BENGALURU: A visible light that is more cost- and energy-efficient than UV light can be used to disinfect water on a large scale, according to the new research conducted by Indian Institute of Science. Currently a lab-experiment, the team plans to scale it up for field-level work.
Professor Giridhar Madras and his student Rimzhim Gupta from the chemical engineering department of IISc, have discovered that a visible-light (a form of electromagnetic radiation that are visible to human eyes) photocatalyst can kill the common water-borne bacteria, E.coli. Photocatalysis is when light turns a substance into a catalyst that speeds up a chemical reaction.
It is advantageous to use visible light to purify the water because it is abundant in Nature and a large fraction of the solar spectra is visible light.
Professor Jayant Modak, deputy director of IISc and his team created a new kind of photocatalyst (the substance on which light acts) that works with visible light.
Where can it be implemented?
Krishna Rao Eswar, a student who is a part of this discovery, says that this photocatalytic disinfection can be a possible solution to fight different kinds of water pollution. “Photocatalytic treatment that is being carried out in the lab scale can be scaled up to clean lakes and river pollution by having several treatment facilities,” he says. “It can also be implemented for household water-treatments.” Photocatalysis can also breakdown organic content in the water.
Still in store for the future
A survey conducted by IISc on Bengaluru lakes at the beginning of this year showed that more than 90 per cent of the city’s lakes are polluted or encroached. IISc confirmed that this new technique can be used to revive lakes but lake experts are cautious, and will believe it once the “on-field” experiment is conducted.
“It is wonderful that such ideas come about but it is hard to say if it can be implemented,” said a geologist who does not want to be named. “Our first target should be conservation of natural resources followed by the treatment.”
However, IISc has no plans of taking this to the field as of now, because it will be a bit challenging to deal with water that has large and a variety of microbial population.