In many places in Belgrade there are now water containers filled with algae that can bind CO2. With the so-called "liquid trees", the LIQUID 3 pilot project wants to counteract the heavy air pollution and compensate for the lack of green space. Will this innovation also have a future in other cities? (Picture: LIQUID 3)
Stricter emission standards, driving bans, environmental zones and car-free Sundays - These are just some of the measures that cities and countries are taking to reduce harmful emissions from road traffic. At the same time, researchers from all over the world are still trying to find a solution for another side of the coin: What happens to the emissions that are released after all? Is there an efficient way to capture the pollutants now in the air? Researchers at the University of Belgrade answer with a yes. Because their innovation could significantly improve the air quality in the Serbian capital.
In several places in Belgrade, so-called "liquid trees" have recently been installed, namely urban photobioreactors, which were developed by scientists of the local university within the framework of a pilot project. These are not real plants, but glass boxes filled with water to which microalgae are added. It is precisely these microphytes that are believed to play an important role in combating pollution. With the help of solar energy, a pump transports the dirty city air into the container. There, the algae use photosynthesis to turn the captured CO2 into oxygen.
In other words, the way it works is similar to that of natural trees - with the added advantage that the microalgae can actually bind even more carbon dioxide than a tree. They are 10 to 50 times more efficient. However, the scientists at the University of Belgrade do not want to replace trees for this, but rather support them in their task of purifying the air. Especially where there is not enough space in the urban fabric for new trees and plants or where they suffer so much from air pollution that it is difficult for them to bind large amounts of CO2.
An interesting solution that could actually be of use in many cities and bring them one step closer to a cleaner future. It is true that the top goal of many governments remains the reduction of emissions and pollutants. However, this does not mean that environmentally protective measures should not be taken to possibly improve air quality and thus avoid late effects on citizens' health as well. The bottom line is that the air in big cities - despite successful green transport measures - is still heavily polluted by the many exhaust gases. In many places, there is a lack of green space to make the pollutant-rich air more bearable.
If successful, the pilot project from Belgrade therefore has the potential to contribute positively to air quality. But LIQUID 3 could make an even bigger difference if the "liquid trees" are also able to bind other pollutants besides CO2 - such as fine dust and nitrogen oxides. Their use would then significantly prevent pollution and thus complement other measures such as environmental zones - or even replace them over time. Will LIQUID 3 be able to filter more than carbon dioxide in the future? And will other cities invest in liquid trees as well?