Berlin – Audi Environmental Foundation and Technical University of Berlin have developed filters for urban runoff to prevent tire wear particles and other environmentally harmful substances from being washed into sewers.
The system “traps” dirt particles as close as possible to the location where they are generated – before rainwater can rinse them into the sewers, Audi explained in a 22 March release.
The project was launched in September 2020 and initial field and lab tests have now demonstrated the efficiency of the system, the statement added.
The Urbanfilter, said Audi, was deployed over a month ago on a busy road in Berlin and “mastered” its first stress test during a series of storms in mid-February.
According to the company, an estimated 110,000 tonnes of tire particles are produced in Germany per year, due to everyday car use.
From there, the particles are blown into the environment by the wind or washed by the rain as urban runoff through the sewers into the soil and rivers.
“Our goal is to take preventative actions wherever possible so that less microplastics get into the environment,” said Ruediger Recknagel, director of the Audi Environmental Foundation.
The filtering out of “ultra-fine particles”, however, is still presenting the team of researchers with challenges.
“The system has already passed tests with ground tire rubber between 20 to 1,000 micrometres (µm) in size in conditions of light to medium rainfall,” said Daniel Venghaus, research associate in the department of Urban Water Management at TU Berlin.
Now the team is working on improving the filter performance when there is strong rainfall.
The filter currently deployed in Berlin will remain in place for a year for further field studies and the investigation of the behaviour of genuine tire wear particles.