Wings

Water and sanitation innovations for non-grid solutions – an inter- and transdisciplinary strategic research program

Wings strives to develop novel non-grid water and sanitation systems that can function as comparable alternatives to network-based systems. We do this by:

  • Studying such systems from a variety of different perspectives (engineering, decision analysis, development studies, transition and innovation studies, and behavioral studies)
  • Working in close collaboration with key stakeholders from different sectors and decision levels
  • Pursuing research in different socio-economic contexts (research pillars), ranging from industrialized countries to emerging and developing countries
  • Addressing conceptual and methodological issues that link and relate existing research projects in different contexts (transversal projects)
  • Building on current and past research projects in the field of urban water management

Background

The management of urban water systems has been a core responsibility of civil society throughout history. This reflects the central importance of these systems for human welfare and environmental protection. The current conventional approach to urban water management builds on well-established socio-technical systems that have evolved over the last century and have solved most of the water- and hygiene-related problems afflicting OECD countries in the past. These predominantly centralized and networked systems reliably treat and provide drinking water and safely transport, treat, and dispose wastewater. Challenges are posed, however, by population growth (both increases and decreases), climate change, emerging contaminants, as well as by the need to rehabilitate and replace aging infrastructure.

Though there is still an ongoing debate whether there is a need for new approaches in OECD countries, leading research institutes, international organizations and national governments are increasingly acknowledging that the conventional approach to urban water management cannot be the only solution for rapidly expanding cities in low- and middle-income countries in Africa, Asia and Latin America. With centralized and networked urban water systems out of reach for a large part of the global urban population, there is an urgent need for developing fundamentally new approaches, i.e. more flexible, cost-effective, resource-efficient non-grid systems that are able to cope with current and future urban water challenges.

Team

Program management

Dr. Sabine Hoffmann Group Leader, Group: ITD Tel. +41 58 765 6818 Send Mail
Dr. Lisa Deutsch Postdoc, Group: ITD Tel. +41 58 765 5326 Send Mail

Program team

SWW

Prof. Dr. Max Maurer Tel. +41 58 765 5386 Send Mail

ENG

Prof. Dr. Eberhard Morgenroth Tel. +41 58 765 5539 Send Mail
Prof. Dr. Kai Udert Tel. +41 58 765 5360 Send Mail

Sandec

Dr. Christian Zurbrügg Tel. +41 58 765 5423 Send Mail
Dr. Christoph Lüthi Dr. Eng. Infrastructure Planning Tel. +41 58 765 5614 Send Mail

ESS

Prof. Dr. Bernhard Truffer Group leader, Group Cirus Tel. +41 58 765 5670 Send Mail
Dr. Christian Binz Group Leader, Group: Cirus Tel. +41 58 765 5030 Send Mail
Dr. Nadja Contzen Group leader, Group: EHP Tel. +41 58 765 6892 Send Mail
Dr. Sabine Hoffmann Group Leader, Group: ITD Tel. +41 58 765 6818 Send Mail
Dr. Lisa Deutsch Postdoc, Group: ITD Tel. +41 58 765 5326 Send Mail

Research pillars and projects

We organize our research within four research pillars. Each pillar covers a typical socio-technical system configuration. The program builds on current and past research activities in the involved departments of Eawag and aims to add value to these projects.

Wings Disconnect

Wings Disconnect identifies the conditions for decentralized water systems in contexts with well-established governance structures, medium to high incomes and high degrees of centralization. Compared with the dominating approach of water supply and sewer networks, decentralized systems promise to respond more favorably to new requirements such as rapid demographic variation, climate change or other planning uncertainties. Additionally, there is a growing unease that it might not be financially sustainable to continue to maintain the existing aging pipe networks.

Wings Disconnect provides the scientific base for identifying whether system change towards non-grid-connected water and sanitation solutions could alleviate these concerns and improve the financial sustainability of urban water infrastructures. To do this, we elaborate where and when it is possible to disconnect from the centralized system and implement non-grid-connected systems (particularly small treatment plants) and identify potential infrastructure transition paths. This includes developing methods to determine the optimal degree of infrastructural centralization, quantify the performance of entire systems, identify industrial opportunities, and support decision-making over time.

Current Projects

We are identifying the challenges of modular infrastructure systems for the Swiss economy and society using the example of urban water management.

COMIX: Challenges and Opportunities of Modular water Infrastructures
Project aim is participative decision support for the long-term transition to innovative wastewater infrastructures.

Decision-making for wastewater infrastructure transitions
Decentralisation changes wastewater quantity and quality that is discharged to the sewer. We investigate the effects of these changes on the operation of existing centralised sewer systems.

Transition to decentralised wastewater treatment systems - its effects on the operation of sewers

Past Projects

How can the overall performance of distributed treatment systems be estimated and maintained?

Model-based monitoring and management of distributed treatment systems (DSyM)
The aim of this project is to gain more insight about sustainable infrastructure management and to develop tools and methods for complex decision making for infrastructure planning.

Sustainable Network Infrastructure Planning (SNIP)

Wings Hybrid

Wings Hybrid investigates new models and methods to recycle nutrients, water and energy in future cities, particularly within the context of climate change. Conventionally, mixed wastewater is separated and treated in centralized wastewater treatment plants. We aim to establish viable alternatives for full-scale applications that collect and treat the wastewater flows separately according to the type and concentration of their contaminants. By doing so, water, nutrients and energy can easily be recovered, thus increasing water and energy productivity.

Wings Hybrid develops further urine separation and treatment to reuse anthropogenic nutrients in agriculture, as well as greywater treatment, to regenerate water with high chemical and microbial quality. This includes technical development and optimization through practical trials in a living lab, implementation of demonstration projects and collaboration with industrial partners.

Current Projects

We develop reactors for the separate treatment of urine, feces and water directly in the toilet.

Blue Diversion AUTARKY – Sewage Treatment off the Grid
NEST building
Sustainable urban water and wastewater management applied and implemented in the modular NEST building.

WaterHub at NEST
Serious games and gamification are increasingly used to engage stakeholders. We study whether and how they make decision analysis more participatory.

Environmental Decision Analysis with Games - Edanaga

Past Projects

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

VUNA - Nutrient harvesting in South Africa

Wings Emerging

Wings Emerging explores innovation in emerging markets characterized by rapid urbanization, an expanding middle-income population and overall economic growth, leading to rising living standards, increasing construction activities and growing resource demands (water, energy, services, etc.). Because of these particular characteristics, we assume that new urban development areas in emerging markets are among the most promising potential lead-markets for innovative non-grid-connected solutions that encompass water supply, wastewater treatment, waste disposal and energy supply in a holistic way.

Wings Emerging aims to inspire and support decision makers and niche players on how to transition towards such holistic solutions that allow for meeting growing demands while recovering resources. This includes analyzing the relevant capabilities necessary to succeed with such innovations, studying innovation paths to introduce non-grid-connected solutions and exploring barriers and drivers for their diffusion.

Current Projects

RADEC seeks to unravel how emerging countries can simultaneously achieve industrial leapfrogging and environmental sustainability transition by analyzing the industrial and socio-technical aspects of decentralized water and sanitation systems in China, India and South Africa.

RADEC: Radical Development for Emerging Countries
4S is assessing small-scale sanitation systems in South Asia to provide policy recommendations for improved sanitation system design, implementation and O&M.

4S: Small-Scale Sanitation Scaling-Up

Wings Informal

Wings Informal analyzes non-grid solutions for some of the most intractable, complex and rapidly expanding built environments in the developing world: informal settlements. Residents of these areas are disadvantaged as they lack formal access to land, housing and basic urban services. Solutions will therefore have to build on sound technological approaches, while also meeting the specific needs and specific resource constraints that are found in this context.

Understanding the broader complexities of current, heterogeneous sanitation systems with particular focus on the interfaces between these systems is the aim of Wings Informal. This includes analyzing the enabling environments that support or hinder the successful introduction of these solutions, exploring the scaling conditions for business models with particular focus on container-based systems, and identifying the challenges and opportunities related to scaling innovations in informal settlements.

Current Projects

The aim of CWIS research is to develop a method that synthesizes existing information about the sanitation landscapes of cities in India and that presents comprehensive sanitation solutions.

Citywide Inclusive Sanitation (CWIS)
We seek to understand how formal and informal institutions, planning procedures and resources drive or constrain informal settlements upgrading in Sub Saharan Africa cities.

SUSIS: Sanitation upgrading strategies for informal settlements

Past Projects

Development of systematic but generic methods for the generation of locally appropriate sanitation system options and for the quantification of sustainability performance indicators.

Generation and Assessment of Sanitation Systems for Strategic Planning (GRASP)
The proposal analyzes possible transition pathways in basic services, focusing specifically on the case of Nairobi, Kenya.

