In the next six months, researchers at the Indian Institute of Technology-Bombay (IIT-B) are looking at treating water from Powai lake through their natural “constructed wetland” treatment system.
The constructed wetlands use the natural processes of exchange between the root, soil and surrounding microbes to treat organic and inorganic pollutants present in sewage, in a controlled environment.
Through this technology, Canna, a flowering plant sourced from a roadside marshy pool in Panvel, has been able to reduce the biological oxygen demand (BOD) from IIT-B’s raw sewage by up to 86 per cent since 2013, according to Shyam Asolekar , professor at the Centre for Environmental Science and Engineering (CESE), IIT-B.
The 13m x 3m x 0.6m pilot ‘constructed wetland’ abuts the lake near the sewage well of the campus. At the same spot, the researchers hope to create a wetland four times the size as a test plant to show the possibility of in situ treatment of water from Powai lake. The logic is simple, says Asolekar. “We know plants absorb water and use up the nutrients in it and in the case of waste water, the pollutants are nutrients for the plant. We settled for Canna as it removes maximum pollutants in the least amount of time. In waste water treatment, bringing water to the treatment plant is the most expensive part. In our case, the system uses natural plants, pumps operated using solar energy and requires minimal construction. The plant is situated right next to the lake and can be further used in nullahs, eliminating the need to carry water to the treatment plant,” he adds.
Last week, BMC engineers visited the campus and were keen on creating a constructed wetland near the main gate entrance to treat water from Powai village that flows through the IIT campus into the lake.
Further, the BMC has identified 12 locations along the lake’s periphery where untreated waste water through runoffs and pipeline pollutes the lake. In addition to this, the BMC is also in the final stages of awarding tenders for removing water hyacinth that has invaded large portions of the lake. This is part of the Rs 2.6-crore Powai Lake Rejuvenation project that the BMC has undertaken to clean the 2.1 sq km lake.