Residents around Bellandur lake are upset again as the frothing and stink in the water body has gone up by several notches in the last two weeks. This is being attributed to diversion of untreated sewage from two upstream lakes – Devarabeesanahalli and Iblur lakes where the Bruhat Bengaluru Mahanagara Palike (BBMP) has taken up rejuvenation projects without adequate Sewage Treatment Plant (STP) infrastructure.
Resident Welfare Associations (RWAs) in Bellandur are planning to organise a protest next week against the diversion turning Bellandur lake into a cesspool of sewage.
Seema Sharma, a resident, said that most people living around the lake are complaining of severe headaches after the stink from the lake being increasing. “The stink is the worst early in the morning. It started suddenly and on investigating the source, we realised sewage from many upstream lakes was being diverted into this lake,” she said.
Nagesh Aras, another resident, said that it is unacceptable to rejuvenate lakes by diverting sewage into other lakes. “The government seems to be in a hurry to show development of lakes. But rejuvenation of lakes without treating sewage and only bypassing it will prove lethal to both lakes – the rejuvenated lake will have no water and the lake to which sewage is diverted will turn into a cesspool,” he said.
Bellandur lake has 46 lakes upstream. If sewage from all these lakes are diverted to Bellandur, the lake will be reduced to a sewage pit for the city, he said.
BBMP has now taken up rejuvenation of Devarabeesanahalli lake (7 acres) and Iblur lake (12 acres) at a cost of ₹3 crore each.
Ideally, lake conservation experts said that BBMP must install STP infrastructure to treat the entire sewage let into the lake before rejuvenating it.
But the BBMP has no plans to put up adequate STP infrastructure at either of the lakes. Sewage inflow into Iblur lake is over 5 MLD and into Devarabeesanahalli lake is over 4 MLD. BBMP has called for a tender to put up an STP of 0.5 MLD at Iblur lake, but is looking for corporate sponsors to put up a 0.5 MLD STP at Devarabeesanahalli lake.
This essentially means that of the total of 9 MLD sewage from the two lakes, BBMP plans to treat only 1 MLD and let the rest into Bellandur lake.
‘BWSSB’s job’
T. Jagannath Rao, DCF, lakes, BBMP, who is spearheading the two projects, said the civic body does not have the funds to put up STPs to treat the entire sewage inflow into these lakes and is is essentially the job of the Bangalore Water Supply and Sewerage Board (BWSSB). “We are trying to install micro-STPs to treat enough water to fill the lakes once they are rejuvenated. We are diverting rest of the sewage to downstream lakes. This is not a new phenomenon,” he said.
For instance, Saul Kere, rejuvenated three years ago, has a sewage inlet of over 40 MLD. But BBMP has put up two micro STPs with a total capacity of 1 MLD while the rest is diverted into Bellandur lake. “If I want to treat all the sewage in Saul Kere, I need an investment of over ₹100 crore, which I don’t have,” he said.
Lake conservation experts have come down heavily on the BBMP's practice of diverting untreated sewage into downstream lakes. “Every lake must have an STP to treat all the sewage that it receives from upstream. This is the only way to decentralise sewage treatment. What BBMP has been doing is very myopic and only shifts the sewage load downstream, which is unscientific. BBMP has powers to sanction projects up to ₹3 crore, which is the reason why all projects are being designed within that limit, without any discussion with the BWSSB,” said S. Vishwanath, a water conservation expert.
