveness of the fostering promotion activities is stronger, overlaying the effect of the hindering promotion activities. Conclusion In summary, some of the promotion activities which have been applied by Oxfam are positively associated with behavior, some are negatively associated, while other promotion activities have no effect at all. Accordingly, some of the promotion activities should be seriously revised and others although successful still have the potential to be improved. Carefully redesigning some activities, conducting pre-tests, and subsequently protocoling the behavior change effects of the promotion activities in the field is necessary to ensure reliable and effective promotion activities

Background and objectives In response to the drought in the Horn of Africa Oxfam America (OA) together with Gayo Pastoral Development Initiative (GPDI) implemented from February 2011 on an emergency WASH response in the Borena zone of Southern Oromia, Ethiopia. Different promotion activities were applied which aimed amongst others at increasing the frequency of handwashing with an agent (HWWA) at key times, by changing perceptions and beliefs (so called behavioral factors) about health behavior within the beneficiaries. The present study evaluates the promotion activities implemented in the OA drought response by examining which of the promotion activities are stronlgy associated with those behavioral factors explaining handwashing behavior. Based on the results promotion activities will be (re-)designed in such a way that they optimally target the critical behavioral factors and therewith change behavior sustainably. These new promotion activities will be implemented in the next intervention phase. Methods To address the study objectives, 463 structured interviews with the primary caregiver of a household and 151 household observations were conducted in February and March 2012 in 4 Kebeles: Madacho and Gololicha in Dire woreda, and Kancharo and Magole in Dillo woreda. Results Regression analysis revealed that severity, drive to nurture, disgust, social norms, hindrance and commitment are important in determining HWWA behavior at key times. Social norms by having the highest regression coefficient and only a mediocre prevalence in the communities so far have the highest potential to change behavior and should be targeted in future promotion activities. Mediation analysis revealed that only two promotion activities are beneficially related with the critical behavioral factors, and thus, with HWWA behavior: diarrhea leaflet and material distribution. Adverse associations with the behavioral factors and HWWA behavior are found for activities conducted to celebrate the Global Handwashing Day. The remaining six promotion activities which were implemented in the Borena WASH emergency have no significant association with the behavioral factors and with the behavior. Conclusion While diarrhea leaflet and material distribution are promising in changing HWWA behavior the remaining promotion activities should be carefully revised due to negative or insignificant associations with the behavioral factors and behavior. Future promotion activities should focus especially on social norms since this behavioral factor has the highest potential for changing HWWA behavior. For that, an intervention combining public commitment with constructing handwashing facilities would be a promising approach.

Scientists expect an increase in heavy rainfalls in Switzerland in the future because of climate change. During heavy rainfall, the wastewater system might not be able to cope with all the rainwater anymore, leading to surcharges of wastewater in combined sewer systems. Untreated wastewater can therefore reach surface waters, which is known as combined sewer overflows (CSOs). Wastewater can also overflow from manholes or sewers, thus flooding streets or cellars. With climate change, these events are expected to occur more often. It is possible to improve the wastewater system with structural measures to cope with such events, but the costs are high. Ultimately, this would result in an increase of the wastewater taxes paid by the population. The aim of our study was to elicit the willingness to pay of the Swiss population for improving the wastewater system in the context of climate change. We implemented an online survey representative of the Swiss population and interviewed 1’022 individuals from the three linguistic regions of Switzerland. We elicited the willingness to pay of the respondents using a conjoint choice analysis. Conjoint choice analysis entails the description of hypothetical scenarios where respondents are shown alternative representations of a policy and are asked to pick their most preferred option. In our study, respondents first received information on the wastewater system and on climate change to help them choosing between the different policy options. We focused on the following events: a) wastewater overflows in rivers and lakes; b) street flooding; or c) cellar flooding with wastewater. The results show that the Swiss people are concerned about the consequences of wastewater surcharges on the environment and on human health. Overall, 56% of the respondents would be willing to pay additional annual local taxes to reduce the risk of wastewater flooding or combined sewer overflows (CSOs). The average willingness to pay is about 240 CHF per person and year. This is in the same order of magnitude of the wastewater taxes they are paying today. On average, respondents would be willing to pay more to prevent CSOs (302 CHF, 71% of the respondents). The willingness to pay to prevent street flooding is about 237 CHF (with 53% of the respondents willing to pay). The willingness to pay to prevent wastewater flooding in cellars is about 184 CHF (with 43% of the respondents). One-to-one interviews indicated that the lower willingness to pay related to cellar flooding might be due to the fact that respondents think that measures against cellar floodings are rather a personal than a public responsibility. We want to emphasize that the estimation of the willingness to pay is based on hypothetical scenarios. For different reasons it is possible that the method over-estimates the absolute values of the willingness to pay. However, concretely for policy makers, our results clearly show that the population strongly values the protection of water bodies. Measures that reduce the effects of climate change on the wastewater system would likely be well perceived by the majority of the Swiss population, especially if ecological and health risks are reduced and accordingly communicated.

