Froth to fame: Bengaluru, Surat top national rankings for sewage treatment in metros

Bengaluru ranks second in India's sewage management, awarded ₹103 crore for 23 top-rated STPs, improving wastewater treatment since 2015.

Seven years after Bellandur Lake in Bengaluru made international headlines for frothing and catching fire due to unchecked dumping of untreated sewage and industrial effluents, the city has emerged as the second-best performer in sewage management in the country under a central government initiative. In March this year, the city was awarded ₹103 crore under the Jal Hi Amrit initiative for its effective sewage treatment. Of the 30 sewage treatment plants (STPs) evaluated in Bengaluru, 23 received a 5-star rating, six a 4-star rating, and one a 3-star rating.

Bellandur Lake, once infamous for frothing and fires, reflects Bengaluru’s strides in sewage treatment and water reuse. (PTI)

Surat, Gujarat’s Diamond City, topped the national rankings and was awarded ₹104.75 crore, with 19 out of 20 STPs rated 5 stars and one with 4 stars.

A 5-star rating denotes consistent performance in five key parameters: used water quality, renewable energy usage, innovative systems, monitoring mechanisms, and reuse of treated water. Four- and three-star ratings indicate satisfactory performance in four and three aspects, respectively.

S. Vishwanath, a Bengaluru-based water expert who advises several government and non-profit bodies, credited a 2015 National Green Tribunal (NGT) order for improving wastewater treatment in the city. “Treated wastewater is essential for the lakes in Bengaluru, as they are non-perennial. Thanks to the NGT order, the wastewater treatment quality has increased greatly due to the investments made by the government agencies,” he said.

“The full lakes are not only free of froth and fire but also recharge shallow aquifers, making the groundwater condition very stable,” he added. He said around 15 MLD of treated water is also being used for power generation in Jakkur, and some of it is sent to parched districts such as Kolar and Chikkaballapur.

However, Vishwanath noted that while treatment has improved, sewage collection and consistent monitoring of water quality remain areas of concern. “Once a system of treated water is in place, it can be utilised for agricultural, ecological, and industrial purposes as required,” he said.

While MoHUA did not disclose a complete ranking of states or cities, the agency confirmed that 250+ field assessors evaluated the STPs, and ₹400 crore was disbursed as incentives in the last fiscal. The ministry also highlighted the training of over 3,400 officials and 30 capacity-building sessions. A Water Resource Recovery Cell (WRRC) has been set up at the state level for ongoing monitoring and enhancing reuse and biosolids management.

Though Bengaluru has shown marked improvement, Surat’s success has been more consistent. A 2024 analysis by the Council on Energy, Environment and Water (CEEW), using public data, placed Surat and Bengaluru nearly neck-and-neck, with scores of 3.32 and 3.23 out of 5, respectively. No other city scored above 3, with 47 cities scoring between 2.25 and 3.

By the end of 2023, Surat was reusing 330 MLD of treated water, with 115 MLD supplied to textile processing industries, generating ₹140 crore in annual revenue. The city has set a target of 100% treated water reuse by 2030 and is the only Indian city on the Stockholm International Water Institute’s zero liquid discharge cities panel. MoHUA also lauded Surat’s Anjana STP for cost-effective capacity augmentation using the integrated fixed-film activated sludge (IFAS) process without disrupting operations. States and UTs have been advised to adopt similar models.

At the state level, Gujarat emerged as the top performer with ₹164 crore, followed by Maharashtra and Karnataka. Among Gujarat’s top cities, Ahmedabad received ₹48 crore for its 16 STPs (two 5-star, nine 4-star, and five 3-star), while Jamnagar was awarded ₹11 crore.

In Maharashtra, Navi Mumbai was recognised for its advanced water reuse and near-total penetration of underground sewage lines. It won an SKOCH award, an independent civilian honour, in March for supplying 50 MLD of treated water to industries and reserving freshwater for potable use.

Mayank Mithaiwala, a Surat-based STP expert, said the current industrial reuse of treated sewage in the state is based on the 2018 state government policy aimed towards conserving fresh water resources. At present, only 1100 MLD of treated sewage out of the total 3860 MLD is currently being reused, he said, adding that the reuse holds huge potential to save fresh water equivalent to serving more than two crore people.

“In times of climate change-induced change in rainfall patterns, it is necessary to arrange for novel water resources, and use of treated municipal sewage should be the new paradigm across India,” Mithaiwala said.

Despite these successes, MoHUA has not shared a city- or state-wise ranking list, nor released other macro-level insights. The Centre for Energy, Environment and Water (CEEW) in March 2024 ranked Bengaluru and Surat equally in a separate study. Their composite scores were 3.23 and 3.32 out of 5, respectively, based on 27 indicators across five themes: finance, infrastructure, efficiency, governance, and data. No other city scored above 3. Of 503 cities assessed, 47 scored between 2.25 and 3, and 151 between 1.5 and 2.25.

On March 27, the government told the Lok Sabha that just 3,531.52 MLD—or 28%—of the 12,599.28 MLD of sewage treated under the Atal Mission for Rejuvenation and Urban Transformation (AMRUT) mission 1 and 2 was fit for reuse across India’s cities.