Recycled tyres: now they’re also useful to purify water

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The Finnish company Apila Group takes advantage of the bacteria present on rubber surfaces to capture impurities and separate nutrients.

The is an appealing idea: using what is traditionally recognised as being dirty to clean what, on the other hand, is the maximum expression of purity: water. The latest innovation in the field of circular economy comes from Finland, where the Apila Group is developing a new method to reuse end-of-life tyres (ELTs) for the process of water purification. The technique is being tested in Kitee, in the east of the country.

The company, which deals with environmental consultancy, is working with the Finnish Tyre Recycling Company. “From pounded rubber it is possible to obtain a surface called biofilm – explains Sanni Pisto, engaged in the project with Apila Group – nitrogen, phosphorus and other nutrients in the water are bonded to this film. This is of fundamental importance for the purification process because the substances that researchers are trying to separate from water to purify it are eaten by microbes that proliferate on the tyre’s surface.”

This innovative solution adds to the multiple uses of ELTs. Indeed, vehicle tyres are recovered and transformed into powder for ecological flooring for sporting activities, soundproofing for buildings and to produce new energy and concrete.

The powder is also used as an additive in road paving. Many studies, supported by laboratory and paving tests, show that bitumen mixtures enriched with tyre dust improve drainability, adherence and sound absorption and minimize energy consumption in its realization and paving phases. What’s more, the final product is very long-lasting.