BENGALURU: The Indian Institute of Science (IISc) is commencing a research project on Monday that may help solve the mystery surrounding the repetitive fires at Bengaluru’s infamous Bellandur Lake.
While scientific experts have maintained that chemical pollutants in the water body have been causing the fire and smoke, others say it is man-made -- even by carelessly thrown lit cigarettes or beedis.
Now, scientists from the IISc and a team of researchers from the University of London are looking at developing optical fibre sensors that can detect a range of biological as well as chemical contaminants in water, which may help solve the persisting mystery of fires in Bellandur Lake. This will be the first device that can measure levels of both biological and chemical substances in water and will be achieved by combining two sensing platforms -- one using nanotechnology and another using optical fibre.
Prof S Asokan, Department of Instrumentation and Applied Physics, IISC, said the use of optical fibres for sensing is a fairly recent phenomenon, and the team from IISc has carried out a lot of work in this area.
An optical fibre typically consists of a clad with a width of 125 micron and a core width of 10 micron. “We etch out the clad partially or fully and coat it with materials such as carbon nanotubes and graphene oxides, and make it sensitive so that the pollutant molecules can bind on to the coating. The refractive index of the core is varied sinusoidally along its length, which causes light signals of specific wavelengths to reflect back instead of propagating further, and those wavelengths can be measured to gauge the presence of impurities present,” Prof Asokan explained.
The team from London complements the IISc team in several ways. It has gained expertise in coating sensitivity while the IISc team have excelled in the development of optical fibres.The main advantage of a device is ‘multiplexing’, that is, levels of multiple impurities can be measured with a single device. In addition, Asokan said, it does not need any power source and is chemically inert. “We are also working simultaneously to make it low cost and we want to involve the BWSSB too,” he said.
Despite fire breaking out several times on Bellandur Lake, neither experts nor the residents close by, have been able to pinpoint the precise reasons. The persisting mystery and the fact that the lake is immensely polluted and neglected, has gained the lake an infamous tag globally.However, the IISc’s new device that will be developed has raised hopes of finding an answer and fixing the problem of lake pollution in the city, besides ensuring good water quality in future.