Dieses Fachgutachten ist Teil des Umweltverträglichkeitsberichts (UVB) 1. Stufe (Beilage 2 zum Hauptbericht) für ein Projekt von Repower, in welchem geplant ist, die beiden Seen Lago Bianco und Lago di Poschiavo als Speicherbecken für den Betrieb eines Pumpspeicherkraftwerkes mit einer in-stallierten Leistung von 1000 MW zu nutzen (Projekt Lagobianco). Die zu erwartenden Auswirkungen auf die Temperatur und die Partikelkonzentrationen in den beiden Seen wurden vorgängig im Rahmen der Machbarkeitsstudie mit Hilfe von Modellrechnungen mit einem gekoppelten zweidimensionalen Modell der beiden Seen berechnet und in zwei Berichten (Schmid et al., 2008; Schmid und Wüest, 2009) dokumentiert. In der vorliegenden Arbeit werden diese Berechnungen weiter vertieft und zusätzlich mit vier verschiedenen hydrologischen Szenarien und Wetterbedingungen von 29 Jahren durchgeführt. Dies erlaubt, einen Überblick über die zu erwartende Variabilität der verursachten Ver-änderungen zu gewinnen, und zu analysieren, unter welchen hydrologischen und meteorologischen Bedingungen die grössten Veränderungen zu erwarten sind.

ESRISS: Egyptian - Swiss Research on Innovations in Sustainable Sanitation

Dieses Faktenblatt hat die Ziele (i) den heutigen Kenntnisstand zu diffusen Emissionen von Mikroverunreinigungen aus Siedlungen zusammenzufassen und (ii) die Relevanz der Niederschlagswassereinleitungen auf lokaler und nationaler Ebene zu beurteilen. Dazu wurde Literatur ausgewertet und eine System- und Stoffflussanalyse durchgeführt. Die Untersuchung fokussiert auf diffuse urbane Stoff- und Quellenkombinationen, die über Mischwasserentlastungen und Regenwassereinleitungen (zusammen nachstehend als „Niederschlagswassereinleitungen“ bezeichnet) in die aquatische Umwelt gelangen.

Künftig soll der Zürichsee als Wärmeenergiequelle und als Wärmeenergiespeicher intensiver genutzt werden. Einerseits eignet sich das kühle Tiefenwasser des Sees im Sommer ideal zur Kühlung der urbanen Infrastruktur und zur Ableitung von Prozesswärme (Wüest und Imboden 1992). Andererseits kann dem relativ warmen Seewasser im Winter Wärme zur Heizung (Wärmepumpen) entzogen werden.<br /> Nutzung von Seewasser zu Heiz- und Kühlzwecken ist aus energiepolitischer Sicht erwünscht und kann bei Berücksichtigung der gesetzlichen und ökologischen Vorgaben voraussichtlich nachhaltig betrieben werden. In jüngster Vergangenheit ist eine markante Zunahme von Anlagen für die energetische Nutzung des Seewassers festzustellen. Es ist damit zu rechnen, dass diese Entwicklung - insbesondere bei der Kühlung von Gebäuden - in Zukunft weiterhin anhalten oder sich sogar noch verstärken wird. Basierend auf dem Konzept Energieversorgung 2050 der Stadt Zürich wurde abgeschätzt, dass für das untere Seebecken (vorwiegend Stadt Zürich) ein maximaler Bedarf von Wärme- und Kälteenergie durch Nutzung des Zürichsees von ~400 GWh pro Saison besteht (Mitteilung Felix Schmid, Stadt Zürich).<br /> Im vorliegenden Kurzbericht soll abgeschätzt werden, ob dieser Bedarf und allenfalls eine künftige Steigerung auf 800 GWh pro Saison das Potential des Seebeckens bei Zürich übersteigt und welche Rahmenbedingungen zu beachten sind, damit mittel- bis langfristig das Potential möglichst nachhaltig ausgeschöpft werden kann.