SuSARA: Sustainability Transitions of Sanitation Regimes
In this project, we work with organizations from around the globe to identify factors for managing water kiosks sucessfully

Business Innovations for making water kiosks more successful
In this project, we collaborate with various organizations to study the role of business innovation in the scaling process of sanitation services.

Business innovations for scaling up sanitation services
In this project, we apply Business Model Thinking to create promising business models around innovative water and sanitation technologies

Business model thinking for poverty alleviation

Wings Transversal

Transversal projects projects bundle conceptual and methodological needs of the pillars and/or the overall program. By doing so, they strengthen the connection within the interdisciplinary research team.

Current Projects

The INTEGRATE project aims at strengthening inter- and transdisciplinary integration within and across the strategic research program Wings.

INTEGRATE - Strengthening inter- and transdisciplinarity

Perceived distributive justice and acceptance of decentralised water and wastewater systems

Fair Wings: Fair distribution of Wings systems
The Lighthouse Project focuses on visible examples of onsite and decentralised urban water management systems, which will play a key role in enabling sustainability transitions.

Lighthouse

Publications

Urban Water Management

Assessing transitions through socio-technical configuration analysis – a methodological framework and a case study in the water sector

Classic accounts of transitions research have predominantly built on reconstructions of historical transition processes and in-depth case studies to identify and conceptualize socio-technical change. While such approaches have substantively improved our understanding of transitions, they often suffer from methodological nationalism and a lack of generalizability beyond spatial and sectoral boundaries. To address this gap, we propose a novel methodology – socio-technical configuration analysis (STCA) – to map and measure socio-technical alignment processes across time and space. STCA provides a configurational and dynamic perspective on how social and technical elements get aligned into "configurations that work", allowing for the identification of differentiated transition trajectories at and across spatial and sectoral contexts. The methodology's value is illustrated with the empirical case of an ongoing shift from centralized to more modular infrastructure configurations in the global water sector. Building on this illustration, we outline potential contributions of STCA to configurational theorizing in transition studies, sketching the contours of what we believe could become a generative epistemological approach for this field.
Heiberg, J.; Truffer, B.; Binz, C. (2022) Assessing transitions through socio-technical configuration analysis – a methodological framework and a case study in the water sector, Research Policy, 51(1), 104363 (19 pp.), doi:10.1016/j.respol.2021.104363, Institutional Repository

A simplified sanitary sewer system generator for exploratory modelling at city-scale

Future climatic, demographic, technological, urban and socio-economic challenges call for more flexible and sustainable wastewater infrastructure systems. Exploratory modelling can help to investigate the consequences of these developments on the infrastructure. In order to explore large numbers of adaptation strategies, we need to re-balance the degree of realism of sewer network and ability to reflect key performance characteristics against the model's parsimony and computational efficiency. We present a spatially explicit algorithm for creating sanitary sewer networks that realistically represent key characteristics of a real system. Basic topographic, demographic and urban characteristics are abstracted into a squared grid of 'Blocks' which are the foundation for the sewer network's topology delineation. We compare three different pipe dimensioning approaches and found a good balance between detail and computational efficiency. With a basic hydraulic performance assessment, we demonstrate that we attain a computationally efficient and high-fidelity wastewater sewer network with adequate hydraulic performance. A spatial resolution of 250 m Block size in combination with a sequential Pipe-by-Pipe (PBP) design algorithm provides a sound trade-off between computational time and fidelity of relevant structural and hydraulic properties for exploratory modelling. We can generate a simplified sewer network (both topology and hydraulic design) in 18 s using PBP, versus 36 min using a highly detailed model or 1 s using a highly abstract model. Moreover, this simplification can cut up to 1/10th to 1/50th the computational time for the hydraulic simulations depending on the routing method implemented. We anticipate our model to be a starting point for sophisticated exploratory modelling into possible infrastructure adaptation measures of topological and loading changes of sewer systems for long-term planning.
Duque, N.; Bach, P. M.; Scholten, L.; Fappiano, F.; Maurer, M. (2022) A simplified sanitary sewer system generator for exploratory modelling at city-scale, Water Research, 209, 117903 (12 pp.), doi:10.1016/j.watres.2021.117903, Institutional Repository

Overcoming the harmony fallacy: how values shape the course of innovation systems

The technological innovation systems (TIS) framework is one of the dominant perspectives in transitions studies to analyze success conditions and system failures of newly emerging technologies and industries. So far, TIS studies mostly adopted a rather harmonious view on the values of actors and by this were unable to address competition, conflicts and, in particular, battles over diverging directionalities within the system. To empirically assess this potential “harmony fallacy”, we identify values as part of underlying institutional logics of major organizations in the field of modular water technologies in Switzerland by means of 26 expert interviews. We show how logics may condition collaboration patterns and technological preferences. This analysis inspires key conceptual tasks of innovation system analysis, like the identification of system failures, the setting of appropriate system boundaries and the formulation of better policy recommendations.
Heiberg, J.; Truffer, B. (2022) Overcoming the harmony fallacy: how values shape the course of innovation systems, Environmental Innovation and Societal Transitions, 42, 411-428, doi:10.1016/j.eist.2022.01.012, Institutional Repository

State of the art of urine treatment technologies: a critical review.

Over the last 15 years, urine treatment technologies have developed from lab studies of a few pioneers to an interesting innovation, attracting attention from a growing number of process engineers. In this broad review, we present literature from more than a decade on biological, physical-chemical and electrochemical urine treatment processes. Like in the first review on urine treatment from 2006, we categorize the technologies according to the following objectives: stabilization, volume reduction, targeted N-recovery, targeted P-recovery, nutrient removal, sanitization, and handling of organic micropollutants. We add energy recovery as a new objective, because extensive work has been done on electrochemical energy harvesting, especially with bio-electrochemical systems. Our review reveals that biological processes are a good choice for urine stabilization. They have the advantage of little demand for chemicals and energy. Due to instabilities, however, they are not suited for bathroom applications and they cannot provide the desired volume reduction on their own. A number of physical-chemical treatment technologies are applicable at bathroom scale and can provide the necessary volume reduction, but only with a steady supply of chemicals and often with high demand for energy and maintenance. Electrochemical processes is a recent, but rapidly growing field, which could give rise to exciting technologies at bathroom scale, although energy production might only be interesting for niche applications. The review includes a qualitative assessment of all unit processes. A quantitative comparison of treatment performance was not the goal of the study and could anyway only be done for complete treatment trains. An important next step in urine technology research and development will be the combination of unit processes to set up and test robust treatment trains. We hope that the present review will help guide these efforts to accelerate the development towards a mature technology with pilot scale and eventually full-scale implementations.
Larsen, T. A.; Riechmann, M. E.; Udert, K. M. (2021) State of the art of urine treatment technologies: a critical review., Water Research X, 13, 100114 (20 pp.), doi:10.1016/j.wroa.2021.100114, Institutional Repository

Institutional barriers to on-site alternative water systems: a conceptual framework and systematic analysis of the literature

Scientists are increasingly exploring on-site water systems to supplement conventional centralized water and wastewater infrastructure. While major technological advancements have been achieved, we still lack a systematic view on the non-technical, or institutional, elements that constitute important barriers to the uptake of on-site urban water management systems. This paper presents a conceptual framework distinguishing between institutional barriers in six key dimensions: Equity, Knowledge and Capabilities, Financial Investment, Legal and Regulatory Frameworks, Legitimacy, and Market Structures. The analysis of the existing literature covering these barriers is translated into a typology of the socio-technical complexity of different types of alternative water systems (e.g., non-potable reuse, rainwater systems, and nutrient recovery). Findings show that socio-technical complexity increases with the pollution load in the source water, correlating to potential health risk, and the number of sectors involved in the value chain of an alternative water system. For example, greywater reuse for toilet flushing might have systematically less complex institutional barriers than source separation for agricultural reuse. This study provides practitioners with easily accessible means of understanding non-technical barriers for various types of on-site reuse systems and provides researchers with a conceptual framework for capturing socio-technical complexity in the adoption of alternative water systems.
Hacker, M. E.; Binz, C. (2021) Institutional barriers to on-site alternative water systems: a conceptual framework and systematic analysis of the literature, Environmental Science and Technology, 55(12), 8267-8277, doi:10.1021/acs.est.0c07947, Institutional Repository

The potential contribution of urine source separation to the SDG agenda - a review of the progress so far and future development options

