Bengaluru: In a significant step towards sustainable waste management and revenue generation, the Karnataka government has cleared a proposal to convert sewage sludge into biogas, with an estimated earning potential of up to ₹120 crore annually.
The initiative, announced in the 2025–26 state budget, focuses on monetising nearly 200 tonnes of sludge generated daily from Bengaluru’s wastewater treatment plants by supplying it to private firms for biogas production.
Bengaluru currently operates 34 sewage treatment plants, which together process around 1,348.5 million litres per day (MLD) of wastewater. These facilities produce substantial quantities of sludge rich in organic material, making it suitable for biogas generation through anaerobic digestion.
As part of the first phase, sludge will be sourced from five major treatment plants—including two in KC Valley, Bellandur Amanikere, Vishveshwara Valley, and Hebbal Valley. These plants collectively handle about 550 MLD of sewage, providing enough raw material to launch the project at scale.
The project will be implemented under a Public-Private Partnership (PPP) model using a Design-Build-Finance-Operate-Transfer (DBFOT) framework. Under this arrangement, private companies will invest in setting up and running the biogas facilities, while the government will provide land within existing treatment plant premises. The agreement includes a 20-year concession period, with approximately one year earmarked for construction.
To ensure operational stability, the plan includes a penalty clause requiring BWSSB to supply the agreed quantity of sludge, ensuring consistent input for biogas production. This structure allows the government to avoid upfront investment while still generating revenue.
Officials estimate that the project could produce nearly 30,000 cubic metres of biogas per day, contributing significantly to clean energy generation. The proposal has been technically and financially evaluated by KPMG, strengthening its feasibility.
According to BWSSB chairman V Ram Prasath Manohar, the project is expected to become operational within six months, aided by its proximity to existing gas infrastructure, which will ease distribution and utilisation.
The initiative marks a broader push towards a circular economy model, aiming to reduce waste disposal challenges, generate renewable energy, and improve urban revenues. While the concept is relatively new in Karnataka, similar projects have already been implemented in other parts of India.
With this move, Bengaluru is set to transform its sewage system into a valuable energy resource, reinforcing its position as a frontrunner in urban waste-to-energy innovation.
