BiotopeCity: Greywater Use – Potentials in and Around Buildings
In densely built cities, water is becoming an increasingly precious resource. At the same time, a large amount of so‑called greywater is produced there every day – that is, lightly polluted wastewater from showers, bathtubs, hand basins, or washing machines. After treatment, this water can be reused – for example, for watering green spaces, roof gardens, and greened façades.
The dense city as nature – greywater makes this possible!
In the lecture by Oliver Pongracz and Susanne Formanek, the innovative use of greywater will be demonstrated. This is not only about watering plants, but also about recovering heat – an essential contribution to the energy-efficient refurbishment of existing buildings. Using already implemented solutions, the speakers explain how urban density, ecological diversity, energy savings, refurbishment, and social quality can be combined.
Using the example of the conversion of Kauergasse 2 in Vienna, it is vividly demonstrated how greened façades, roofs, and courtyards create new habitats for plants and animals – even in densely built-up neighbourhoods – while noticeably improving the microclimate. The project stands as an example of a new urban building culture in which nature and the city are no longer opposites, but together form the basis for a resilient, liveable future.
In addition, Susanne Formanek is a resident of a flat in Kauergasse and reports on the daily use of greywater.
This lecture series is a cooperation between the Foundation Biotopes City, the Institute for Landscape Planning (ILAP) and the Institute of Engineering Biology and Landscaping (IBLB) of the BOKU University.
Zoom link:
https://bokuvienna.zoom.us/j/67848465261?pwd=RktrL2M5VzR0SDdaNmFTMlRjUGs3Zz09
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Please make a note in your agenda of the following lectures:
Tuesday, February 10, 2026, 17.00 hrs:
Experience with Green-Inclusive Building, Maike van Stiphout
This lecture will be held in English.