This summer, algae, dressed in the Morris Column costume, settled in the heart of Paris to purify the air. Place Victor-et-Hélène-Basch, also known as Place d'Alésia, in the 14th arrondissement of Paris, more than 72,000 vehicles travel through the city every day, making it one of the most polluted places in the capital. That is why the Suez Group, in partnership with the French startup Fermentalg, has chosen to set up a new project there: tackling air pollution with the help of microalgae. When the legendary street furniture is converted to the latest principles of biotechnology ...
L’Suez, a French company specialising in water and waste management, in partnership with the French startup Fermentalg, which specialises in the cultivation of microalgae and innovative algal technologies, came up with the idea of installing high glass columns containing a large quantity of water in the manner of an aquarium on polluted sites (industrial zones, urban areas, busy roads, etc.). Inside, microalgae grow and multiply very quickly. Like all plant matter, these algae contain chloroplasts, which enable them to capture light and use it as a source of energy to transform the surrounding carbon dioxide into oxygen through a well-known biochemical reaction: photosynthesis.
In the case of the prototype developed by Suez and Fermentalg, the light source consists of an array of low-energy light-emitting diodes, whose light spectrum is optimised to allow optimal algae growth.
The microalgae, elaborated by Fermentalg, a company from Libourne (Gironde), are inserted in a tank of one cubic meter of water. The company selects strains of French algae. Since 2014, Philippe Lavielle's team has been thinking about "the creation of a kind of gas pump where carbon is fixed in the form of an organic mass". Fermentalg, contacted by the Suez group, is now collaborating in the manufacture of an "air purification system".
The carbon sink produces "green" energy that can be re-injected into the gas network according to the principle of the circular economy.
"A carbon sink of 1m3 of water can fix a quantity of CO2 equivalent to that of 100 trees." say the designers of this device. And the startup Fermentalg that developed the microorganisms also claims that they are "capable of capturing nitrogen dioxide (NO2)" from car exhausts. At Alesia, the level of NO2 exceeds the regulatory 40 µg/m3, according to Airparif data.
By sucking up carbon dioxide, these living organisms will grow and multiply. When they are too numerous, the system plans to evacuate the formed biomass to the nearest treatment plant, via the sewerage network. "With the growth of the algae, the biomass will be discharged into the sewage system and this creates a significant amount of energy, comments the director of Suez France. Once treated, the microalgae will be transformed into biogas and then into biomethane (natural gas network) to heat cities.
These Morris Columns are real reservoirs, 4 m high and 2.5 m in diameter. They were designed by Stories Agency When innovation meets design, the result is a clean, innovative and well-thought-out Morris column that combines sustainable development and everyday appeal, while respecting the urban landscape. »
For Suez, the trial was initially launched for six months: "This experiment will make it possible to determine the capacity of the process to capture the main atmospheric pollutants, such as microparticles.
Of course, nothing beats the oceans, forests or peat bogs, which absorb half of the world's anthropogenic emissions. But when we know that 50 to 70 % of the earth's oxygen mass is produced by algae and microalgae, which have a development potential ten to thirty times greater than terrestrial plants. ... Their cultivation is in full development; so why not integrate them into our cities?
Also read in UP': The living, big winner of the Reinventing Paris project
