A State government report on the clean-up of Bengaluru’s two beleaguered lakes — Varthur and Bellandur — to the National Green Tribunal (NGT) showed that sewage from apartments form a minuscule part of the total sewage entering Bellandur lake.
The report, signed by six government agencies, states that while 480 million litres of sewage was entering Bellandur lake daily, the contribution from apartments was 66.87 MLD.
Of the 755 apartments in the Bellandur catchment area inspected by the Karnataka State Pollution Control Board (KSPCB), 390 have sewage treatment plants (STPs) installed. In all, states the report, 48.19MLD was being treated through STPs installed in apartments, while just around 13.66 MLD was being discharged into the sewage system.
“Sewage from smaller projects (not covered under consent mechanism by KSPCB) are generating enormous quantity of sewage, including individual houses,” notes the report.
Srikanth Narasimhan, general secretary, Bangalore Apartments’ Federation, says the report makes it clear that apartments are not the cause of the mess. “Apartments either have set up STPs or are connected to the underground sewage network provided by BWSSB (Bangalore Water Supply and Sewerage Board). Even then, only 2.8% of the sewage in the underground drainage (UGD) network is coming from apartments with the rest from individual houses and small buildings,” he said.
While BWSSB has made it mandatory to install STPs in apartments with more than 50 units by the end of the year, KSPCB is issuing notices to apartments with 20 units or more.
However, Lakshman, chairman, KSPCB, said their notification was enforced in 2016, after a gap of six years during which it was suspended. “This is applicable to the Bellandur catchment area, and we are implementing it retrospectively for any apartment with 20 dwelling units or more which has come up after 2010,” he said.
He said that while BWSSB continues to be the primary target, apartments do form a “significant” part. “This is as much a precautionary measure. Even if it is a low percentage, it can go a long way in reducing the sewage load. After all, tackling 64 MLD from these apartments will definitely improve the situation in Bellandur lake too,” he said.
No clean up before 2020
The report submitted by the State government agencies to the National Green Tribunal (NGT) says that a clean-up of Bellandur lake can be possible only after 2020, when raw sewage inflow is expected to stop.
The estimated ₹550-crore one-time cleaning of the lake, including dewater and dredging, is “futile” if the sewage continues to flow into the lake, the report quotes the opinion of expert committee members.
“However, if the Honourable Tribunal feels that this time frame is too long, then the second best option would be to wait till December 2017 by when the inflow of untreated sewage is likely to come down to below 100 MLD from two inlets of Koramangala and Iblur,” states the report.
It is only after the completion of one-time cleaning measure that aerator systems can be installed. This, shows the report, will take 12 months additionally and over ₹34 crore.