Resource-optimized transformation of mixed
and separate sewer systems in existing districts

Cross-linking urban development and water management aspects for cities of the future

Increasing heavy rainfall events and the growth of urban districts constitute major challenges not only for urban drainage. Three neighborhoods in Braunschweig, Hannover and Hildesheim will serve as examples for district planning that combines urban quality issues and water management aspects in the long term.

Objectives and procedure
The objective of the project is on the one hand the development and testing of a flexible, multi-measure planning method to transform existing drainage systems. On the other hand, innovative solutions are being implemented in the three districts at different urban planning levels. In Hildesheim, for example, the aim is to increase the inflow capacity of the WWTP during heavy rainfall events and differentiate between possible discharge ways based on rainwater qualities. In Braunschweig, precipitation water from facades and roads will be investigated to determine the content of biocides and microplastics. In Hannover, operational aspects of blue-green infrastructure elements (green roof, moss facades, cisterns, ponds) will be evaluated under the aspect of how to implement multi-functional components into the planning routine of cities.

Expected results and transfer
The results will be published as methodological recommendation for strategic cross-divisional urban planning supplement by a web-based module catalogue.

Project title
TransMiT – Resource-optimized transformation of mixed and separate sewer systems in existing districts with a high settlement pressure

Project website


Funding code

2.361.460 €

Dr. Maike Beier
Leibniz Universität Hannover
0511 762-2898

Project partners
Technische Universität Carolo-Wilhelmina zu Braunschweig
Technische Universität Dortmund
Universität Leipzig
BPI Hannover – Verworn Beratende Ingenieure
Spar- und Bauverein eG
Wohnungsgenossenschaft Gartenheim eG
Stadtentwässerung Braunschweig GmbH
Stadtentwässerung Hildesheim Kommunale AöR

Version of
August 2020

Contributions at the kick-off event in June 2019