Wastewater treatment facilities urgently needs energy sustainable technology and processes to tackle global water scarcity as well as to reduce energy insecurity. In this context, Nanobubbles have emerged as a potential solution to the problem and has drawn attention of many researches because of their potential applications.
Nanobubbles are nano-size bubbles with diameters below 200 nanometers that have unique physicochemical and mechanical properties that make them particularly useful for the water and wastewater treatment:
- Due to the very small size, they have an extremely high surface/volume ratio, what intensifies the oxygen transfer efficiency (OTE) due to the larger surface of contact between the gas and liquid phases. For example, the interchange surface of a volume of Nanoparticles of 100 nm is about two thousand times the surface of the same volume of micro bubbles, and tens of millions times compared with normal bubbles.
- They have smaller or virtual disappearance of buoyancy, this is, nanobubbles don´t rise through the water as other macro or micro bubbles, what enable them to have longer residence time in the water.
- Nanobubbles are very stable and can remain suspended in water for several days, even months, what means that the oxygen that you have injected is operating for long time, so the oxygen requirement decrease considerably.
- Increase water´s gas holding capacity by up to 20% compared with micro bubbles.
- Excellent mixing what allow the aeration of the entire water column.
- Finally, one of the most interesting property of the Nanobubbles is their ability to generate highly reactive free radicals and the enhancement of hydroxyl radicals formation, what give Nanobubbles the property of the iper-oxidation, what is an advanced oxidation process able to remove organic materials in a very rapid and efficient way.
