Rainwater treatment

In urban developments, rainwater becomes contaminated, and the contaminants are channelled into the receiving water system or the groundwater.

Contamination from surface areas comes from washing roads, pavements and car parks, etc., from car pollution and from human and animal waste.

Read more about this and find datasheets in Danish about the various treatment methods on the Danish Technological Institute website: http://www.teknologisk.dk/28273

Oil/water separators for car park run-off
In 2010, Lynettefællesskabet, a treatment plant, set up a working group to investigate surface run-off from car parks, one aim being to clarify the need for oil/water separators. In 2011 a report on the survey findings was prepared. Following on from this report, Herlev local authority drafted guidelines for handling cases involving surface run-off from local car parks. The guidelines, in Danish, can be seen here: Guidelines for var part run-off

Rainwater treatment in Aarhus
The City of Aarhus is focusing on a solution based on diverting rainwater via separate rain outlets after attenuation and treatment in large (45 mm) retention basins with a permanent water table. The authority aims to introduce such systems in areas where local rainwater infiltration (WSUD) is compatible with groundwater protection.

Read more about rainwater discharge and WSUD in Aarhus local authority here (in Danish).