FAQ: Water circularity in India

Water circularity refers to the practice of recycling and reusing water multiple times and recovering valuable resources from it, instead of a linear “use-and-dispose” approach. In a circular water economy, used water (such as municipal sewage or industrial effluent) is treated and returned to the system for various purposes (irrigation, industry, groundwater recharge, etc.), thus maximizing the value of each drop and minimizing waste. This approach reduces pollution, eases pressure on freshwater sources, and helps regenerate natural water systems.

For India, circularity is a necessity. With 18% of the world’s population but only 4% of its freshwater, the country faces extreme water stress. NITI Aayog warns that by 2030, water demand could double the available supply. Currently, groundwater is over-extracted and rivers are increasingly polluted. Climate change further destabilizes this fragile balance through erratic monsoons and droughts. Currently, urban India generates over 72,000 MLD of sewage, but over 70% is discharged untreated. Circular water management seeks to "turn waste to worth" by treating this sewage for safe reuse. This transition not only addresses the clean water shortage but also extracts organic fertilizers and biogas, supporting India’s broader sustainability and climate goals.

India’s regulatory landscape for water circularity is evolving through a mix of national mandates and proactive state policies. Key frameworks include:

National Policies and Mandates

The Ministry of Jal Shakti mandates that cities recycle at least 20% of their water. In 2022, the National Mission for Clean Ganga (NMCG) released a "National Framework on Safe Reuse of Treated Water," providing a roadmap for business models and standards. Sector-specific rules, like the Tariff Policy 2016, force thermal power plants within 50km of a city to use treated sewage for cooling. Additionally, CPCB effluent standards and "Zero Liquid Discharge" mandates push industries toward internal recycling.https://susbio.in/the-future-of-wastewater-treatment-in-india-policy-directions-and-innovations/

State-Level Leadership

Several states have set ambitious targets that exceed national guidelines:

• Gujarat: Aims for 100% reuse of treated wastewater by 2030.

• Haryana: Prioritizes treated water for power plants and industry over freshwater.

• Maharashtra & Tamil Nadu: Mandate recycled water for urban industries and have updated building codes to require rainwater harvesting and dual-piping.

• Karnataka & Rajasthan: Have integrated wastewater reuse into their formal state water resource management plans.

Local Bylaws and Standards

At the municipal level, cities like Bengaluru and Pune require large housing complexes to install on-site STPs and dual-plumbing systems. To ensure safety, the Bureau of Indian Standards (BIS) and CPCB have established "fit-for-purpose" quality grades, defining safe parameters for using treated water in agriculture versus industrial cooling.

Implementing water circularity in India faces significant infrastructure hurdles across urban, rural, and industrial landscapes. Here is a summary of the primary challenges:

The Treatment Gap (Urban): India currently treats only about 28% of its 72,000 MLD of urban sewage. This is largely due to a lack of comprehensive underground sewer networks; without universal collection, wastewater never reaches treatment plants. Furthermore, many existing Sewage Treatment Plants (STPs) operate below capacity due to poor maintenance or erratic power supply. Closing this gap to reach 100% treatment by 2047 will require an estimated USD 18–27 billion in capital investment.

Missing "Last-Mile" Distribution: A major barrier is the lack of reuse networks (often called "purple pipelines"). Even when water is treated, cities rarely have the separate piping systems needed to deliver it to industrial hubs, parks, or farms. Retrofitting dense urban areas with dual distribution lines is logistically difficult and expensive. Without these dedicated storage and delivery systems, treated water is simply discharged back into polluted rivers.

Quality Control and Technical Standards: Different reuses require different levels of purification (e.g., industrial boilers need higher quality than city parks). Most Indian STPs provide only secondary treatment; upgrading to tertiary treatment (advanced filtration and disinfection) is costly. A shortage of skilled operators and lab facilities also makes it difficult to maintain the consistent water quality needed to build trust among end-users like farmers and factory owners.

Rural and Industrial Constraints

• Rural gaps: Most villages lack basic drainage or sewage systems. Transitioning to circularity requires building decentralized, low-cost infrastructure (like constructed wetlands) across 600,000 villages, which demands significant community training and funding.