Sanitation and wastewater management are highly relevant for reaching a number of interconnected sustainable development goals (SDGs), especially SDG 6, the provision of safe drinking water and adequate sanitation for all as well as protection of water resources against pollution, and SDG 14.1, reducing nutrient emissions to the marine environment. Recent evidence increasingly shows that conventional sewer-based wastewater management will not be able to reach these targets. Rather than further optimizing and diffusing this ageing infrastructure paradigm, radical innovations like urine source separation technologies could help to leapfrog towards faster achievement of the SDGs. The technology would simplify on-site sanitation and develop a closed-loop nutrient cycle, thereby allowing for exceptionally high nutrient removal from wastewater and direct reuse in agriculture from the first day of implementation. Radical innovations, however, need decades to materialize. Based on a review of relevant academic and grey literature, we show how the past three decades of development of urine source separation have brought breakthroughs in toilet design and treatment processes, enabling the technology's value chain to reach the brink of maturity. In a short outlook, we discuss how the technology may reach global diffusion over the next decade, with the main remaining challenges relating to the creation of mass-markets for urine-diverting toilets, automation and mass-production of treatment systems, and the legitimation of fertilizer produced from urine in the agricultural sector.
Larsen, T. A.; Gruendl, H.; Binz, C. (2021) The potential contribution of urine source separation to the SDG agenda - a review of the progress so far and future development options, Environmental Science: Water Research and Technology, 7(7), 1161-1176, doi:10.1039/D0EW01064B, Institutional Repository

Making waves: why water reuse frameworks need to co-evolve with emerging small-scale technologies

Novel technologies allow to reuse or recycle water for on-site applications such as toilet flushing, showering, or hand washing at the household- or building-scale. Many of these technologies have now reached technology readiness levels that require for verification and validation testing in the field. Results from such field tests of decentralized water reuse systems have been published over the past few years, and observed performance is often compared to quality targets from water reuse frameworks (WRFs). An inspection of ten recent journal publications reveals that targets from WRFs are often misinterpreted, and the emphasis of these publications is too often on demonstrating successful aspects of the technologies rather than critically evaluating the quality of the produced water. We hypothesize that some of these misinterpretations are due to ambiguous definition of scopes of WRFs (e.g., "unrestricted urban reuse") and unclear applicability for novel recycling systems that treat the water for applications that go beyond the reuse scopes defined in current WRFs. Additional challenges are linked to the verification of WRF quality targets in small-scale and decentralized systems under economic and organizational constraints. Current WRFs are not suitable for all possible reuse cases, and there is need for a critical discussion of quality targets and associated monitoring methods. As the scope of water reuse has expanded greatly over the past years, WRFs need to address new applications and advances in technology, including in monitoring capacities.
Reynaert, E.; Hess, A.; Morgenroth, E. (2021) Making waves: why water reuse frameworks need to co-evolve with emerging small-scale technologies, Water Research X, 11, 100094 (5 pp.), doi:10.1016/j.wroa.2021.100094, Institutional Repository

Ex-ante quantification of nutrient, total solids, and water flows in sanitation systems

To prioritise sustainable sanitation systems in strategic sanitation planning, indicators such as local appropriateness or resource recovery have to be known at the pre-planning phase. The quantification of resource recovery remains a challenge because existing substance flow models require large amounts of input data and can therefore only be applied for a few options at a time for which implementation examples exist. This paper aims to answer two questions: How can we predict resource recovery and losses of sanitation systems ex-ante at the pre-planning phase? And how can we do this efficiently to consider the entire sanitation system option space? The approach builds on an existing model to create all valid sanitation systems from a set of conventional and emerging technologies and to evaluate their appropriateness for a given application case. It complements the previous model with a Substance Flow Model (SFM) and with transfer coefficients from a technology library to quantify nutrients (phosphorus and nitrogen), total solids (as an indicator for energy and organics), and water flows in sanitation systems ex ante. The transfer coefficients are based on literature data and expert judgement. Uncertainties resulting from the variability of literature data or ignorance of experts are explicitly considered, allowing to assess the robustness of the model output. Any (future) technologies or additional products can easily be added to the library. The model is illustrated with a small didactic example showing how 12 valid system configurations are generated from a few technologies, and how substance flows, recovery ratios, and losses to soil, air, and water are quantified considering uncertainties. The recovery ratios vary between 0 and 28% for phosphorus, 0–10% for nitrogen, 0–26% for total solids, and 0–12% for water. The uncertainties reflect the high variability of the literature data but are comparable to those obtained in studies using a conventional post-ante material flow analysis (generally about 30% variability at the scale of a an urban area). Because the model is fully automated and based on literature data, it can be applied ex-ante to a large and diverse set of possible sanitation systems as shown with a real application case. From the 41 technologies available in the library, 101,548 systems are generated and substance flows are modelled. The resulting recovery ratios range from nothing to almost 100%. The two examples also show that recovery depend on technology interactions and has therefore to be assessed for all possible system configurations and not at the single technology level only. The examples also show that there exist trade-offs among different types of reuse (e.g. energy versus nutrients) or different sustainability indicators (e.g. local appropriateness versus resource recovery). These results show that there is a need for such an automated and generic approach that provides recovery data for all system configurations already at the pre-planning phase. The approach presented enables to integrate transparently the best available knowledge for a growing number of sanitation technologies into a planning process. The resulting resource recovery and loss ratios can be used to prioritise resource efficient systems in sanitation planning, either for the pre-selection or the detailed evaluation of options using e.g. MCDA. The results can also be used to guide future development of technology and system innovations. As resource recovery becomes more relevant and novel sanitation technologies and system options emerge, the approach presents itself as a useful tool for strategic sanitation planning in line with the Sustainable Development Goals (SDGs).
Spuhler, D.; Scheidegger, A.; Maurer, M. (2021) Ex-ante quantification of nutrient, total solids, and water flows in sanitation systems, Journal of Environmental Management, 280, 111785 (17 pp.), doi:10.1016/j.jenvman.2020.111785, Institutional Repository

Influence of intermittent flow on removal of organics in a biological activated carbon filter (BAC) used as post-treatment for greywater

Highly variable flow has to be expected in decentralized greywater treatment and can lead to intermittent operation of the treatment system. However, few studies have addressed the influence of variable flow on the treatment performance of a biological activated carbon filter (BAC). In this study, we investigated the influence of intermittent flow using small-scale BAC columns, which treat greywater as a second treatment step following a membrane bioreactor (MBR). Three operating strategies to respond to variable flow were evaluated. The activated carbon was characterized before and after the experiments in terms of biological activity and sorption capacity. The performance of the BAC filters was assessed based on total organic carbon (TOC) removal, TOC fractions and growth potential. No significant differences were observed between constant flow compared to on-off operation with intermittent flow over the range of tested influent concentrations. Peaks with high TOC during 24 h periods were attenuated by sorption and biological degradation. Adsorbed TOC was released after switching back to normal concentrations for influent concentrations more than 5 times higher than usually observed, the BAC functioned as a temporary sink. In line with these results, the high influent TOC values led to increased biological activity in the filter but did not influence the sorption capacity. The experiments showed that intermittent flow does not negatively impact the performance of a BAC and that there is no need for additional equalization tanks to buffer the variable flow, for example in household-scale greywater treatment.
Hess, A.; Bettex, C.; Morgenroth, E. (2020) Influence of intermittent flow on removal of organics in a biological activated carbon filter (BAC) used as post-treatment for greywater, Water Research X, 9, 100078 (10 pp.), doi:10.1016/j.wroa.2020.100078, Institutional Repository

A research agenda for the future of urban water management: exploring the potential of non-grid, small-grid, and hybrid solutions

Recent developments in high- and middle-income countries have exhibited a shift from conventional urban water systems to alternative solutions that are more diverse in source separation, decentralization, and modularization. These solutions include non-grid, small-grid, and hybrid systems to address such pressing global challenges as climate change, eutrophication, and rapid urbanization. They close loops, recover valuable resources, and adapt quickly to changing boundary conditions such as population size. Moving to such alternative solutions requires both technical and social innovations to co-evolve over time into integrated socio-technical urban water systems. Current implementations of alternative systems in high- and middle-income countries are promising, but they also underline the need for research questions to be addressed from technical, social, and transformative perspectives. Future research should apply a transdisciplinary research approach through socio-technical "lighthouse" projects that apply alternative urban water systems at scale. Such research should leverage experience from lighthouse projects in a range of socio-economic contexts, identify their potentials and limitations from an integrated perspective, and share their successes and failures across the urban water sector.
Hoffmann, S.; Feldmann, U.; Bach, P. M.; Binz, C.; Farrelly, M.; Frantzeskaki, N.; Hiessl, H.; Inauen, J.; Larsen, T. A.; Lienert, J.; Londong, J.; Lüthi, C.; Maurer, M.; Mitchell, C.; Morgenroth, E.; Nelson, K. L.; Scholten, L.; Truffer, B.; Udert, K. M. (2020) A research agenda for the future of urban water management: exploring the potential of non-grid, small-grid, and hybrid solutions, Environmental Science and Technology, 54(9), 5312-5322, doi:10.1021/acs.est.9b05222, Institutional Repository

