Department Environmental Social Sciences

Decision-making for the transition from central to novel wastewater infrastructure systems

Ansicht Englisberg und Zimmerwald mit Blickrichtung auf den Gantrisch

Network infrastructure systems in urban water management deteriorate and will reach their end of life within the next decades. At this point we need to ask: How do we proceed? Do we rehabilitate or replace current network systems with the help of alternative systems? Disadvantages of centralized infrastructures such as low flexibility due to long planning horizons as well as high (investment) costs have great impact particularly under dynamic conditions and in rural, sparsely populated areas. During the last years, novel, decentralized technologies have gained increased attention for instance because they promise higher flexibility.

In Switzerland and similar countries, centralized wastewater infrastructures are widely established. It remains to be clarified under which conditions decentralized systems are really advantageous. In case they are competitive it needs to be investigated who is going to make which decisions at which point of time to guarantee a successful transition from the current central system to a decentralized alternative. It remains unclear, how local and cantonal stakeholders can be involved effectively into the long-term decision process.

This project aims to identify alternative wastewater systems that require less network infrastructure. The advantages and disadvantages of alternative, innovative systems will be evaluated with respect to future uncertainties (e.g. climate change, population shrinkage/ growth, technology development) as well as with regard to the expectations of stakeholders. Within the project at least one rural community in the canton of Solothurn will be investigated as case study.

The project is a conjoint research activity of Eawag’s departments Environmental Social Sciences (ESS) and Urban Water Management (SWW). The research is conducted in intensive collaboration with the environmental agency of the canton of Solothurn (AfU SO). The project is embedded in the Wings („Water and sanitation innovations for non-grid solutions“) at Eawag.

Team

Philipp Beutler Project collaborator, Cluster: DA Tel. +41 58 765 5285 Send Mail
PD Dr. Judit Lienert Group Leader, Cluster: DA (Decision Analysis) Tel. +41 58 765 5574 Send Mail
Prof. Dr. Max Maurer Tel. +41 58 765 5386 Send Mail

Publications

Preference change in stakeholder group-decision processes in the public sector: extent, causes and implications

Public decisions are typically related to large investments leaving long legacies. We should therefore strive for wide societal agreement regarding such decisions, which meet the diversity of preferences between stakeholders and over time. But if, how and why do stakeholder preferences change over time? In decision analysis, these questions received little attention. We explored them using three real-world public decision processes, based on Multi-Criteria Decision Analysis (MCDA). We used repeatedly elicited ranking of objectives over time. These were obtained during three to five moderated workshops we organised several months apart (total N = 200 questionnaires, and 100 stakeholders). We analysed individual and aggregated (group) preferences, their changes and potential drivers including demographic and experience variables. We also analysed the effect of preference evolution on the performance of decision-alternatives with MCDA over time. We found that stakeholder preferences often changed over time, both on an individual and group level. These changes did not systematically diminish over time, but some convergence of preferences was observed for stakeholders who repeatedly participated in workshops. High-ranking objectives were relatively stable and similar between stakeholders. While preference changes could not be explained by demographics and personal experiences, repeated interaction with the decision problem might play a role. Neither the observed disagreement between stakeholders, nor the preference changes over time affected the best and worst performing alternatives in our decision problems. Thus, despite changing stakeholder preferences over time, public decision-makers can contrive robust solutions to complex public decision problems in the present.
Kuller, M.; Beutler, P.; Lienert, J. (2023) Preference change in stakeholder group-decision processes in the public sector: extent, causes and implications, European Journal of Operational Research, 308, 1268-1285, doi:10.1016/j.ejor.2022.12.001, Institutional Repository

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
Beutler, P.; Lienert, J. (2020) Zukünftige Abwasserentsorgung im ländlichen Raum - Synthese zur Entscheidungsunterstützung in den Fallstudien im Solothurner Jura. Abschlussbericht, 65 p, Institutional Repository

Zukünftige Abwasserentsorgung im ländlichen Raum - Fallstudie 2. Abschlussbericht für die Gemeinde

Wie kann die Abwasserentsorgung in einer ländlichen Gemeinde in der Schweiz in Zukunft gewährleistet werden? Welche Bedürfnisse der lokalen Nutzer/-innen muss ein modernes Abwassersystem erfüllen? Das Wasserforschungsinstitut Eawag und das Amt für Umwelt Solothurn (AfU) sind diesen Fragen gemeinsam nachgegangen und zeigen die Ergebnisse in der vorliegenden Studie auf.
In der Schweiz ist die überwiegende Mehrheit aller Einwohner/-innen an ein zentrales, netzgebundenes Abwassersystem angeschlossen. Auch im Kanton Solothurn besitzen alle ländlichen Gemeinden ein solches System aus Kanalisation und Abwasserreinigungsanlage (ARA). Diese Systeme wurden ursprünglich mit Subventionen vom Kanton und vom Bund realisiert. Langfristig müssen diese nach dem Verursacherprinzip durch Gebühren finanziert werden.

How to ensure future wastewater disposal in rural communities in Switzerland? What needs of local stakeholders should a modern wastewater system meet? Eawag, the Swiss Federal Institute of Aquatic Science and Technology, and the Office for the Environment Solothurn (AfU) have jointly investigated these questions and present the results in this study.
In Switzerland, the vast majority of inhabitants are connected to a centralized, grid-based sewer system. In the canton of Solothurn, all rural municipalities make use of such a system consisting of a sewer network and a wastewater treatment plant (WWTP). From the 1960s to the early 1990s, communities initially implemented these systems with subsidies from the cantonal and the federal government. To finance these systems in the long term, legal regulations prescribe fees to be charged according to the polluter-pays-principle.
Beutler, P.; Lienert, J. (2020) Zukünftige Abwasserentsorgung im ländlichen Raum - Fallstudie 2. Abschlussbericht für die Gemeinde, 145 p, 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
Beutler, P.; Lienert, J. (2020) Zukünftige Abwasserentsorgung im ländlichen Raum - Fallstudie 1. Abschlussbericht für die Gemeinde, 28 p, Institutional Repository

Posters

"Schwierige Entscheidungen im Milizsystem" (Poster Methode MCDA; Mai 2020) (only in German)

"Zukünftige Abwassersysteme im ländlichen Raum" (Poster Fallstudienergebnisse; Mai 2020) (only in German)

Webinar

"Potenziale dezentraler Abwassersysteme" (Webinar VSA, Vimeo, Youtube; Juni 2020) (only in German)

Contact

Philipp Beutler Project collaborator, Cluster: DA Tel. +41 58 765 5285 Send Mail

Project information

Duration: 05/2016 to 02/2020

Posters

Schwierige Entscheidungen im Milizsystem

Schwierige Entscheidungen im Milizsystem (only in German)

 

Zukünftige Abwassersysteme im ländlichen Raum

Zukünftige Abwassersysteme im ländlichen Raum (only in German)