Bengaluru's Major Sewage Infrastructure Overhaul Underway
In a significant push to modernize its sewage management infrastructure, the Bengaluru Water Supply and Sewerage Board (BWSSB) has embarked on an extensive rehabilitation program targeting multiple sewage treatment plants (STPs) across the city. This initiative focuses on enhancing both the capacity and operational efficiency of existing facilities in the East and West zones, directly addressing the critical gap between sewage generation and treatment capacity in India's tech capital.
Comprehensive Rehabilitation of Existing Plants
Of Bengaluru's 34 operational sewage treatment plants, 20 have been identified for comprehensive rehabilitation under the stringent norms established by the National Green Tribunal. Seven of these projects, with a combined budget of approximately Rs 33.4 crore, are expected to reach completion by the end of this calendar year. The rehabilitation efforts span plants in key locations including Shivajinagar, Mahadevapura, KR Puram, and Dasarahalli, with treatment capacities ranging from 2 million liters per day (MLD) to 60 MLD.
In the East zone, four plants are undergoing substantial upgrades: the Ulsoor facility (2 MLD), Kadugodi plant (6 MLD), K&C Valley installation (60 MLD), and Yellamapalya unit (15 MLD). Meanwhile in the West zone, three major facilities are being rehabilitated: Chikkabanavara (5 MLD), Seegehalli–K&C Valley (40 MLD), and Nagasandra (20 MLD).
Meeting Stringent Environmental Standards
BWSSB Chairman Ram Prasanth Manohar emphasized that the rehabilitation essentially involves upgrading older sewage treatment plants to comply with the revised standards mandated by the National Green Tribunal in 2018. "Earlier, the treated water BOD level was 20 mg/l, which has now been reduced to 10 mg/l. Similarly, COD has come down from 250 mg/l to 50 mg/l, while total nitrogen is now capped at 10 mg/l and total phosphorus at 1 mg/l. The pH range remains between 6.5 and 8.5," Manohar explained.
To achieve these significantly tighter parameters, engineers are implementing a crucial addition to the treatment process: a tertiary treatment stage. While maintaining the conventional system comprising primary clarifiers, aeration tanks, and secondary clarifiers, technicians are installing disc filters that serve as a physical filtration step before chlorination. This enhancement dramatically improves the final treated water quality. Notably, these brownfield projects are being executed in carefully planned phases to avoid operational shutdowns, presenting unique engineering challenges.
New Plants for Growing Urban Demand
Parallel to the rehabilitation efforts, BWSSB is simultaneously developing new sewage treatment plants in the CE (Project) zone to accommodate Bengaluru's expanding urban settlements. These new facilities, strategically located in areas including Jakkur, Pillaganahalli, Thalagattapura, Hemmigepura, Sampigehalli, and Nagasandra, feature capacities ranging from 4 MLD to 13 MLD.
Each new plant represents a substantial investment, with project costs varying between Rs 10 crore and Rs 39 crore. Designed specifically to meet escalating sewage treatment demands in rapidly developing localities, these facilities are projected to become operational by 2028. Construction progress has already approached 100% completion at some sites, with financial expenditures tracking appropriately toward timely project finalization.
Addressing Bengaluru's Sewage Management Challenge
According to the Economic Survey of Karnataka 2025-26, Bengaluru's urban population of nearly 1.5 crore generates approximately 1,480 million liters of sewage daily. The city currently relies on 34 STPs with a total installed capacity of 1,348.5 MLD, of which 1,212.7 MLD of wastewater receives treatment. This reveals a significant gap between sewage generation and available treatment capacity that the current infrastructure initiatives aim to bridge.
The current distribution of treatment capacity across drainage zones includes:
- Challaghatta Valley: 518.5 MLD across 9 plants
- Koramangala Valley: 207 MLD across 8 plants
- Hebbal: 278 MLD across 11 plants
- Vrishabhavathy: 345 MLD across 5 plants
Officials anticipate that the inauguration of both rehabilitated and new sewage treatment plants will substantially bolster Bengaluru's sewage management capabilities. This infrastructure enhancement promises cleaner waterways and improved environmental compliance for the city's continuously expanding population, marking a critical step toward sustainable urban development.
