The need for wastewater management in India has intensified in recent years, with rapidly expanding urban areas generating far more sewage than the existing infrastructure can reliably collect, treat or safely discharge. Despite significant investments in large-scale sewage treatment plants (STPs) and trunk sewer networks, over 70 per cent of the country’s wastewater remains untreated, particularly in peri-urban areas, industrial pockets and high-altitude or complex terrains. These are areas where sewer networks are difficult and costly to build, and ageing wastewater infrastructure, along with stressed rivers, is highlighting the shortcomings of centralised wastewater infrastructure.
In this context, decentralised wastewater management (DWWM) has emerged as a critical pathway for India. Offering modularity, lower life cycle costs, faster deployment, and resilience against terrain and climate constraints, decentralised systems enable on-site wastewater treatment directly at the point of generation. With DWWM and river revitalisation initiatives picking up pace, technological innovations in compact STPs, nature-based systems and plug-and-play technologies are positioning decentralisation as a critical complement to traditional centralised wastewater infrastructure. Together, these factors showcase the need for a hybrid and strategically planned wastewater framework that integrates decentralised systems into India’s broader wastewater management agenda.
DWWM and river rejuvenation initiatives
Decentralised wastewater treatment is rapidly gaining traction in India, with cities like Delhi making substantial progress. As Delhi confronts rising sewage loads, uneven sewer coverage, water pollution in the Yamuna river and the limitations of centralised infrastructure, massive investments and initiatives for DWWM are emerging as a critical pillar of the city’s urban wastewater strategy.
The push towards decentralisation picked up pace in Delhi in April 2025, when the Expenditure Finance Committee approved Rs 31.4 billion for the development of 27 decentralised sewage treatment plants (DSTPs) and associated sewer infrastructure aimed at cleaning the Yamuna river in Delhi. This marks one of the earliest large-scale, coordinated efforts to mainstream decentralised treatment within Delhi’s river-cleaning ecosystem.
Building on this momentum, a major milestone was marked in August 2025 when the Delhi Jal Board (DJB) approved a substantial investment of Rs 6 billion to construct 11 DSTPs to support the rejuvenation of the Yamuna river. In the Najafgarh drainage zone, DSTPs will be paired with sewage pumping stations in Kair, Kanganheri, Kakrola and Dichaon Kalan under a Rs 2.84 billion package with 15 years of operations and maintenance (O&M), signalling a shift from isolated pilots to systematic zone-specific planning.
Meanwhile, DWWM is also advancing in Thiruvananthapuram, Kerala, with the installation of two DSTPs at Mathipuram Colony and Vizhinjam Harbour in November 2025. Implemented through a collaboration involving the Thiruvananthapuram Municipal Corporation, the Kerala Development and Innovation Strategic Council, the Kerala Institute of Local Administration and Social Alpha under the Innovations in Sustainable Urban Transition initiative, these systems will help streamline and enhance wastewater management in the city.
Under a broader river rejuvenation roadmap for the Yamuna river and renovation of Delhi’s wastewater infrastructure, the DJB formulated a comprehensive Rs 100.87 billion plan in June 2025. Drain management is another critical element of this river rejuvenation plan. Of the 22 drains discharging into the Yamuna, nine have been fully tapped as of June 2025, while the rest are at various planning stages. In parallel, the interceptor sewer project was completed in December 2025, enabling the treatment of 1,100 million litres per day (mld) of sewage through decentralised systems and significantly reducing water pollution in the Najafgarh drain. These developments mark a clear and accelerating shift towards decentralised wastewater treatment.
Sustainable initiatives for industrial wastewater treatment
India’s industrial wastewater sector is steadily adopting innovative technologies that are advancing sustainable wastewater and waste management, supported by recent research and development (R&D) breakthroughs in resource recovery and pollution reduction. For instance, in December 2025, researchers at the National Institute of Technology (NIT) Rourkela developed a nature-based, low-cost, chemical-free and energy-efficient constructed wetland-microbial fuel cell system to treat laundry wastewater. Designed for decentralised deployment, the system is scalable and particularly suited to densely populated dhobi ghats in cities like Mumbai and Bengaluru. A pilot at NIT Rourkela’s own dhobi ghat, which generates around 1,400 litres of laundry wastewater daily, showed effective removal of surfactants and chemical oxygen demand (COD) levels compliant with Bureau of Indian Standards norms. Using two cylindrical constructed wetland units integrated with microbial fuel cells, the system converts detergent-rich wastewater into odourless, colourless water fit for reuse, demonstrating strong potential for laundry wastewater recovery. Alongside, in December 2025, researchers at IIT Bhilai pioneered a sustainable polymer technology that transforms toxic industrial sulphur waste into advanced materials capable of removing hazardous pollutants from water. By coupling waste mitigation with material innovation, the technology exemplifies a circular economy model, offering a scalable and environmentally responsible solution to industrial sulphur management.