Urine source separation for global nutrient management

The sewer-based paradigm for wastewater management at the global scale is not successful neither from a humanitarian nor from an environmental perspective. The systems are too expensive for the largest part of the global population. Source separation and resource recovery offer an alternative for sanitation and water pollution control. This chapter illustrates the importance but also the challenges of urine source separation for efficient nutrient removal and recovery.
Larsen, T. A. (2020) Urine source separation for global nutrient management, In: O’Bannon, D. J. (Eds.), Women in water quality. Investigations by prominent female engineers, 99-111, doi:10.1007/978-3-030-17819-2_6, Institutional Repository

Policy instrument mixes for operating modular technology within hybrid water systems

Water systems are experiencing dynamic societal demands and extreme environmental changes. The integration of modular water systems into existing centralized infrastructures, creating hybrid systems, could mitigate these challenges by enabling more resilient water management. However, the existence of technological alternatives has not changed the continuous reliance on centralized water infrastructure. Supportive policy instruments are key to foster the operation of modular technology within hybrid water systems. This article focuses on the role of substantive and procedural policy instruments for the successful operation of modular water systems within a hybrid water infrastructure. Based on Qualitative Comparative Analysis (QCA), we can confirm the claim in the literature that relying on regulatory instruments is relevant for operating modular technology within hybrid systems. However, we also find combinations of policy instruments where regulatory instruments do not matter. Furthermore, we find that procedural instruments emphasizing stakeholder participation interplay with different substantive policy instruments to support the successful operation of modular systems.
Pakizer, K.; Fischer, M.; Lieberherr, E. (2020) Policy instrument mixes for operating modular technology within hybrid water systems, Environmental Science and Policy, 105, 120-133, doi:10.1016/j.envsci.2019.12.009, Institutional Repository

The toilet revolution: improved water pollution control and reuse of wastewater in urban slums and in modern cities

With two new toilet systems, one for urban slums and the other for modern cities, we can at the same time improve water pollution control and further the economic reuse of wastewater. For urban slums, the Blue Diversion Toilet is an appealing, affordable and safe technical solution. It is designed for industrialised manufacturing and implements a sustainable sanitation value chain with total resource recovery and zero discharge. The important concept of the toilet is urine source separation. This concept that can also revolutionise wastewater management in the modern cities of industrialised and fast industrialising countries. With the new urine-separating toilet Save! this toilet revolution can spread on a global scale, offering a cost-efficient measure to help save surface water from eutrophication, make reuse of wastewater easier and cheaper and – as a side effect - provide fertiliser for urban and rural agriculture.
Gründl, H.; Larsen, T. A. (2019) The toilet revolution: improved water pollution control and reuse of wastewater in urban slums and in modern cities, World Architecture, 36-39, Institutional Repository

Sanierungsfall Abwassersystem

Mit einem Wiederbeschaffungswert von 230 Milliarden Franken zählt die Wasserversorgung und Abwasserentsorgung in der Schweiz zu den wertvollsten Infrastrukturbauten. Alternde Leitungen, steigende Bevölkerungszahlen und zunehmende Urbanisierung verlangen in den nächsten 30 Jahren Investitionen von insgesamt 130 Milliarden Franken. Auf globaler Ebene schätzt die OECD die Investitionen in die Siedlungswasserwirtschaft auf jährlich 900 Milliarden Franken. Dieser hohe Investitionsbedarf und der global steigende Druck, neue Ansätze zu finden, bieten einen Spielraum für innovative Lösungen. Die Schweiz hat mit ihrer Spitzenforschung in diesem Bereich und dem aktuellen Bedarf an Infrastrukturerneuerung ein ungenutztes «Lead-Market»-Potenzial. Dazu braucht es aber ein gesamtschweizerisches Impulsprogram, das die fragmentierten Infrastrukturentscheide der Gemeinden koordiniert.
Maurer, M.; Hoffmann, S. (2019) Sanierungsfall Abwassersystem, Volkswirtschaft, 89(6), 12-15, Institutional Repository

Beyond signal quality: the value of unmaintained pH, dissolved oxygen, and oxidation-reduction potential sensors for remote performance monitoring of on-site sequencing batch reactors

Sensor maintenance is time-consuming and is a bottleneck for monitoring on-site wastewater treatment systems. Hence, we compare maintained and unmaintained sensors to monitor the biological performance of a small-scale sequencing batch reactor (SBR). The sensor types are ion-selective pH, optical dissolved oxygen (DO), and oxidation-reduction potential (ORP) with platinum electrode. We created soft sensors using engineered features: ammonium valley for pH, oxidation ramp for DO, and nitrite ramp for the ORP. Four soft sensors based on unmaintained pH sensors correctly identified the completion of the ammonium oxidation (89–91 out of 107 cycles), about as many times as soft sensors based on a maintained pH sensor (91 out of 107 cycles). In contrast, the DO soft sensor using data from a maintained sensor showed slightly better (89 out of 96 cycles) detection performance than that using data from two unmaintained sensors (77, respectively 82 out of 96 correct). Furthermore, the DO soft sensor using maintained data is much less sensitive to the optimisation of cut-off frequency and slope tolerance than the soft sensor using unmaintained data. The nitrite ramp provided no useful information on the state of nitrite oxidation, so no comparison of maintained and unmaintained ORP sensors was possible in this case. We identified two hurdles when designing soft sensors for unmaintained sensors: i) Sensors’ type- and design-specific deterioration affects performance. ii) Feature engineering for soft sensors is sensor type specific, and the outcome is strongly influenced by operational parameters such as the aeration rate. In summary, the results with the provided soft sensors show that frequent sensor maintenance is not necessarily needed to monitor the performance of SBRs. Without sensor maintenance monitoring smalls-scale SBRs becomes practicable, which could improve the reliability of unstaffed on-site treatment systems substantially.
Schneider, M. Y.; Carbajal, J. P.; Furrer, V.; Sterkele, B.; Maurer, M.; Villez, K. (2019) Beyond signal quality: the value of unmaintained pH, dissolved oxygen, and oxidation-reduction potential sensors for remote performance monitoring of on-site sequencing batch reactors, Water Research, 161, 639-651, doi:10.1016/j.watres.2019.06.007, Institutional Repository

Stabilizing control of a urine nitrification process in the presence of sensor drift

Sensor drift is commonly observed across engineering disciplines, particularly in harsh media such as wastewater. In this study, a novel stabilizing controller for nitrification of high strength ammonia solutions is designed based on online signal derivatives. The controller uses the derivative of a drifting nitrite signal to determine if nitrite-oxidizing bacteria (NOB) are substrate limited or substrate inhibited. To ensure a meaningful interpretation of the derivative signal, the process is excited in a cyclic manner by repeatedly exposing the NOB to substrate-limited and substrate-inhibited conditions. The resulting control system successfully prevented nitrite accumulations for a period of 72 days in a laboratory-scale reactor. Slow disturbances in the form of feed composition changes and temperature changes were successfully handled by the controller while short-term temperature disturbances are shown to pose a challenge to the current version of this controller. Most importantly, we demonstrate that drift-tolerant control for the purpose of process stabilization can be achieved without sensor redundancy by combining deliberate input excitation, qualitative trend analysis, and coarse process knowledge.
Thürlimann, C. M.; Udert, K. M.; Morgenroth, E.; Villez, K. (2019) Stabilizing control of a urine nitrification process in the presence of sensor drift, Water Research, 165, 114958 (10 pp.), doi:10.1016/j.watres.2019.114958, Institutional Repository

A review of water-related serious games to specify use in environmental Multi-Criteria Decision Analysis

Serious games and gamification are nowadays pervasive. They are used to communicate about science and sometimes to involve citizens in science (e.g. citizen science). Concurrently, environmental decision analysis is challenged by the high cognitive load of the decision-making process and the possible biases threatening the rationality assumptions. Difficult decision-making processes can result in incomplete preference construction, and are generally limited to few participants. We reviewed 43 serious games and gamified applications related to water. We covered the broad diversity of serious games, which could be explained by the still unsettled terminology in the research area of gamification and serious gaming. We discuss how existing games could benefit early steps of Multi-Criteria Decision Analysis (MCDA), including problem structuring, stakeholder analysis, defining objectives, and exploring alternatives. We argue that no existing game allows for preference elicitation; one of the most challenging steps of MCDA. We propose many research opportunities for behavioral operational research.
Aubert, A. H.; Bauer, R.; Lienert, J. (2018) A review of water-related serious games to specify use in environmental Multi-Criteria Decision Analysis, Environmental Modelling and Software, 105, 64-78, doi:10.1016/j.envsoft.2018.03.023, Institutional Repository

