Drinking-water – too valuable for flushing

Beet auf dem Regenwasserspeicher

Each year, the ufaFabrik requires about 3000 cubic meters of water for flushing the toilets and watering the green roofs and façades. Before the rainwater was recycled for these purposes, the water that was used was valuable drinking-water, which was costly cleaned by water purification plants. Since the early nineties, the rainwater flows from the ca. 8000 square meters of roofs, asphalted roads and squares through the sewerage into the water storage facility, the former water works of the UFA film production company. The water works were removed and the walls were sealed to prevent evaporation and leakages. In the winter of 1997/1998, a new ceiling was installed inside the water storage facility.

At an assumed average rainfall of around 500 mm per year on the 8000 square meters of the ufaFabrik premises, 4000 cubic meters of rainwater could be collected per year – enough to cover the ufaFabrik’s required amount. In a sedimentation basin, stones, sand and mud sink to the bottom of the tank and floating items, like leaves, paper and wood are filtered when the water floods through gravel on a dividing screen into the second basin.

The roughly cleaned water is pumped into the constructed wetland and filtered again. The expanded shale in the substrate filters any remaining particles from the water. Soil organisms from the roots of reeds, rushes and waterlilies transform further pollutions into minerals, which are absorbed and used as fertilizer by the plants. This process cleans the water almost to the quality of drinking-water. The water is collected and stored in a cistern beneath the wetland and distributed among the buildings by a pressure boosting system.

In collaboration with the Technische Universität Berlin, there are several [research projects] running at this time, regarding the positive effects of constructed wetlands.