HYDERABAD: Coming to the rescue of a polluted Neknampur lake, residents of Manikonda have turned to phytoremediation - using plants to contain pollution- in a first-of-its- kind initiative by citizens in and around Hyderabad to clean a polluted lake.
For the purpose, small artificial ‘floating islands’ will be created. These islands will have thermocol on four sides with plastic bottles attached to them to ensure flotation. At the centre a plastic mesh will be attached to it, on top of which a gunny bag will be placed followed by a layer of soil in which aquatic plants known to absorb pollutants like Indian water lily will be planted.
Once these islands are allowed to float in the lake, the plants will grow and their roots will reach into lake water, absorbing pollutants like phosphates and nitrates which get into lake due to illegal dumping of sewage.
An increase in phosphates and nitrates results in a corresponding increase in algal and microbial growth in the lake which consume lot of dissolved oxygen eventually leaving the lake devoid of enough oxygen for aquatic plants and animals to survive. Not surprisingly, the dissolved oxygen concentration in the Neknampur lake is 2 mg per litre (mg/L) whereas for propagation of aquatic life it should be at least 3 to 4 mg/L.
Madhulika Choudhary, a resident of Manikonda and head of an environmental NGO Dhruvansh, says, “Neknampur lake is dying a slow death due to the flow of sewage into it. Instead of waiting endlessly for the government to build sewage treatment plants and divert sewage from the lake, we will take an initiative that is effective, inexpensive and does not involve use of chemicals. I got the idea of floating islands from the Internet and, with help from HMDA, we are now building them.”
While small islands will be built and floated, there is a plan to build one as big as ten feet in length as well. These islands, Madhulika says, will prove helpful for more than just cleaning the lake.
She says, “The islands will also provide spaces for aquatic birds and turtles in the lake to nest or just rest safely. They will also add greatly to the visual appeal of the lake.”