Polluted Hebbagodi Lake gets a second chance at life

Strike out from your memory the image of Hebbagodi Lake covered with sludge, weeds and plastic waste. Today, the lake boasts clean water, a children’s park and an RO drinking water unit.

Biocon Foundation, the CSR arm of Biocon and Syngene International Ltd, has bio-rejuvenated the 35-acre lake in southern Bengaluru, leading to an improvement in the water quality and the return of flora and fauna. The project was launched following approvals from the Karnataka Lake Conservation and Development Authority (KLCDA) and other government bodies.

Before that, the lake was largely covered with invasive weeds. Garbage and sludge had accumulated in it over the years, leading to a foul smell.

The revival efforts began in 2016 with a feasibility study of remediation techniques for the lake’s revival.

The next step was weeding the lake, composting the uprooted weeds and using the resultant green cover for landscaping around the lake. Several bar screens were then installed at the inlets to prevent fresh garbage from entering the lake. Thereafter, the 1.5-km lakebed was strengthened with native plants such as Vettiver (camel grass) to prevent soil erosion. The last step was fencing the lake.

What’s bioremediation?

Under bioremediation, the lake was dosed with a blend of enzymes and microorganisms to rapidly digest organic pollutants.

Multiple energy-efficient cascading aerators and submersible mixers were installed in the lake to enhance the level of dissolved oxygen in the water.

Floating wetlands were deployed for the continuous natural cleaning process.

Getting labourers for the rejuvenation was a big challenge. As the lake is located in the middle of Hebbagodi, the narrow roads obstructed sand and material trucks. Workers encountered snakes in the lake.

Sewage plant a must

The lake, however, may get polluted again with the inflow of untreated sewage. Biocon Managing Director Kiran Mazumdar-Shaw said a sewage treatment plant needed to be installed at the lake or else the whole revival effort would go waste.

“We are ready to set up the plant if the government permits it,” she said.

“We chose Hebbagodi Lake to do our part to our community first. We will focus on Bommasandra and Kammasandra lakes in future.”

The road to revival

* Lake size: 31 acres and 39 guntas

* Lake inlets: 5 sewage inlets and 2 stormwater inlets

* Sewage inflow: 2 million litres per day

*Total area of floating wetland: 12,000 square feet

*Total volume of soil used for the bund: 67,000 cubic metres

*Total volume of bio-enzymes dosed: 3,000 litres per day