Effluents continue to flow into Hussainsagar

HYDERABAD: Effluents discharged by industries continue to flow into the Hussainsagar in spite of pipelines being laid to divert them to the Amberpet sewage and waste water treatment plant.
Tests of water samples collected from the lake in June this year from 12 different points have shown that the levels of chemical oxygen demand (COD) and the biological oxygen demand (BOD) indicate that there is no let up in flow of industrial effluents into the Hussainsagar.
These 12 water samples have been collected and tested by scientists at the National Geophysical Research Institute as a part of a Centre for Science and Industrial Research networked project titled Development of Techniques and Methodologies for Exploration, Assessment and Management of Groundwater in Hardrock Areas. NGRI director V P Dimri is chairman of the project.
For instance, a sample tested has shown that, while the COD is 58 milligrammes per litre (mg/l) the BOD is 10 mg/l. Tests on another sample has revealed that the COD is 80 mg/l, where as the BOD is 15 mg/l. The ideal COD for a water body is 25 mg/l and BOD is 10mg/l.
According to NGRI’s Groundwater Exploration and Management Group deputy director V V S Gurunadha Rao, a COD: BOD ratio of 4:1 indicates the presence of domestic sewerage, where as any ratio higher than this indicates the presence of industrial effluents.
The level of nitrates and phosphates in the water samples have also been found to be above permissible limits indicating inflow of domestic detergent wastes, Gurunadha Rao said. Higher than permissible levels of nitrates and phosphates lead to eutrophication - a slow death of water body and all life forms within due to lack of oxygen. Preliminary results of tested water samples also indicate presence of heavy metals in the lake.
As a part of the five-year study that is aimed at finding a solution towards improving the quality of water in the lake, the NGRI has established 120 observation wells to collect samples along the Jeedimetal, Kukatpally, Yusufguda and Jubilee Hills nalas.