• Industrial effluents: While large plants often adopt Zero Liquid Discharge (ZLD), these systems are energy-intensive and expensive for Small and Medium Enterprises (SMEs). Managing the hazardous by-products of treatment, such as RO brine and toxic sludge, remains a persistent infrastructure challenge.

To bridge the massive funding gap for water circularity, India is moving beyond traditional government budgets toward a mix of private capital and market-based mechanisms. Key financing strategies include:

Public Grants and State Programs

Government missions like AMRUT 2.0, Namami Gange, and the Jal Jeevan Mission provide the foundational capital for treatment plants and sewer networks. The 15th Finance Commission has also tied specific grants for Urban Local Bodies (ULBs) to their performance in wastewater management, incentivizing cities to prioritize reuse.

Public-Private Partnerships (PPP) & Hybrid Models

To improve efficiency, India uses the Hybrid Annuity Model (HAM). In this setup, the government pays 40% of the capital cost, while the private developer covers the rest, recovering it through 15 years of performance-linked annuity payments. This ensures long-term maintenance rather than just construction. Other models, like.

Build-Operate-Transfer (BOT), are used in cities like Nagpur to sell treated water to power plants, creating a revenue-sharing system for the municipality

Several Indian cities and villages have successfully transitioned to water circularity, proving that wastewater can be a high-value resource. Here are the most notable case studies:

Nagpur, Maharashtra: Industrial Power Cooling

Nagpur is a national pioneer in urban-to-industrial reuse. The city treats 130 MLD of sewage to a tertiary level and sells it to the MahaGenCo thermal power plant for cooling.

• The impact: This frees up enough freshwater to supply 1.5 million people.

• The revenue: The city earns approximately ₹15 crore annually, covering its infrastructure costs. This "Nagpur Model" influenced the 2016 National Tariff Policy, which now mandates that all thermal plants near cities use treated wastewater.

Integrating water circularity into agriculture and manufacturing—India’s two largest water consumers—is essential for national water security. Here is how these sectors are adopting circular models:

Integration with Agriculture: "Fertigation" and Resilience

Agriculture consumes ~80% of India’s freshwater. Using treated municipal wastewater provides a drought-proof alternative for farmers.

• Nutrient Recovery: Treated sewage is rich in nitrogen, phosphorus, and potassium. Using it as "fertigation" (fertilizer + irrigation) can increase farmer income by roughly ₹17,000 per hectare annually due to higher yields and reduced chemical fertilizer costs.

• Resource Savings: Substituting wastewater for groundwater could save an estimated 1.75 million MWh of electricity annually by reducing the need for deep-well pumping.

• Examples: Projects like the one in Kolar (using Bengaluru's treated water) have successfully recharged aquifers and doubled farmer incomes.

• Safeguards: To manage health risks, India is developing standards to restrict reuse to non-food crops (fodder, orchards) and implementing drip irrigation to minimize contact with pathogens.

Integration with Manufacturing: Zero Liquid Discharge and Symbiosis

Industries are shifting from "consumers" to "recyclers" to meet strict regulations and ensure operational continuity.

• Zero Liquid Discharge (ZLD): In highly polluted sectors like textiles (Tirupur) and chemicals (Vapi), the government mandates ZLD. These plants use ultrafiltration, reverse osmosis, and evaporators to recover and reuse nearly 95-100% of their water.

• Internal Efficiency: Thermal power plants use ash-water recirculation and cooling tower recovery. A typical plant can save 10 million m³ of water and ₹30 crore annually through these measures.

• Industrial Symbiosis: This involves industries using municipal treated water instead of freshwater. For example, power plants in Nagpur and industries in Chennai purchase treated city sewage, creating a "win-win" where cities earn revenue and industries secure a reliable supply.

Emerging Technologies

• Membrane Bioreactors (MBR): Compact, high-efficiency systems that produce high-quality water for immediate reuse in factory processes.

• Digital Monitoring (IoT/AI): Indian plants are adopting AI-based monitoring to detect leaks and optimize cooling tower cycles in real time, significantly reducing water withdrawal.

