City's oldest STP in Vrushabhavathi underutilised: Study

City's oldest STP in Vrushabhavathi underutilised: Study

A recent study by researchers from Ashoka Trust for Research in Ecology and Environment (ATREE) reveals that the oldest sewage treatment plant of Bengaluru at Vrushabhavathi valley is not serving the purpose of treating waste water completely.

The study titled ‘contribution of sewage treatment to pollution abatement of urban streams’ showed that Vrushabhavathi Valley Treatment Plant (VVTP) was not being used to full capacity because of which untreated sewage water containing heavy metals, chemicals, detergents and industrial pollutants was entering Byramangala tank, water from which is used by farmers for cultivation of crops.

The study - conducted by Priyanka Jamwal, T Mohammed Zuhail, Praveen Raje Urs, Veena Srinivasan and Sharachchandra Lele from Centre for Environment and Development, ATREE - concentrated on the VVTP installed in the 1980s at Rajarajeshwari Nagar arch.

This means that the vegetables and milk produced in the area are contaminated.
The aim of the study was to ascertain how effective the STP was in addressing problems. Water samples were collected upstream and downstream and from inlets and outlets of VVTP.

The stream flow was measured and samples were analysed for physical, chemical and biological parameters, Veena explained. Sewage is let into the valley from the western part of the City including Malleswaram, Rajajinagar, Basavanagudi, central parts of the City and Mysuru Road. But these lines bring only 26-30 MLD to the treatment plant. It is treating the 26 MLD sewage along with diluted sewage coming from stormwater drains directly into the valley, which is 105 MLD.

Thus at any given time, 130 MLD of diluted sewage is processed by the treatment plant (though its capacity is 180 MLD).

The treatment plant is fit for handling raw sewage, so there is a need to improve the network so that sewage in full capacity enters the treatment plant, researchers said.

A need is also felt to increase the total installed capacity of STPs in the City. The government should give greater priority to connecting existing STPs to underground sewers and improving the efficiency of STPs, Veena said. 

Capacity count

The STPs in
Vrushabhavathi valley
Nalasandra    20 MLD
Kempambudhi    1 MLD
Nagasandra    75 MLD
VVTP    180 MLD
(According to BWSSB
officials, at any time the
 STPs work at 80% of
their capacity)