HYDERABAD: Revealing drastic decline in the quality of water in Hussainsagar, it was recently found that the dissolved oxygen (DO) in the water body is zero. As a result, there is hardly any aquatic life left in the lake, except catfish. Even migratory birds have given up their periodic visits to the lake. The decline in water quality can be attributed to continuous discharge of sewage into the lake from Balkapur and Banjara nalas.
HMDA officials said that on a daily basis, about 80-100 mld of untreated water is being discharged into the lake. Sewage from these nalas are being let into the lake as HMWS&SB has taken up repairs of main trunk sewer since October 2017 on NTR Marg with ‘Cured In Place Pipe’ (CIPP) structural lining.
A portion of the 1600/1800 dia sewerline, that runs from sewerage treatment plant at Necklace Road to GHMC’s head office, collapsed in front of NTR Gardens on September 24, 2016, resulting in closure of the road. The pipes were replaced temporarily by the Board. To solve the problem permanently, the Water Board studied various options and zeroed on CIPP.
Once the CIPP sewer is ready in a week or two, Banjara Nala and Balkapur nala sewage will be diverted through trunk sewers instead of being discharged directly into the lake. Hyderabad Metropolitan Development Authority (HMDA) has decided to take up interventions like microbial cultures/enzymes, increasing growth of aerobic bacteria or any other innovative technology to improve the quality of water in the lake and also reduce foul emissions.
The intervention should consists of designing and implementing systems that will prevent algal growth and enhance DO, in addition to improving water quality, sediment quality, reduce the concentration of the suspended matter (turbidity), increase transparency of water, reduce the presence of the pathogenic bacteria, etc. HMDA has taken up Hussainsagar Lake and Catchment Improvement Project (HCIP) with financial assistance of JICA to bring the lake to its original glory. As part of the project, HMDA completed works like diversion of sewage inflows, STPs to discharge high quality of treated effluent in the lake and nala improvements in the catchment.