Emerging technologies are transforming water from a "disposable" resource into a renewable asset in India. These innovations focus on making treatment higher-quality, decentralized, and digitally optimized.

Advanced Membrane & Biological Treatment

Modern plants are moving beyond basic filtration to produce high-purity water:

• MBR (Membrane Bioreactors): Integrates biological treatment with membrane filtration. It offers a smaller footprint and superior effluent quality, making it ideal for space-constrained Indian cities.

• Advanced Filtration (UF/NF/RO): Used in "Tertiary Treatment" (like Chennai’s TTRO plants) to remove pathogens and dissolved salts, making wastewater safe for industrial and even indirect potable use.

• SBR (Sequencing Batch Reactors): A high-efficiency oxygen-based treatment increasingly used in new municipal plants to ensure consistent water quality.

Decentralized & Nature-Based Solutions

Instead of massive, distant plants, circularity is moving closer to the source:

• Modular STPs: Compact, "plug-and-play" systems (using MBBR technology) allow housing complexes and malls to treat and reuse greywater on-site for flushing and gardening.

• Constructed Wetlands: Low-energy, nature-based systems use specific plants and soil microbes to treat wastewater. These are highly effective for rural irrigation and pond rejuvenation.

Digital Water: AI and IoT

The "Smart Water" revolution provides the data needed to make reuse safe and reliable:

• IoT Sensors: Real-time monitoring of pH, turbidity, and chemical levels ensures treated water always meets safety standards.

• AI-Powered Plants: Launched in 2025, India’s first AI-driven STPs automate aeration and chemical dosing. This reduces energy consumption and prevents the discharge of untreated water due to human error.

Energy-Efficient Innovations

To lower the high cost of recycling, India is exploring:

• Waste-to-Energy: Anaerobic treatment that captures biogas from sewage to power the treatment plant itself, moving toward "net-zero" energy facilities.

• Solar-Driven Treatment: Startups are developing solar-powered electrodialysis and desalination units to recycle industrial brine using renewable energy.

Smart Monitoring & Mapping

• Portable Kits: Handheld digital sensors allow for instant on-site testing of heavy metals and pathogens, building public trust in recycled water.

• GIS & Remote Sensing: Satellite data helps planners map "water-stressed" zones and identify the best locations to divert treated wastewater for irrigation.

Water stewardship is the collaborative management of water resources by industries, communities, and governments. Unlike simple efficiency, stewardship focuses on the health of the entire catchment area (watershed) to ensure long-term water security for all users.

In India, this is practiced through three primary pillars:

Corporate Water Stewardship: Large companies are moving beyond reducing their own consumption to becoming "water positive"—returning more water to the environment than they extract.

• Watershed Projects: Companies like ITC fund massive rural watershed development, including check dams and soil moisture conservation.

• Offsetting & Replenishment: Beverage giants (Coca-Cola, Pepsi) partner with NGOs to rejuvenate village ponds and install drip irrigation for local farmers to offset their bottling plant usage.

• Global Standards: Many follow the Alliance for Water Stewardship (AWS) framework, which coordinates collective action between factories, farmers, and local authorities within the same river basin.

Community & Civil Society Stewardship: India has a deep tradition of collective water governance where local users set rules for equitable sharing.

• Water Budgeting: Organizations like WOTR train villagers to measure rainfall and aquifer levels. The community then collectively decides which crops to plant based on available water, preventing over-extraction.

• Traditional Revival: Groups like Tarun Bharat Sangh have led communities in reviving thousands of traditional structures (johads/ponds) to restore dried-up rivers.

• Urban Lake Mitras: In cities like Bengaluru, citizen groups ("Friends of Lakes") monitor pollution and work with municipalities to maintain urban water bodies.

Multi-Stakeholder Partnerships & Policy: True stewardship requires a seat at the table for everyone—government, private sector, and citizens.

• Jal Shakti Abhiyan: A massive campaign where government agencies and CSR teams collaborate with volunteers on recharge pits and awareness programs.

