Air Pollution kills three times as many people a year as HIV/AIDS, tuberculosis, and malaria combined. Air pollution is a menace that deteriorates the quality of human life. Deforestation due to urbanization, burning of fossil fuels, vehicular emissions are the prime cause of air pollution in urban areas. Trees are very useful for mitigating air pollution however in urban areas due to scarcity of space, nutrient rich soil, and pollution it is difficult to grow trees there. However to combat these challenges there is an innovative idea called “Liquid Tree” or “LIQUID 3” for short.
Liquid 3 is a clean energy photo-bioreactor which is designed for carbon capture. Photobioreactors are closed fermentation tanks containing numerous small photoautotrophic organisms (like microalgae, diatoms cyanobacteria etc) collected within a carefully controlled system that enables precise management of their growth. These photoautotrophic organisms in the photobioreactor absorb CO2 from the environment, carry out photosynthesis, and release oxygen, offering an effective solution to air quality concerns.
The LIQUID 3 photobioreactor wall has been made using microscopic fibers in plant cell walls called cellulose nanofibers and is equipped with a 600-liter water chamber housing a multitude of single-celled freshwater algae (microalgae) . These algae are resilient to both high and low-temperature stress, allowing them to thrive even during the winter season. Their primary function is the absorption of CO2 from the atmosphere, conducting photosynthesis, and subsequently producing pure oxygen. These algae also show luxurious growth even in the polluted environment without any constraints and are cost friendly and easily accessible, making this technology an better alternative for biological/ecological tool for air pollution mitigation in urban areas. After a month biomass of the algae is harvested, and the water is replenished with added minerals in the tank. The harvested biomass can also be employed as a fertilizer for crops and plants.
Furthermore, the “Liquid 3” has a solar panel on the top that captures solar energy, converting it into electricity, which is then used to power a pump responsible for introducing air into the tank through small perforations . The dead biomass of the algae is utilized by integrating it into Bio Photovoltaic Cell (BPV) . These cells use the photosynthetic properties of algae and convert it into electrical energy. During photosynthesis, electrons are generated. In BPV cells, these electrons are transferred to an anode, creating an electric current . As the nanofibers used to create liquid trees are highly conductive and this electrical supply also enables the tank to emit light providing light during the night acting as street lamps for urban areas.
The microalgae within the bioreactor possess the ability to replicate and replace the CO2 absorption equivalent to that of two ten-year-old trees or a lawn of area 200m. Furthermore algae act as an sanctifier and remove other pollutant such as nitrogen, phosphorus and heavy metal ion.Hence the Liquid 3 with the potential to sequester CO2 , release pure oxygen, and purify the atmosphere represents a promising solution to mitigate air pollution. Hence the Liquid 3 with the potential to sequester CO2 , release pure oxygen, and purify the atmosphere represents a promising solution to mitigate air pollution.

Chandan Kumar Rout

University/College name : Trident academy of Creative technology