BANGALORE: The 950-acre Bellandur Lake — the city's biggest and worst polluted water body — is getting a clean-up. But unlike Ulsoor Lake, rejuvenation does not involve the mess of desilting and draining the filth out. Nor the whopping cost. Simple bio-remedial techniques are slated to be used, and are billed to cost only Rs 5.5 crore. "This technique promises to ensure minimum disturbance to the existing ecology at Bellandur Lake," say officials. The Ministry of Environment and Forests has approved the state's proposal to restore the 200-year-old lake through microbiological agents.

"Microbiological agents, capable of breaking down organic and inorganic sediments will be introduced into the lake, followed by aeration and oxygenation processes by the use of compressors and diffusers," explained CEO of Lake Development Authority and chief conservator of forests A.K. Varma. "The method has been tried and tested on Powai lake in Maharashtra and is being experimented at Ooty as well. Draining and desilting the 4-metre silt is practically unthinkable and impossible for a massive lake like Bellandur," Latha Krishna Rao, secretary, Department of Environment and Forests, told The Times of India. The process does not make the water turbid. In fact, phenolic and oil compounds will be broken down in a manner that the silt itself gets cleaned up. Enzymes and microbiological agents will be released into the lake for the revival of life forms in the water body.

Under the Rs 46-crore National River Conservation Programme (NRCP), the Bangalore Environment Action Plan has asked the Bangalore Water Supply and Sewerage Board (BWSSB) to relay the diversion channels which enter the lake, said Rao. This apart, the BWSSB has been asked to upgrade the K.C. Valley catchment area, the biggest in the city. The Lake Development Authority is the coordinating agency to implement the one-year project, which is set to begin within six weeks. Once Bellandur Lake is cleaned up, restoration of connecting lakes such as Varthur will be taken up in a phased manner. Meanwhile, the upper portion of Bellandur such as Madiwala and Agaram in the Challaghatta Valley lake have been taken up, added Varma.