Bangalore Water Supply and Sewerage Board (BWSSB), Karnataka, India – In construction reservoir augmentation

Water scarcity is a challenge facing Bengaluru (Bangalore), India’s IT hub and a city of more than 13 million people. There has been an over-dependence on the main water source, the River Cauvery, which is far away and relies on monsoon rains. There has also been over-exploitation of groundwater resources, and significant pollution of urban water areas.

The water utility, Bangalore Water Supply and Sewerage Board (BWSSB) is addressing this challenge with innovative solutions. BWSSB currently has a water supply system of 1450 million litres (380 million gallons) a day and is further augmenting the system by another 775 million litres (200 million gallons) a day which is expected to be ready by December 2024. However, BWSSB has a target to augment their water source to 3,000 million litres (790 million gallons) per day by end of 2026-27, so there remains a gap. Hence BWSSB developed a Total Water Management strategic initiative, which embodies circular economy objectives, and set a target to capture 90% of the wastewater generated in the city by 2025.

As a part of the initiative BWSSB has taken up the TG Halli 110 million litres (29 million gallons) per day Reuse Project as a pilot for an alternate source of supply. The TG Halli reservoir (with a capacity of 209 million litres, or 55 million gallons per day) of BWSSB has dried up due to rapid urbanisation in the surrounding areas. The reservoir presently is being augmented by 93 million litres (24 million gallons) per day of raw water (rainwater cum river water) from Yethinahole, a tributary of the Nethravati River, from a distance of 350 km. This 1.2 TMC augmentation of raw water is done by the Irrigation Department.

The TG Halli project implemented by BWSSB commenced in 2019 and is expected to be operational by end 2024. Under this project BWSSB is constructing a 20 million litres (5 million gallons) per day Sewage Treatment Plant. The secondary treated water from this Sewage Treatment Plant is blended into the TG Halli Reservoir. The TG Halli reservoir has been dredged of 1.23 billion kilograms of silt under this project. It also includes construction of a 110 million litres (29 million gallons) per day Water Treatment Plant with Ozonization. Hence the project will finally producd 110 million litres (29 million gallons) of re-use water and rainwater which is used for indirect potable reuse.

Over time such projects are expected to be enlarged, to a total capacity of 600 million litres (158 million gallons a day), in around the 2040s.