A `fresh' approach to three polluted lakes
By M.L. Melly Maitreyi
Source: The Hindu, Wednesday, Dec 04, 2002.
HYDERABAD Dec. 3. With remarkable metamorphosis and beautification of once highly polluted three major lakes at Safilguda, Saroornagar and Langer Houz, the stage is now set to make their sewerage treatment plants (STP) operational in the next 15 days.
It will then take the `Lake Conservation Programme', initiated by the Hyderabad Urban Development Authority (HUDA) with the assistance of Royal Netherlands Embassy (RNE), under the `Green Hyderabad Environment Programme' (GHEP) to its logical conclusion. That is the direct letting of sewage and sullage from the neighbourhood into the lakes will be stopped and with it the pollution of the lakes.
The three major lakes are among the 85 identified for the integrated lake treatment and conservation programme under the GHEP. The 85 lakes were grouped into Category-I or problematic lakes and Category-II or non-problematic lakes based on the level of pollution assessed by analysing their waters and sediments. The above three lakes are among the 18 problematic lakes taken up by the HUDA under the Inception Phase.
``The trial runs of the STPs constructed at a cost of Rs.8.72 crores adopting the state-of-art technology have commenced two days ago,'' the Executive Director of the Green Hyderabad Project, K. Bhoopal Reddy, told The Hindu . The trial runs were being supervised by the Bangalore- based consultant, Venkatraman. "The trial runs are to ensure no leakages and to take sufficient precautions before the STPs become operational.''
Once the STPs were commissioned at the three lakes, the direct letting of sewage into them would be stopped. A sewer networking in the neighbourhood was under progress and they would be connected to the STPs for treatment of sewage by extended aerated treatment system.
Mr. Reddy said the unique extended aeration system generates minimum quantity of gases and was highly suitable for densely populated areas because of eco-friendly technology. More water would be oxygenated and BOD removal efficiency would be very high, and generation of sludge would be minimum. After the sewage treatment, the residual nitrates and phosphates would be further reduced in the wetland where special aquatic weeds would consume the nitrates for their growth. The biological process in the wetland improves further the quality of water with the result that the treated water would get enhanced to potable level. Such quality of water released into the lake would recharge the underground water resources in the neighbourhood.
The Executive Director said, while the STPs at Safilguda and Langer Houz would almost meet the quantum of sewage generated in the surrounding residential areas, in the case of Saroornagar, the surplus sewage would be let into the River Musi through a trunk sewer line already laid by the HMWSSB. The purification of Musi waters would be taken up under the proposed massive National River Conservation Project.
He said they were coordinating with the respective municipalities in the case of Safilguda and Saroornagar lakes and the MCH in the case of Langer Houz for inter-connectivity of sewer lines with the respective STPs. "Majority of households have taken the sewerage connection and the rest would fall in line,'' he said.
The RNE team, which recently inspected the lake sites and observed the technology, had expressed its satisfaction and said the same technology could be extended to other lakes as well, Mr. Reddy disclosed.