REFERENCES

FOR THE PROTECTION OF OUR WATERS

REFERENCE HYDROSYSTEM SCHLESWIG

Treatment of rainwater runoff from a lead roof

The Haithabu Viking Museum in Schleswig is covered with lead for architectural reasons. As the building is located outside the town, the rainwater has to seep away or be discharged into a branch of the Schlei that requires protection. The removal of lead from the roof surfaces and facades amounts to around 6 kilograms per year for the entire building.

This means that there is an acute risk to the soil or water if the water seeps away without being cleaned or is discharged into the Schlei. As the chemical bonding forms of the lead in the rainwater runoff were not known, extensive preliminary tests were carried out. For this purpose, 1000 liters of rainwater runoff were collected and taken to the laboratory. Here, column tests were carried out in order to provide an optimally matched filter material.

Rainwater treatment
The rainwater runoff from the roof and façades is now treated using 3 Hydrosystem 1,000 metal filters and then infiltrated into the groundwater in three underground trenches next to the building. The filter systems were installed in concrete shafts. Due to the partly clayey subsoil conditions, there is a throttled outlet from the infiltration trenches into the Schlei. Water samples can be taken via a control shaft at the outlet and analyzed for lead concentrations. The aim is to reduce the average concentration of lead from around 6 mg/l in the roof runoff to below 0.025 mg/l in order to protect the soil and groundwater in the long term.

During the first year, monthly water samples were taken and the lead concentrations were reported to the lower water authority in Schleswig. This ensured that the cleaning effect was sufficient.

Year of construction: 2007
Type of connected surfaces: Lead roofs and facades
Area size: approx. 1,500 m2
Filter system: 3 hydro systems DN 1,000 metal

Daniel Betschner,
Master Professional of
Technical Management (CCI)
Project Engineer

Tel +49 (0) 7334 92460-32
Mail betschner@3ptechnik.de