Experts call for adoption of circular sanitation model for wastewater management

As conversations around the circular economy gain momentum worldwide, sanitation experts at the World Toilet Summit-2025 in New Delhi said India cannot afford to treat wastewater and faecal sludge as an afterthought anymore. Toilets have reached millions of homes, they noted, but the country is still struggling with what happens after people flush, making it essential to recover resources, reuse water and rethink sanitation as part of a larger environmental cycle.

Speaking at a technical session at the India Habitat Centre on Wednesday, Praveena Gangadharan, Associate Professor at IIT-Palakkad, said India’s wastewater problem began with its dependence on septic tanks. Most households were not connected to sewer networks and treatment systems were unable to handle the volume of waste being generated. “Most of the wastewater we produce is discharged into water bodies untreated, and 80 per cent of water pollution is associated with poor septic sludge management,” she said.

She explained why India needed a mix of sewer-based, decentralised and non-sewer solutions instead of relying on one system.

India’s government has also been pushing for a shift toward circular sanitation, with schemes under Swachh Bharat Mission 2.0 emphasising faecal sludge and septage management, co-treatment at sewage treatment plants and reuse of treated wastewater for agriculture and industry.

Several states, including Uttar Pradesh, Himachal Pradesh, Maharashtra and Odisha, have begun piloting co-composting units, faecal sludge treatment plants and initiatives to convert waste into biofertilisers.

Her team has been working on simple, affordable ways to convert waste into something useful, recovering nitrogen and phosphorus from urine, producing fertiliser, and even generating small amounts of electricity.

From her field experience in Uttar Pradesh’s Hardoi district, Dr Amrita Dwivedi, Assistant Professor at IIT BHU in Varanasi, shared what circular sanitation looked like in practice. Women in self-help groups there manage composting pits, greywater and household waste, but still face social restrictions that limit how much they can participate in sanitation decisions.

One woman told her team, “We still handle the waste, but the decisions about it are taken elsewhere.” Dwivedi said empowering these women through training and microfinance support was essential if rural areas were to adopt circular sanitation systems meaningfully.

Adding an international perspective, Dr Devendra Saroj, Head of Centre for Environmental Health and Engineering, said human waste contains valuable resources that can reduce the pressure on chemical fertilisers.

Drawing on his work in the Philippines, he showed how septic sludge can be processed into clean water, biochar and ‘high-value fertiliser’ without requiring people to change their toilets. “Science has proven its potential. The challenge now is scaling technologies with all stakeholders on board,” he said.