Comparative multi-criteria performance assessment of alternative water infrastructure systems

This paper presents a new multi-criteria assessment tool enabling the comparison of conventional and innovative infrastructures and its application to a specific case in a mid-size German city, Lünen. The assessed infrastructure alternatives are a conventional system with centralised supply of drinking water, wastewater collection in a combined sewer system and central tertiary treatment in one case. In the other, more innovative system, one part of the wastewater is used decentrally to extract the contained heat, substitute one part of the drinking water and, after being passed into a park-like constructed wetland, improve the microclimate and biodiversity. The assessment method employed is utility analysis using a set of 21 criteria and 33 indicators. The comparative assessment of both infrastructure alternatives shows the superiority of the innovative system for most criteria.