Earlier, in another significant breakthrough, in May 2025, researchers at Nagaland University developed a nature-based, biotechnology that reimagines wastewater as a source of reusable water, bioenergy and nutrients. Through the integration of algae-based treatment, microbial fuel cells and constructed wetlands, the system mimics natural processes to break down contaminants while recovering valuable by-products.
Meanwhile, emerging private sector start-ups are being encouraged to advance innovative industrial wastewater treatment techniques and methods. A recent example is the development of an innovative and sustainable industrial wastewater treatment technology by JSP Enviro, a start-up incubated at IIT Madras, in September 2025. This bioelectrochemical anaerobic digester system delivers cost savings, energy recovery and carbon emission reduction for industries across India, which are grappling with the dual challenge of managing wastewater and reducing the carbon footprint. Successfully deployed in Tamil Nadu’s Erode and Perundurai industrial units, the system exemplifies a shift towards localised, circular and climate-resilient wastewater management, providing scalable solutions for areas underserved by centralised industrial wastewater infrastructure.
Technology-driven initiatives
Technological innovation in decentralised and advanced wastewater management is rapidly gaining traction in India, driven by widening treatment gaps, stricter regulatory demands and a growing emphasis on resource-efficient water systems. Municipal authorities are increasingly adopting data-driven approaches to enhance oversight, collecting and analysing key wastewater parameters such as biological oxygen demand and COD. Reflecting this trend, the Pune Municipal Corporation announced in December 2025 its plan to map STPs within private housing societies using supervisory control and data acquisition systems. This will enable real-time monitoring, improve operational efficiency and support proactive infrastructure management.
Beyond urban centres, technology-driven interventions are addressing critical wastewater treatment shortfalls in ecologically sensitive and challenging terrains. Aligning with this, the National Mission for Clean Ganga has proposed the deployment of Japan’s Johkasou decentralised sewage treatment technology in Kedarnath, Uttarakhand, in September 2025. The system is proposed for 155 fixed toilets that currently rely on soak pits and cannot be connected to the under-construction 600 kilolitres per day capacity centralised STP. While the main STP is about 85 per cent complete, progress has been hampered by harsh terrain, extreme weather and limited labour availability. In this context, Johkasou offers a practical solution due to its compact, modular design and ability to treat wastewater at source.
Complementing these developments, decentralised technology solutions are also demonstrating tangible impact in urban settings. A DSTP installed in Singanallur, Tamil Nadu, in April 2025 by the Coimbatore-based NGO Siruthuli, used Apta Xblu compact treatment technology and has shown notable results. Set up on just 200 square feet of land, the STP unit has the capacity to treat up to 1 mld of sewage. The technological intervention has improved water quality in the city within six months and eliminated odour with minimal on-site requirements. Following the successful pilot, the technology is set to be replicated across other parts of the city to support wastewater-quality restoration and curb water pollution flowing into the Noyyal river.
Navigating future strategies
Going forward, India’s wastewater transition must move decisively towards a hybrid model that strategically combines centralised infrastructure with agile, decentralised systems capable of responding to rapid urbanisation, uneven sewer coverage and rising industrial loads. With only 28 per cent of wastewater currently treated, despite industrial wastewater volumes growing at nearly 8 per cent annually, the limitations of traditional, infrastructure-heavy systems are becoming increasingly evident. Large centralised STPs and trunk networks remain essential, but they cannot alone keep pace with fragmented growth, stressed river systems and the operational constraints faced in hilly, peri-urban and unsewered regions.
Consequently, DWWM needs to be mainstreamed into city sanitation plans, enabling wastewater to be treated and reused closer to the source. This requires clear technical standards, robust O&M frameworks and the integration of digital monitoring to ensure consistent performance across distributed assets. Alongside, private sector participation will be central to this shift. To this end, the Ministry of Housing and Urban Affairs has launched the second cohort of start-ups in the sanitation and waste management sectors in November 2025, under the Swachh Bharat Mission-Urban. About 32 start-ups have been onboarded under the second cohort to accelerate clean, innovative and tech-driven urban solutions. They have already delivered measurable outcomes, such as treating over 30 million litres of wastewater. At the municipal level, in November 2025, the Bengaluru Water Supply and Sewerage Board opened its STPs to water technology start-ups to catalyse R&D under the Brand Bengaluru initiative. Pilots such as Boson Whitewater’s installation of its advanced purification systems at the Kadubeesanahalli STP are supporting circular water economy by supplying high quality treated water to the city.
In parallel, blended finance, outcome-based incentives and targeted support for modular and nature-based systems hold the potential to help streamline decentralised treatment in underserved urban, peri-urban and rural areas. With enhanced R&D, capacity-building for urban local bodies and community participation, decentralised wastewater systems can move from being gap-fillers to becoming strategic components of India’s water security architecture. Collectively, these strategies will catalyse a pivotal shift, positioning decentralised wastewater management as a foundational element of a resilient, circular and future-ready wastewater ecosystem.
Aditi Gupta
