Deccan Chronicle 18.11.2009

Old sewer lines to be replaced

Bengaluru, Nov. 17: In a bid to improve the city’s sewage system, the Bangalore Water Supply and Sewerage Board (BWSSB) has earmarked Rs 360 crore to replace a 109 km stretch of trunk sewer lines under Environment Action Plan C. The project, which will be taken up in 2010-11, is expected to be completed within 24 months after commencement of work, says BWSSB chairman P.B. Ramamurthy.

The project, which will link sewer lines to sewage treatment plants (STPs), will allow BWSSB to treat 90 per cent of the sewage water for non-drinking purposes, he adds.
Less than 50 per cent of the sewage generated in the city is available for treatment due to old and outdated sewage lines. Though BWSSB has 14 STPs capable of treating 718 million litres per day (mld), these plants get only 360 mld due to a leak in the sewage link.

“Trunk sewer lines with a diameter of more than 450 mm, which run up to 246 km in the city, are 25 to 30 years old. Hence, under Environment Action Plans A, B and C, they will be replaced and linked to STPs,” says chief engineer (waste water management) S.M. Basavaraju. Under Environmental Action Plan A, which was taken up in 2003 and is approaching completion, sewer lines measuring 33 km have been replaced at a cost of Rs 46.27 crore.

As part of Environment Action Plan B, which was launched in June this year, BWSSB has been replacing sewer lines stretching across 80 km at a cost of Rs 176 crore. This phase is expected to be completed by December 2010. Lateral sewer lines measuring below 450 mm in diameter run a length of 4,000 km in the city.

Since these pipes are old and worn out, most of them have been replaced under the annual maintenance project. BWSSB plans to spend Rs 800 crore to establish nine more STPs, which will have the capacity to treat 314 mld of sewage water. Around 80 per cent of the water supplied every day in the city is used for non-potable purposes and hence, turn up as sewage water.