Towards sustainable sanitation in an urbanising world

Urban sanitation in low‐ and middle‐income countries is at an inflection point. It is increasingly acknowledged that conventional sewer‐based sanitation cannot be the only solution for expanding urban areas. There are other objective reasons apart from the lack of capital. The lack of stable energy supplies, of spare parts and of human resources for reliable operation, and the increasing water scarcity are factors that seriously limit the expansion of centralised systems. This chapter argues that a new paradigm for urban sanitation is possible, if the heterogeneity within developing cities is reflected in the implementation of different sanitation systems, adapted to each urban context and integrated under one institutional roof. This new paradigm entails: (1) innovative management arrangements; (2) increased participation and the integration of individual, community and private sector initiatives; (3) thinking at scale to open new opportunities; (4) improved analysis of the situation and awareness raising. Moving beyond conventional approaches towards sustainable urbanisation needs to follow both a top‐down and a bottom‐up approach, with proper incentives and a variety of sanitation systems which, in a future perspective, will become part of the 'urban ecosystem'.
Reymond, P.; Renggli, S.; Lüthi, C. (2016) Towards sustainable sanitation in an urbanising world, In: Ergen, M. (Eds.), Sustainable urbanization, 115-134, doi:10.5772/63726, Institutional Repository

Emerging solutions to the water challenges of an urbanizing world

The top priorities for urban water sustainability include the provision of safe drinking water, wastewater handling for public health, and protection against flooding. However, rapidly aging infrastructure, population growth, and increasing urbanization call into question current urban water management strategies, especially in the fast-growing urban areas in Asia and Africa. We review innovative approaches in urban water management with the potential to provide locally adapted, resource-efficient alternative solutions. Promising examples include new concepts for stormwater drainage, increased water productivity, distributed or on-site treatment of wastewater, source separation of human waste, and institutional and organizational reforms. We conclude that there is an urgent need for major transdisciplinary efforts in research, policy, and practice to develop alternatives with implications for cities and aquatic ecosystems alike.
Larsen, T. A.; Hoffmann, S.; Lüthi, C.; Truffer, B.; Maurer, M. (2016) Emerging solutions to the water challenges of an urbanizing world, Science, 352(6288), 928-933, doi:10.1126/science.aad8641, Institutional Repository

To connect or not to connect? Modelling the optimal degree of centralisation for wastewater infrastructures

The strong reliance of most utility services on centralised network infrastructures is becoming increasingly challenged by new technological advances in decentralised alternatives. However, not enough effort has been made to develop planning tools designed to address the implications of these new opportunities and to determine the optimal degree of centralisation of these infrastructures. We introduce a planning tool for sustainable network infrastructure planning (SNIP), a two-step techno-economic heuristic modelling approach based on shortest path-finding and hierarchical-agglomerative clustering algorithms to determine the optimal degree of centralisation in the field of wastewater management. This SNIP model optimises the distribution of wastewater treatment plants and the sewer network outlay relative to several cost and sewer-design parameters. Moreover, it allows us to construct alternative optimal wastewater system designs taking into account topography, economies of scale as well as the full size range of wastewater treatment plants. We quantify and confirm that the optimal degree of centralisation decreases with increasing terrain complexity and settlement dispersion while showing that the effect of the latter exceeds that of topography. Case study results for a Swiss community indicate that the calculated optimal degree of centralisation is substantially lower than the current level.
Eggimann, S.; Truffer, B.; Maurer, M. (2015) To connect or not to connect? Modelling the optimal degree of centralisation for wastewater infrastructures, Water Research, 84, 218-231, doi:10.1016/j.watres.2015.07.004, Institutional Repository

Inter- and Transdisciplinarity

Leading inter- and transdisciplinary research: lessons from applying theories of change to a strategic research program

Theory of Change (ToC) has been promoted as a useful tool in sustainability research for visioning, planning, communication, monitoring, evaluation and learning. It involves a mapping of steps towards a desired long-term goal supplemented with continuous reflection on how and why change is expected to happen in a particular context. However, there is limited reported experience with the development and application of ToCs in inter- and transdisciplinary research contexts. While some previous publications have focused on ex-post application, there has been little discussion about the process of developing and using ToCs in strategic planning and monitoring in large inter- and transdisciplinary research programs. This article reports challenges and lessons learned from the experience of developing and using ToCs in the inter- and transdisciplinary research program Wings (Water and sanitation innovations for non-grid solutions). Challenges include (1) managing time constraints, (2) balancing between concrete and abstract discussions, (3) ensuring diversity in group composition, (4) fluctuating between reservations and appreciation, and (5) fulfilling both service and science roles while leading the ToC process. The experience highlights the importance of alternating formal and informal interaction formats throughout the process, ensuring heterogenous group formation, involving early career scientists, being responsive to emergent needs and making the added value of developing and using ToCs explicit and tangible for all participants. Although these lessons are mainly derived from developing ToCs within the interdisciplinary program team, they can support other programs in both their inter- and transdisciplinary research endeavors.
Deutsch, L.; Belcher, B.; Claus, R.; Hoffmann, S. (2021) Leading inter- and transdisciplinary research: lessons from applying theories of change to a strategic research program, Environmental Science and Policy, 120, 29-41, doi:10.1016/j.envsci.2021.02.009, Institutional Repository

Exploring Julie Thompson Klein's framework for analysis of boundary work

Julie Thompson Klein’s contributions to interdisciplinary and transdisciplinary research have enriched the way collaboration is discussed and handled by introducing concepts of boundary work and boundary crossing from the field of Science and Technology Studies. In recent years, she has been integrating those concepts into crossdisciplinarity, an effort culminating in the development of a framework for a forthcoming book (Beyond Interdisciplinarity: Boundary Work, Collaboration, and Communication in the 21st Century). With her permission, we have used an earlier version of her framework to analyze boundary work and boundary crossing in transdisciplinary sustainable water management projects in Australia and Switzerland. The aim of using the framework has been twofold: to explore and assess the heuristic value of the framework, i.e. how it improves our conceptualization of boundary work in the two projects, and to examine the framework itself, i.e. whether some of the seven concepts involved are hard to work with or should be further developed.
Pohl, C.; Fam, D.; Hoffmann, S.; Mitchell, C. (2019) Exploring Julie Thompson Klein's framework for analysis of boundary work, Issues in Interdisciplinary Studies, 37(2), 62-89, Institutional Repository

Linking transdisciplinary research projects with science and practice at large: introducing insights from knowledge utilization

Recent empirical studies show a persistent gap between 'socially robust' knowledge produced by transdisciplinary research projects and its ability to promote change on a large scale. Current discourses about the 'project-to-science-and-practice-at-large gap' have focused mainly on exploring various conditions that need to be fulfilled to produce 'socially robust' knowledge. Yet, those discourses have rarely built on the broader literature of knowledge utilization, which Greenhalgh and Wieringa (2011) emphasize acknowledges 'the fundamentally social ways in which knowledge emerges, circulates, and gets applied in practice.' Their insights are helpful in advancing our understanding of why transdisciplinary research projects do or do not contribute to sustainability on a large scale. Expanding Jahn et al. (2012)'s model of transdisciplinary research, we present a revised conceptual model of an ideal-typical, interactive and iterative transdisciplinary research process that adds two new phases from the field of knowledge utilization to their original three-phase model and accounts for the social and relational nature of knowledge utilization. The revised model includes five phases through which transdisciplinary projects operate in different order: (i) defining sustainability problems, (ii) producing new knowledge, (iii) assessing new knowledge, (iv) disseminating new knowledge in realms of both science and practice and (v) using new knowledge in both realms.
Hoffmann, S.; Thompson Klein, J.; Pohl, C. (2019) Linking transdisciplinary research projects with science and practice at large: introducing insights from knowledge utilization, Environmental Science and Policy, 102, 36-42, doi:10.1016/j.envsci.2019.08.011, Institutional Repository

EVOLvINC: evaluating knowledge integration capacity in multistakeholder governance

Research and policy processes in many fields, such as sustainability and health, are increasingly relying on transdisciplinary cooperation among a multitude of governmental, nongovernmental, and private actors from local to global levels. In the absence of hierarchical chains of command, multistakeholder governance may accommodate conflicting or diverse interests and facilitate collective action, but its effectiveness depends on its capacity to integrate systems, transformation, and target knowledge. Approaches to foster such governance are nascent and quickly evolving, and methodological standards to facilitate comparison and learning from best practice are needed. However, there is currently no evaluation approach that (i) comprehensively assesses the capacity for knowledge integration in multistakeholder governance, (ii) draws on the best available knowledge that is being developed in various fields, and (iii) combines a systematic and transferable methodological design with pragmatic feasibility.

