Hussain Sagar cleanup mooted the organic way

Hyderabad: According to the latest data of Telangana State Pollution Control Board (TSPCB), the Dissolved Oxygen (DO) levels have hit an all-time low at the Hussain Sagar Lake. The immersion of 15,500 Ganesh idols was all that it took to bring the lake to its brink. Environmental scientists are now batting for an organic way of cleaning the lake.

Madhulika Choudhary, who heads the non-governmental organisation Dhruvansh and a strong advocate of Floating Treatment Wetland (FTW), says, “We have submitted a proposal to HMDA to replicate the Neknampur Lake model at Hussain Sagar.” She adds, “We have been able to prove that the model works. The Periodic Biochemical Oxygen (BOD) reading which was 27 mg/1 when we started the remedial programme is now between 3 to 10 which is acceptable.” Dr B V Subba Rao, a retired scientist and environmental specialist, has been advocating the treatment of polluted water using natural methods. He said, “Crores have been spent on Hussain Sagar but it has only got worse. There are natural methods to clean the lake.”

How does FTW work?
A variety of plants are introduced on the surface of the water. These plants grow on an island made up of thermacol and plastic bottles. Soil is added to enable the plants to grow. The plants absorb high content of phosphorous and nitrogen found in sewage water.

The FTW, based on the soil-less hydroponics technique, comprises four layers. Floatable bamboo forms its base over which styrofoam cubicles are placed. The third layer is composed of gunnybags. Gravel forms the final layer. Madhulika says, “vetivers, canna, cattalis, bulrush, citronella, hibiscus, fountain grass, flowering herbs, tulsi and ashvagandha are a few plants that we grow.” These root systems filter out sediments and pollutants.