German cities Cologne and Paderborn plan for source-separation with ANCHOR

In Cologne, the implementation of a source-separation system is currently being discussed for the development of the 87th city district, Köln-Kreuzfeld. The district covers an area of 80 hectares. At least 3,500 housing units are planned to be built, and new workplaces will be established. The concept, ‘The Woodhood - Garden City 2.0,’ comprises five so-called ‘hoods.’ These are small settlements in the immediate neighbourhood with an urban core. However, they will provide residents with a village-specific community life in the outer city, particularly to the west towards the edge of the landscape. Currently, an integrated rainwater management system is being developed, and round-table discussions with potential residents and interested citizens have been conducted. Regarding the source-separation aspect, the reuse of greywater is the first topic they are looking into. In this context, the reuse of greywater as service water and heat recovery are highlighted topics. As preparation, these potential use cases are being discussed for decentralised solution in a company building used by the maintenance and operation teams of the public wastewater company (StEB Köln).

In Paderborn, a new district, the Zukunftsquartier Paderborn, is planned to be developed over the next few decades. The district is a former military district covering a total area of 54 hectares. Currently, the first development, ‘Driburger Quartier,’ has started. The aim is the preservation of 12 (non-listed) existing buildings with partial conversion by the municipal housing association. The district is intended to be a low-runoff neighbourhood with a water management system as close to natural as possible. Thus, multi-coded areas will be designated, and a system of above-ground and underground retention areas implemented. The rainwater will be utilized for irrigation. Moreover, the implementation of semi-centralized innovative drainage systems, such as a source-separation of black and grey water, is being considered. The greywater could be used as service water at the building/block level to reduce drinking water usage, for example, for toilet flushing. The remaining heat in the greywater should be recovered and used locally. The next steps are the conversion of the updated master plan into a development plan as the basis for further planning steps and the development of an energy concept starting with a feasibility study.

Until the next physical meeting in Paderborn, Germany Community of Practice will gather guidelines for integrated rainwater management in our cities, as we have noticed that this topic is handled differently in each city. Furthermore, we will dive deeper into the discussion on decentralized and semi-centralized solutions for greywater treatment and will collect arguments for and against the two approaches.

For any questions about this article you can reach out to the author, Gregor Rudolp-Schöpping (Hamburg Wasser, DE).