In urban areas, rainwater run-off can be contaminated by trace organic compounds such as biocides, plasticizers and flame retardents. During rain events, these substances are washed off from building surfaces such as façades and roofs as well as from traffic areas. Depending on weather conditions and urban structure, these pollutants are often discharged directly into surface waters via the rainwater drainage system without prior treatment.

On the basis of findings from other projects of the KWB and UMTEC (Institute for Environmental and Process Engineering; Ostschweizer Fachhochschule, Switzerland), the SpuR project aims to demonstrate strategies and specific technical measures with which such emissions can be reduced.

• Application of new façade coatings to reduce pollution “at the source”:
  A new paint product from a well-known paint manufacturer involved in the project is applied to the facade of a building in parallel to a conventional product. This coating does not contain the slowly degradable algicides used in conventional film protection (half-life 50 – 100 days). Instead, rapidly degradable active substances are used, which nevertheless ensure the long-term protection of the façade through a special encapsulation. A monitoring programme investigates the reduction of the environmental impact of this new façade coating in comparison to the conventional product.

• Use of new filter materials for rainwater treatment as “end-of-pipe technology”
  A new adsorber technology was developed by the company Funke (project partner) which is capable to retain dissolved organic trace compounds in addition to solids and heavy metals. The technology will be applied under real conditions in a decentralised rainwater treatment unit installed in an urban environment. The retention of relevant pollutants will be quantified.

Furthermore, the project will develop a planning framework for urban rainwater management which is to be kept as general as possible. Components include profiles of relevant measures as well as an easily applicable load model for pollution assessment of an urban catchment area to be performed with and without the planned actions. The entire procedure will be summarized in a guideline. The profiles of measures contain data on the load reduction potential at catchment level, feasibility and costs. The guideline is supposed to facilitate the selection of suitable measures (combinations) to cope with specific target substances or load situations, taking into account ecology and economic efficiency. The guideline will be used as an example in a specific surface water catchment in Berlin.

The SpuR project is being funded by the German Federal Environmental Foundation (DBU) for two years under the headline “Development of a façade protection system featuring minimised biocide content and a rainwater treatment unit with adsorber mixture to reduce the entry of trace organic compounds from urban areas into surface water“.

© Header Photo : Andreas FranzXaver Süß