Charting a Path for Innovative Toilet Technology Using Multicriteria Decision Analysis

Abstract

Practical and theoretically sound methods for analyzing innovative environmental technologies are needed to inform public and private decisions regarding research and development, risk management, and stakeholder communication. By integrating scientific assessments with a characterization of values, multicriteria decision analysis (MCDA) supports the ranking of alternative technology pathways on the basis of technical, financial, and social concerns. We applied MCDA to evaluate the use of NoMix urine separating toilets for managing environmental risk and postponing expensive upgrades to a large wastewater treatment plant near Zürich, Switzerland. Results indicate that, given current priorities, no single, fixed course of action (including the status quo) will be desirable to all stakeholders over the considered time horizon. However, a path forward is suggested that is not significantly disadvantageous to any stakeholder now and leaves open future options, allowing society to achieve overall greater benefits if priorities change, new environmental risks are revealed, or technology improves. While our analysis focuses on a particular catchment in Switzerland, many communities worldwide are faced with an aging and inefficient wastewater treatment infrastructure while also experiencing growth and development. Our framework can help these communities balance the conflicting objectives of diverse stakeholders and gain insight into the role that urine separation can play in transitioning to a more comprehensive and sustainable urban water management system.

Real-life efficiency of urine source separation

“…There are other (combinations of) transport possibilities, but the most difficult optimization of storage capacity follows from the transport in combined sewers. A stakeholder perspective on different urine storage and transport options is presented in Borsuk et al (2008). For 'wave transport', high safety levels would have to be set because overflows would be severe with concentrated urine in the sewer.…”

Application of a multi-criteria decision model to select of design choices for WWTPs

“…The Novedar_EDSS has been conceived as integrated software employing artificial intelligence techniques combined with different analytical tools: multi-criteria decision analysis (MCDA) methodologies (Flores-Alsina et al 2008;Borsuk et al 2008), life-cycle analysis (LCA) (Lundin et al 2000), cost-benefit analysis (CBA), and environmental-benefit analysis (EBA) (Molinos-Senante et al 2012). The EDSS core consists of two different knowledge bases: specifications (S-KB) and compatibility (C-KB), constructed using expert knowledge of WWTP technologies (gathered from Novedar Project partners, the scientific literature, project-related engineers and interviews with companies and wastewater treatment authorities).…”

A novel deliberative multicriteria evaluation approach to ecosystem service valuation

“…Another issue related to monetary valuation is the inability to capture characteristic ecosystem properties such as nonlinearity and irreversibility (Limburg et al 2002, Winkler 2006a (Belton and Stewart 2002). In MCDA, the multidimensionality of ecosystem services can be addressed in the valuation process, allowing for a representation of the trade-offs among them (Gregory et al 1993, Borsuk et al 2008, Chan et al 2012. The ability to quantify the provision of diverse ecosystem services under alternative scenarios has been considerably improved in recent years (Samal, Wollheim, Zuidema, et al, unpublished manuscript).…”