• Namami Gange: The NMCG involves "Ganga Mitras" (citizen volunteers) and corporate funding to complement state-built sewage infrastructure with riverbank restoration.

• Policy Integration: Schemes like Atal Bhujal Yojana now mandate "community water budgets," operationalizing stewardship by requiring local approval for groundwater management.

Urban and rural water needs in India are hydrologically and socio-economically inseparable. Recognizing these linkages is vital to preventing conflict and ensuring regional water security.

Competition for Shared Sources

Cities and farms often draw from the same rivers and reservoirs. In India, many dams originally built for rural irrigation now prioritize urban drinking water.

• The Conflict: In drought years, diverting water to metros like Mumbai, Chennai, or Bengaluru can leave upstream farmers without irrigation, fueling social and legal tensions.

• The Interdependence: Scarcity in one sector inevitably impacts the other, making water management a regional—not just local—issue.

Upstream-Downstream Dynamics

Rural areas typically manage the upstream catchments that collect a city’s water. Conversely, cities discharge wastewater that flows downstream into rural lands.

• Pollution Impact: If a city fails to treat its sewage, downstream farmers suffer from contaminated crops and livestock.

• Source Protection: If upstream rural areas suffer from deforestation or chemical runoff, the city’s water quality and quantity are jeopardized. Holistic basin management is the only solution.

"Waste-to-Asset" Transfers (The Circular Link)

Urban-rural linkages offer a unique circular opportunity: cities can become water providers for the countryside.

• Feedback Loops: By treating urban sewage and pumping it back to rural areas for irrigation (as seen in the Bengaluru-Kolar project), cities reduce the pressure on fresh groundwater.

• Mutually Beneficial: This "recycled water for food" swap eases tensions and provides farmers with a reliable, nutrient-rich water source throughout the year.

Benefit Sharing and Policy

Newer frameworks emphasize that cities should compensate rural "stewards" for protecting the water supply.

• Payment for Ecosystem Services: Concepts are emerging where cities invest in rural watershed development (check dams, forestation) to secure their own future supply.

• Integrated Planning: India’s AMRUT 2.0 and SDG 11.A guidelines push for planning that considers the urban-rural hinterland as a single unit, ensuring that urban growth does not come at the expense of rural sustainability.

Advancing water circularity in India requires a dual approach: communities provide the social foundation and local buy-in, while Public-Private Partnerships (PPPs) supply the necessary capital and technical expertise.

Community-Led Initiatives (The Social Foundation)

Community involvement ensures that water projects are culturally accepted and locally maintained.

• Ownership and Maintenance: Grassroots participation prevents infrastructure from falling into disrepair. In Rajasthan, village committees manage revived johads (earthen dams), ensuring they remain desilted and functional for groundwater recharge.

• Behavioral Change: Communities are essential for overcoming the "yuck factor" associated with recycled water. Residents' Welfare Associations (RWAs) in cities like Pune have successfully championed the use of treated greywater for flushing and gardening through transparent dialogue.

• Accountability: Local "watchdog" groups, such as the Ganga Mitras, monitor river health and report untreated discharges, holding authorities accountable for maintaining treatment standards.

Public-Private Partnerships (The Economic Engine)

PPPs bridge the massive gap in funding and specialized skills required for large-scale recycling.

• Mobilizing Investment: Models like the Hybrid Annuity Model (HAM) under Namami Gange attract private firms by linking government payments to the actual performance and quality of treated water.

• Operational Efficiency: Private partners bring advanced technology (like AI and automation) and are often responsible for long-term maintenance (10–30 years). This ensures that plants don't just get built but continue to produce reuse-quality water for decades.

• Risk Sharing: PPPs transfer technical and financial risks to the private sector. In Nagpur, a 30-year BOT (Build-Operate-Transfer) contract ensures a steady supply of recycled water to power plants, providing the city with guaranteed revenue.

The Hybrid "PPCP" Model

The most resilient projects are moving toward Public-Private-Community Partnerships (PPCP). This model adds a community oversight layer to private contracts, ensuring that private efficiency does not come at the cost of public affordability or local needs.