We brought together 20 experts from institutions in nine countries, all working on evaluation approaches for collaborative science–policy initiatives. In a synthesis process that included a 2-day workshop and follow-up work among a core group of participants, we developed a tool for evaluating knowledge integration capacity in multistakeholder governance (EVOLvINC). Its 23 indicators incorporate previously defined criteria and components of transdisciplinary evaluations into a single, comprehensive framework that operationalizes the capacity for integrating systems, target, and transformation knowledge during an initiative’s (a) design and planning processes at the policy formulation stage, (b) organization and working processes at the implementation stage, and (c) sharing and learning processes at the evaluation stage of the policy cycle. EVOLvINC is (i) implemented through a questionnaire, (ii) builds on established indicators where possible, (iii) offers a consistent and transparent semiquantitative scoring and aggregation algorithm, and (iv) uses spider diagrams for visualizing results. The tool builds on experience and expertise from both the northern and southern hemispheres and was empirically validated with seven science–policy initiatives in six African and Asian countries.

As a generalized framework, EVOLvINC thus enables a structured reflection on the capacity of multistakeholder governance processes to foster knowledge integration. Its emphasis on dialog and exploration allows adaptation to contextual specificities, highlights relative strengths and weaknesses, and suggests avenues for shaping multistakeholder governance toward mutual learning, capacity building, and strengthened networks. The validation suggests that the adaptive capacity of multistakeholder governance could be best enhanced by considering systems characteristics at the policy formulation stage and fostering adaptive and generic learning at the evaluation stage of the policy cycle.
Hitziger, M.; Aragrande, M.; Berezowski, J. A.; Canali, M.; Del Rio Vilas, V.; Hoffmann, S.; Igrejas, G.; Keune, H.; Lux, A.; Bruce, M.; Palenberg, M. A.; Pohl, C.; Radeski, M.; Richter, I.; Robledo Abad, C.; Salerno, R. H.; Savic, S.; Schirmer, J.; Vogler, B. R.; Rüegg, S. R. (2019) EVOLvINC: evaluating knowledge integration capacity in multistakeholder governance, Ecology and Society, 24(2), 36 (16 pp.), doi:10.5751/ES-10935-240236, Institutional Repository

Indicators for measuring the contributions of individual knowledge brokers

An increasing number of knowledge brokers work at the interface between research, policy and practice. Their function is to facilitate processes to foster mutual learning among research, policy and practice. For some knowledge brokers, practical methodologies to assess the quality of their work is an important concern. While frameworks exist for assessing research impact at the level of a project or program, few are available for assessing contributions of individual knowledge brokers. In response to this, we have compiled a set of indicators to measure the quantity and quality of the contributions of individual knowledge brokers to projects, programs or platforms at the interface between research, policy and practice. The set is based on a review of the literature and the experience of a group of knowledge brokers active in water research and management in Switzerland, including the co-authors of this article. The set can be used by knowledge brokers to identify ways to improve the effectiveness of their practices and to demonstrate the benefit of their work to their employers and other stakeholders. Our approach is flexible enough that it can be applied where there are limited resources available for assessment.
Maag, S.; Alexander, T. J.; Kase, R.; Hoffmann, S. (2018) Indicators for measuring the contributions of individual knowledge brokers, Environmental Science and Policy, 89, 1-9, doi:10.1016/j.envsci.2018.06.002, Institutional Repository

Case Studies

Potenzial dezentraler Abwassersysteme

Werterhalt und Bewirtschaftung von Kanalisation und ARA können kleine Gemeinden vor Herausforderungen stellen. Es gibt Alternativen, aber lohnen sich diese? Zwei Gemeinden wurden bei der strategischen Planung für ihr neues Abwassersystem unterstützt. Viele Ziele wurden als entscheidungsrelevant identifiziert, insbesondere Umweltschutzziele. Es zeigte sich, dass dezentrale Technologien mit Stoffstromseparierung die Anforderungen häufig besser erfüllen können als konventionelle Abwassersysteme.
Beutler, P.; Larsen, T. A.; Maurer, M.; Staufer, P.; Lienert, J. (2021) Potenzial dezentraler Abwassersysteme, Aqua & Gas, 101(1), 66-75, Institutional Repository

Navigating institutional complexity in socio-technical transitions

Transitions from one socio-technical regime configuration to another entail long phases of institutional complexity, where two or more field logics co-exist in a sector and induce incompatibilities and frictions. This paper presents a dynamic phase model, which characterizes the types of institutional complexity that may build up and settle across various phases of a transition, illustrated with a case study from the diffusion of onsite water reuse in San Francisco. Results from semi-structured expert interviews and a focus group demonstrate that different forms of institutional complexity may follow each other in a transition trajectory and that formidable strategic agency is needed by the actors in a field in navigating prolonged phases of competing cultural demands. Gaining a more balanced perspective of both organizational and field-level reconfigurations may help better explain why transitions succeed in some places and fail in others.
Hacker, M. E.; Binz, C. (2021) Navigating institutional complexity in socio-technical transitions, Environmental Innovation and Societal Transitions, 40, 367-381, doi:10.1016/j.eist.2021.09.003, Institutional Repository

Governance of small-scale sanitation in India. Institutional analysis and policy recommendations. Small‐scale sanitation scaling‐up (4S) - project report vol. II

Small-scale sanitation (SSS) systems are making an increasingly important contribution to urban sanitation coverage in India, alongside large-scale sewage (wastewater) treatment plants (STPs) and the management of faecal sludge and septage from non-sewered sanitation systems. Such systems consist of small-scale sewerage networks and STPs. They represent a wastewater management solution for buildings and neighbourhoods in rapidly growing cities, especially where a connection to the centralised sewerage network is not feasible in the short to medium term. SSS systems can be implemented incrementally and flexibly, offering significant potential for cost-effective local wastewater treatment and reuse.
Ulrich, L.; Reymond, P.; Chandragiri, R.; Lüthi, C. (2021) Governance of small-scale sanitation in India. Institutional analysis and policy recommendations. Small‐scale sanitation scaling‐up (4S) - project report vol. II, 162 p, Institutional Repository

Innovation for improved hand hygiene: field testing the Autarky handwashing station in collaboration with informal settlement residents in Durban, South Africa

Safe and accessible water services for hand hygiene are critical to human health and well-being. However, access to handwashing facilities is limited in cities in the Global South, where rapid urbanisation, service backlogs, lack of infrastructure and capacity, and water scarcity impact on the ability of local governments to provide them. Community participation and the co-production of knowledge in the development of innovative technologies, which are aligned with Water, Sanitation and Hygiene (WASH) principles, can lead to more sustainable and socially-acceptable hand hygiene systems. This paper presents the outcomes of the testing of the Autarky handwashing station, a technology that provides onsite treatment and recycling of handwashing water, in an informal settlement in Durban, South Africa. The transdisciplinary research approach adopted enabled the participation of multiple stakeholders with different knowledge systems in the framing, testing and evaluation of the system. The process of co-producing knowledge, as well as the outcomes of the testing, namely high levels of functionality and social acceptability of the technology, supported the WASH principles. The evaluation revealed that the Autarky handwashing station is a niche intervention that improved access to safe and appealing handwashing facilities in an informal settlement. Its novel design, socially desirable features, reliability and ability to save water increased its acceptance in the community. The testing of the system in a real-world context revealed the value of including communities in knowledge production processes for technology innovation. Further work is required to ensure that real-time monitoring of system function is feasible before such systems can be implemented at larger scale.
Sutherland, C.; Reynaert, E.; Sindall, R. C.; Riechmann, M. E.; Magwaza, F.; Lienert, J.; Buthelezi, S.; Khumalo, D.; Dhlamini, S.; Morgenroth, E.; Udert, K. M. (2021) Innovation for improved hand hygiene: field testing the Autarky handwashing station in collaboration with informal settlement residents in Durban, South Africa, Science of the Total Environment, 796, 149024 (13 pp.), doi:10.1016/j.scitotenv.2021.149024, Institutional Repository

Socio-technical analysis of a sanitation innovation in a peri-urban household in Durban, South Africa

