In an interdisciplinary collaboration, EnviDan and landscape architect Schønherr have created a green development, a breeding ground for increased biodiversity and innovative wastewater treatment solutions for KLAR Forsyning, north of Køge.

Køge Municipality has designated an area of approximately 130 hectares in the northern part of the municipality as a new and sustainable development area for housing and business. The vision is that Køge North will be greater Copenhagen's new sustainable district, where blue and green areas and corridors will act as a "green development", which, in addition to creating urban nature, will also give the future building plots added value.

KLAR Forsyning thus works to establish multifunctional, recreational rainwater solutions with a high degree of treatment to contribute to fulfilling Køge Municipality's vision and to comply with environmental requirements, where there has been particular focus on limiting phosphorus emissions to the two watercourses, Skensved river and Snogebæk brook, due to a downstream Natura2000 site.

EnviDan has acted as the lead consultant, together with Schønherr, and designed, planned and supervised the construction of all rainwater and wastewater systems in close collaboration with KLAR Forsyning and the contractor, Tscherning.

A multi-stage construction process

Three phases of 6-8 sub-areas are planned, 4 of which have been built, including the area north of the new station. Here, rainwater is collected for treatment after a new treatment solution in The Green Belt (Det Grønne Strøg), which creates a total volume of about 3,000 m3 in a tight space among high square-metre prices. The plant consists of 5 interconnected basins which, through a combination of Sedipipes and planted sand filters, provide the necessary effective retardation and treatment, aimed in particular at phosphorus removal. These plants were delivered in September 2020.

At the other end of the project area (industrial area), a dry green basin, a transport corridor and two major constructed wetlands are planned and designed to receive road and site water from the future transport and data centre area. The basins have a total holding volume of 23,000 m3. Wetlands and a dyke were delivered in summer 2020 and summer 2021, respectively. Rainwater and wastewater drainage works have also been designed and executed throughout the project area.

Finally, in the central residential area, planning, hydraulic analysis and design work is ongoing in order to coordinate with other construction work in the best possible way. In the residential area, 2 treatment basins are currently being constructed using the same solution as The Green Belt, as well as 10 dry, local retardation basins with recreational elements, which are planned together with Køge Municipality's new road through the residential area. All necessary rainwater and wastewater pipelines are expected to be completed during 2021 and 2022.

Flexibility and continuous dialogue ensure a good process

EnviDan has carried out lead consultancy in collaboration with the developer KLAR Forsyning, landscape architect, Schønherr and contractor, Tscherning. Throughout the project, several planning and execution stages have been worked on simultaneously in different sub-areas of the project area in order to stay on schedule and utilise synergies. The project requires continuous dialogue with the developers and Køge Municipality, so flexibility and overview are keywords for the planning, design and execution.

Image: Schønherr

Christian  Bjoljahn


Christian Bjoljahn

+45 29 91 29 25