Wetland system to handle excess sewage at Jakkur Lake in Bengaluru

Jakkur Lake in Bengaluru implements a wetland system to effectively treat excess sewage and restore water quality.

What used to enter Jakkur Lake as untreated sewage, turning parts of the water black, foul-smelling, and unfit for aquatic life, is now being cleaned through a wetland system, designed to treat excess wastewater that existing infrastructure cannot handle.

The change was made as the lake, despite having a Sewage Treatment Plant (STP), continued to receive ‘additional’ untreated sewage, especially through one of the three inlets — the northern inlet. With no immediate scope to expand the STP, North Corporation Commissioner Pommala Sunil Kumar told The Hindu that they have diverted this excess sewage into a wetland that treats the water in stages.

Akshath M.N., Assistant Executive Engineer (AEE) for Lakes, North Corporation, explained that the lake receives both treated water and untreated sewage through the storm-water drain. To manage this, the inflows were first segregated, and treated water is allowed to enter the main lake directly, while untreated sewage is diverted through the constructed wetland for further treatment.

Before the formation of the GBA, the bund remained incomplete. The bund is now fully developed, and a walkway was constructed over it. Mr. Akshath said that while an existing STP at the site has a capacity of 22 million litres per day (MLD), the volume of sewage being received exceeds this by an additional 7 to 8 MLD. This excess sewage is diverted into the wetland system.

A view of Jakkur lake in Bengaluru. | Photo Credit: ALLEN EGENUSE J.

“The wetland acts as a supplementary treatment mechanism, ensuring that the sewage passing through it undergoes natural treatment. As a result, by the time the water exits the wetland, pollution indicators such as Biological Oxygen Demand (BOD) are reduced compared to the levels at the inlet,” he added.