The provision of water and sanitation for all that is safe, dignified, reliable, affordable and sustainable is a major global challenge. While centralized sewer-based sanitation systems remain the dominant approach to providing sanitation, the benefits of non-sewered onsite sanitation systems are increasingly being recognised. This paper presents the outcomes of the testing of the Blue Diversion Autarky Toilet (BDAT), a sanitation system providing hygiene and dignity without relying on water and wastewater infrastructure, in a peri-urban household in Durban, South Africa. The BDAT was used by a single household as their only form of sanitation during three months of technical and social testing. An analysis based on technical data in combination with interpretive, qualitative research methods revealed that the BDAT functioned well and achieved high levels of social acceptance in the test household. The flushing, cleanliness and odour-free nature of the sanitation technology, its functionality, the household's previous sanitation experience, and their experience with and understanding of water scarcity, were the main factors underpinning their positive response to this innovation in sanitation. The testing process resulted in broader developmental benefits for the household, including improved basic services due to the upgrading of the electrical and existing sanitation system, social learning, and improved relationships between household members and the local state. A transdisciplinary research process, which emerged through the assessment, enabled the integration of different forms of knowledge from multiple actors to address the complexity of problems related to the development of socially just sanitation. The benefit of engaging with societal actors in sanitation innovation and assessing its outcomes using both the technical and social sciences is evident in this paper.
Sutherland, C.; Reynaert, E.; Dhlamini, S.; Magwaza, F.; Lienert, J.; Riechmann, M. E.; Buthelezi, S.; Khumalo, D.; Morgenroth, E.; Udert, K. M.; Sindall, R. C. (2021) Socio-technical analysis of a sanitation innovation in a peri-urban household in Durban, South Africa, Science of the Total Environment, 755, 143284 (12 pp.), doi:10.1016/j.scitotenv.2020.143284, Institutional Repository

Water Hub im NEST-Gebäude. Eine Plattform zum Testen von innovativen ressourcenorientierten Sanitärsystemen

Mit innovativen Technologien werden im Water Hub unter realen Bedingungen Ressourcen aus dem Abwasser gewonnen und Kreisläufe geschlossen. Die Forschung in diesem Living Lab erlaubt es, praxisnahe Erfahrungen zu machen, Schwachstellen schnell zu identifizieren und das System zu optimieren. Bei der Implementierung dieser dezentralen Technologien spielen die lokalen Herausforderungen und Begebenheiten stets eine wichtige Rolle.
Doll, C.; Larsen, T. A.; Strande, L.; Udert, K. M.; Morgenroth, E. (2020) Water Hub im NEST-Gebäude. Eine Plattform zum Testen von innovativen ressourcenorientierten Sanitärsystemen, Aqua & Gas, 100(2), 52-57, Institutional Repository

Social network analysis for water, sanitation, and hygiene (WASH): application in governance of decentralized wastewater treatment in India using a novel validation methodology

Social network analysis (SNA) is a versatile and increasingly popular methodological tool to understand structures of relationships between actors involved in governance situations. Given the complexity of the set of stakeholders involved in the governance of Water, Sanitation and Hygiene (WASH) and the diversity of their interests, this article proposes SNA to the WASH sector. The use of SNA as an appropriate diagnostic tool for planning Citywide Inclusive Sanitation is explored. Missing data is a major problem for SNA in the studies of governance situations, especially in low- and middle-income countries. Therefore, a novel validation methodology for incomplete SNA data, relying on information from internal and external experts is proposed. SNA and the validation method is then applied to study the governance of decentralized wastewater treatment in four cities of India. The results corroborate key differences between mega and secondary cities in terms of institutions, community engagement and overall sanitation situation including aspects of decentralized wastewater treatment plants, based on the city types.
Narayan, A. S.; Fischer, M.; Lüthi, C. (2020) Social network analysis for water, sanitation, and hygiene (WASH): application in governance of decentralized wastewater treatment in India using a novel validation methodology, Frontiers in Environmental Science, 7, 198 (18 pp.), doi:10.3389/fenvs.2019.00198, Institutional Repository

Governance arrangements for the scaling up of small-scale wastewater treatment and reuse systems - lessons from India

Environmental pollution and increasing water scarcity are key features of the urban landscape of India today. The extension of centralized sewerage networks cannot keep up with city growth, and alternative sanitation systems are needed for citywide inclusive sanitation (CWIS). The government of India mandated larger buildings to be equipped with small-scale wastewater treatment plants (SSTP). This resulted in the emergence of a large number of technology and service providers, and in the implementation of thousands of private SSTPs. However, this quick scaling up was not accompanied by the development of appropriate governance arrangements. As a result, a significant proportion of SSTPs underperform and do not meet the effluent standards. Through a systematic analysis of governance arrangements around SSTPs, this contribution analyses the scaling up process of small-scale wastewater management and reuse at building level in India, in particular in the state of Karnataka and the city of Bengaluru. This paper identifies the gaps in this multi-level, polycentric governance framework and investigates which arrangements are needed to enable the performance of SSTPs on the ground and to create the necessary synergies between the relevant governmental agencies, the private sector and civil society. The scaling up of SSTPs in India mainly followed a market governance approach within a governance environment that is traditionally very hierarchical. The authors argue that hybrid governance arrangements, blending hierarchical, market and network governance are needed to foster market regulation and stakeholder coordination, and increase the performance of the sector. They conclude that an efficient governance of SSS requires the creation of dedicated SSS units at state and city level, and the development of an online platform collating all databases, streamlining and supporting processes from establishment to monitoring, and allowing meaningful collaboration between stakeholders. Through the case study of India, this paper contributes to understand the governance arrangements necessary for the successful scaling up of decentralized sanitation systems, and how to fulfill the potential of alternative solutions for sustainable urban water management. It contributes to governance studies by substantiating the concept of hybrid governance approach and proposing concrete measures to make it work for such distributed systems.
Reymond, P.; Chandragiri, R.; Ulrich, L. (2020) Governance arrangements for the scaling up of small-scale wastewater treatment and reuse systems - lessons from India, Frontiers in Environmental Science, 8, 72 (16 pp.), doi:10.3389/fenvs.2020.00072, Institutional Repository

Practical implementation of true on-site water recycling systems for hand washing and toilet flushing

On-site wastewater reuse can improve global access to clean water, sanitation and hygiene. We developed a treatment system (aerated bioreactor, ultrafiltration membrane, granular activated carbon and electrolysis for chlorine disinfection) that recycles hand washing and toilet flush water.
Three prototypes were field-tested in non-sewered areas, one in Switzerland (hand washing) and two in South Africa (hand washing, toilet flushing), over periods of 63, 74 and 94 days, respectively.
We demonstrated that the system is able to recycle sufficient quantities of safe and appealing hand washing and toilet flush water for domestic or public use in real-life applications. Chemical contaminants were effectively removed from the used water in all prototypes. Removal efficiencies were 99.7% for the chemical oxygen demand (COD), 98.5% for total nitrogen (TN) and 99.9% for phosphate in a prototype treating hand washing water, and 99.8% for COD, 95.7% for TN and 89.6% for phosphate in a prototype treating toilet flush water. While this system allowed for true recycling for the same application, most on-site wastewater reuse systems downcycle the treated water, i.e., reuse it for an application requiring lower water quality. An analysis of 18 selected wastewater reuse specifications revealed that at best these guidelines are only partially applicable to innovative recycling systems as they are focused on the downcycling of water to the environment (e.g., use for irrigation). We believe that a paradigm shift is necessary and advocate for the implementation of risk-based (and thus end-use dependent) system performance targets to evaluate water treatment systems, which recycle and not only downcycle water.
Reynaert, E.; Greenwood, E. E.; Ndwandwe, B.; Riechmann, M. E.; Sindall, R. C.; Udert, K. M.; Morgenroth, E. (2020) Practical implementation of true on-site water recycling systems for hand washing and toilet flushing, Water Research X, 7, 100051 (13 pp.), doi:10.1016/j.wroa.2020.100051, Institutional Repository
Beutler, P.; Lienert, J. (2020) Zukünftige Abwasserentsorgung im ländlichen Raum - Fallstudie 1. Technischer Bericht zur Entscheidungsunterstützung für die Gemeinde, 247 p, Institutional Repository

Anchoring innovations in oscillating domestic spaces: why sanitation service offerings fail in informal settlements

