A `fresh' approach to three polluted lakes
By M.L. Melly Maitreyi
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.
`Harness Adyar river water'
By T. Ramakrishnan
CHENNAI DEC. 3. Even as the Chennai Metropolitan Development Authority is close to taking a decision on the appointment of a consultant for the Thiruneermalai multi-purpose reservoir scheme, a prominent city-based NGO has written to the Chief Minister, Jayalalithaa, to execute a project on harnessing Adyar river water.
(The Thiruneermalai project also envisages the use of Adyar river and provides for the construction of a reservoir across it.)
"If implemented, the scheme will cleanse the Adyar. No longer will the heavily-polluted river remain an eyesore to the city. The scheme will also take care of the drinking water supply requirements", M. B. Nirmal, founder, Exnora International, stated in his proposal.
The Exnora plan provides for constructing check dams in and around Anakaputhur and Nandambakkam, bringing a halt to cleaning of lorries in Ramavaram (which is located along the river) and doubling the capacity of sewage treatment plant in Nesapakkam.
Meanwhile, the CMDA is now scrutinising bids received for selecting the consultant for the Thiruneermalai project, which also envisages damming of the Adyar river. "We may complete the work in two weeks", an official says.
The successful bidder will suggest ways to execute the Thiruneermalai scheme on BOT (build, operate and transfer) mode and explore the possibilities of real estate development in areas surrounding the proposed reservoir.
This proposal is based on a report prepared by the Public Works Department, which examined the technical feasibility of the scheme. Since the early 1990s, P.V.Sahadevan, former PWD chief engineer, has been advocating the need for constructing a reservoir in Thiruneermalai. Four years ago, an exclusive survey and investigation team was set up and it went into the specifics of the scheme.
The location of Thiruneermalai holds significance because it is where the drainage courses of Guudvancheri, Padappai, Manimangalam and Somangalam join Adyar and it accounts for 80 per cent of the total catchment of 800 sq km. Besides, the surplus channel of Chembarampakkam tank joins the river.
The issue of entrusting the project on the BOT lines cropped up sometime back as the policy makers felt that the Government might not find adequate funds to finance it. On a conservative estimate, about 300 mcft (million cubic feet) of water can be stored there and the project cost is in the range of Rs. 200 to 300 crores. The earth, excavated for building the reservoir, can be used for land-filling and the areas, thus reclaimed, be developed for real estate. These areas can be in and around the reservoir.
As for increasing the capacity of the Nesapakkam plant, Chennai Metrowater planned to cover it as part of the ongoing Chennai City Rivers Conservation Project.
In his communication, Mr Nirmal stated that the Adyar river was being polluted by the outfall of sewage from panchayats and residential colonies situated along its course. A substantial section of washermen were using the polluted river water for cleaning clothes. "As this practice is not healthy for those entrusting their clothes to the washermen, a suitable alternative can be offered", he said.