A persistent conundrum for practitioners and researchers in the development context is that, often, newly provided and improved basic services are not maintained by users despite seemingly superior functionality and user convenience. We argue that one major reason for this is an insufficient understanding of the context in which users have to manage their daily lives. We therefore propose an approach to analysing the embedding of basic services that focuses on the users' daily practices. We do so by borrowing insights from 'socio-technical transitions' and 'practice theory' in developing our concept of oscillating domestic spaces. The concept reflects the need for people to constantly respond to quickly changing and precarious circumstances by rearranging their daily practices in time and space and developing a multiplicity of alternative options and partial solutions. We illustrate the analytical approach in a case study of sanitation access in informal settlements of Nairobi, Kenya. The analysis shows how the introduction of a container-based toilet resulted in partial embedding. The innovation anchored to only a part of the oscillating domestic spaces and was in disarray with the needs of users most of the time. The conceptual approach contributes to the understanding about how users take part in sustainability transitions as well as the added value of the time-space dimension in analysing practices in highly complex contexts. We conclude by reflecting on the potential applicability of the analytical approach to transition cases in the Global North.
Cherunya, P. C.; Ahlborg, H.; Truffer, B. (2020) Anchoring innovations in oscillating domestic spaces: why sanitation service offerings fail in informal settlements, Research Policy, 49(1), 103841 (16 pp.), doi:10.1016/j.respol.2019.103841, Institutional Repository

Towards sustainable urban basic services in low-income countries: a Technological Innovation System analysis of sanitation value chains in Nairobi

The provision of basic services suffers from a multitude of sustainability challenges in many cities of low-income countries. Sanitation provision faces particular challenges in the form of environmental contamination, high costs, and large inequalities among urban residents. In recent years an increasing number of innovations in on-site systems have been developed, which have not yet evolved into fully functional alternatives to the existing regimes. We study three prominent recent on-site sanitation initiatives in informal settlements in Nairobi, Kenya that aimed at developing entire "sanitation value chains", which we conceptualize as an emerging Technological Innovation System (TIS). The analysis leads us to propose alternative governance modes for the TIS to overcome system failures such as capability, coordination and institutional barriers. Conceptually, the paper extends conventional TIS analyses towards entire value chains, enabling a wide range of transition processes to be addressed beyond informal settlements and low-income countries.
van Welie, M. J.; Truffer, B.; Yap, X.-S. (2019) Towards sustainable urban basic services in low-income countries: a Technological Innovation System analysis of sanitation value chains in Nairobi, Environmental Innovation and Societal Transitions, 33, 196-214, doi:10.1016/j.eist.2019.06.002, Institutional Repository

Shaping selection environments for industrial catch-up and sustainability transitions: a systemic perspective on endogenizing windows of opportunity

Transitioning economic sectors towards more sustainable futures is a major global challenge, in particular for non-OECD countries. Policymakers in these countries are confronted with a double challenge: how to implement cleaner technologies and infrastructures while at the same time promoting rapid industrial development. In catch-up studies, this trade-off has been increasingly interpreted as providing windows of opportunity for gaining strong leadership in new generations of cleantech industries. In this paper, we maintain that in order to specify how these windows of opportunity can be endogenized, a deeper understanding is needed about whether, how and by whom the directionality of innovation systems can be influenced. For this purpose, we propose an analytical approach that draws on the technological innovation system framework extending the current understanding of directionality in two ways: first, we complement the prevalent top-down perspective with a bottom-up view exemplified by the institutional entrepreneurship literature. Second, we posit that the focus has to be shifted from the manufacturing of single technologies to the transformation of entire socio-technical systems. The presented framework is validated by a case study on recent shifts in the dominant technology in China's urban water management sector. Major changes in the country's sectoral selection environment led membrane bioreactor technology to become the dominant design in urban water management - a development that is unmatched in any other country in the world. Owing to these transformations, China's technology firms outcompete multinational players and therefore they show strong potentials for industrial leapfrogging. However, although the promise to solve environmental problems played a decisive role in the shaping of the selection environment, it remains unclear whether the observed transformation leads the way to a more sustainable sector structure in the longer run. The case, however, still enables us to specify how windows of opportunity can be endogenized through the interplay of different actors trying to shape different layers of the selection environment in a specific sector.
Yap, X.-S.; Truffer, B. (2019) Shaping selection environments for industrial catch-up and sustainability transitions: a systemic perspective on endogenizing windows of opportunity, Research Policy, 48, 1030-1047, doi:10.1016/j.respol.2018.10.002, Institutional Repository

Screening European market potentials for small modular wastewater treatment systems – an inroad to sustainability transitions in urban water management?

Urban water management represents a core economic sector exposed to global water-related challenges. Recently, small modular system configurations have been identified to enable a potential sustainability transition in this lasting and rather conservative sector. The identification of current market potentials of decentralised wastewater treatment is a first step to assess whether decentralised treatment technologies could potentially be deployed on a larger scale in Europe, which would allow current decentralised wastewater treatment technologies to develop and mature. The paper elaborates a method to assess the market potential for decentralised wastewater treatment systems by starting from a raster-based geospatial modelling framework, to determine the optimal degrees of centralisation for the case of Switzerland. The resulting market potential is shown to be twenty times higher than the current market share of decentralised systems. In order to extrapolate these findings to other countries, the calculated optimal degrees of centralisation were correlated with different spatial density measures to determine a reliable and widely available proxy: population density. Based on this indicator, the European market potentials for decentralised treatment systems are estimated to be about 100,000 units per annum serving around 35 million population equivalents. The paper concludes by discussing implications for future sustainability transitions in urban water management by large-scale installation of small modular wastewater treatment systems.
Eggimann, S.; Truffer, B.; Feldmann, U.; Maurer, M. (2018) Screening European market potentials for small modular wastewater treatment systems – an inroad to sustainability transitions in urban water management?, Land Use Policy, 78, 711-725, doi:10.1016/j.landusepol.2018.07.031, Institutional Repository

Analysing transition pathways in developing cities: the case of Nairobi's splintered sanitation regime

Today's rapid global urbanization highlights the need for long-term transformations of basic service sectors in developing cities in order to improve the livelihoods of the urban poor. Sustainability transitions frameworks have proven fruitful for addressing these sort of challenges. However, they have been at pains so far in accounting for the heterogeneity and complexities that typically characterize informal settlements in the Global South. We therefore propose a conceptual framework that extends the conventional analysis of socio-technical regimes by distinguishing the two levels of sectoral regime and service regime. Challenges for sustainability transitions may then be identified by missing alignments within and among the two regime levels. The framework is applied to the sanitation sector of Nairobi, Kenya, a city experiencing rapid population growth and a highly uneven provision of basic services. Drawing on a set of 152 in-depth interviews, observations, and five focus group discussions, the paper reconstructs the prevailing service regimes and shows how they suffer from misalignments and dysfunctionalities creating all sorts of problems at a sectoral level. We conclude that Nairobi's sanitation sector can best be characterized as representing a splintered regime. The paper concludes with a discussion of how the new conceptualization of socio-technical regimes suggests some new sustainable transition pathways and how this framework might also be instructive for transition challenges in cities of the Global North.
van Welie, M. J.; Cherunya, P. C.; Truffer, B.; Murphy, J. T. (2018) Analysing transition pathways in developing cities: the case of Nairobi's splintered sanitation regime, Technological Forecasting and Social Change, 137, 259-271, doi:10.1016/j.techfore.2018.07.059, Institutional Repository

Path creation as a process of resource alignment and anchoring: industry formation for on-site water recycling in Beijing

Where and how new industrial paths emerge are much debated questions in economic geography, especially in light of the recent evolutionary turn. This article contributes to the ongoing debate on path creation with a new analytical framework that specifies the formation of generic resources in embryonic industries. It suggests that path creation processes are not only conditioned by preexisting regional capabilities and technological relatedness but also by the way firm and nonfirm actors mobilize and anchor key resources for industry formation. Our framework elaborates on the early industry development phase, extending the focus on regional knowledge spillovers in evolutionary economic geography (EEG) literature with recent insights on industry formation dynamics from innovation studies. It understands early path creation as conditioned by four systemic resource formation processes—knowledge creation, investment mobilization, market formation, and technology legitimation—that can be mobilized both from inside or anchored from outside the region. The use and value of the analytical framework is illustrated by a case study on on-site water recycling technology (OST), based on interviews with 40 experts in three Chinese city regions. The findings suggest that, despite possessing the least favorable initial conditions, a sizable OST industry developed only in Beijing. This is explained based on the specific anchoring process of the four key resources in the early development stage of the industry. Our results imply that EEG would profit from incorporating a broader set of variables than knowledge-based relatedness in explanations of regional industrial path creation.
Binz, C.; Truffer, B.; Coenen, L. (2016) Path creation as a process of resource alignment and anchoring: industry formation for on-site water recycling in Beijing, Economic Geography, 92(2), 172-200, doi:10.1080/00130095.2015.1103177, Institutional Repository

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      What do sustainable neighborhood planning, a urine fertilizer and a traditional Swiss Apéro have in common? The answer can be found in our new short film "Verhebets? A Resource-Oriented Apéro" about the potentials of a resource-oriented urban water management. The Global Science Film Festival has also now nominated the short film in the category "Best Short Film 2023".

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