Problem identification

Water security is crucial for the sustainable growth and resilience of economies. Managing freshwater demand should be India’s foremost priority in achieving water security, considering that 11 out of the 15 major river basins in the country will be water-stressed by 2025 (Bassi, Gupta, and Chaturvedi 2023). The situation is particularly severe in urban areas where scarce freshwater resources are unable to keep up with the growing water demand. Given the quantum of domestic used water generated in Indian cities, once safely treated and reused, it can serve as a highly valuable resource that can reduce the pressure on freshwater resources and improve the quality of rivers and aquifers. However, only 30 per cent of the domestic used water generated by Class I and II cities (population above 50,000) is treated (CPCB 2021). The remaining water is discharged into freshwater bodies such as rivers and lakes (Bassi, Gupta, and Chaturvedi 2023). This significantly contributes to water body pollution in India, especially in the stretches passing through urban areas.

Need for the solution

Although many Indian cities are implementing treated used water (TUW) reuse projects, the level of reuse is still very low overall, even in metropolitan cities. Out of the 503 urban local bodies (ULBs) assessed by a CEEW study, 414 do not reuse their TUW. Thane City is currently reusing 5 per cent of its TUW (Gupta et al. 2024). Being the paramount authorities responsible for domestic used water management, ULBs need to be empowered to formulate and adopt long-term reuse plans – with clear targets for used water treatment and reuse – an element currently missing in Indian cities.

Importance of the TUW Reuse Plan

The TUW Reuse Plan for Thane City was developed by CEEW in association with the Thane Municipal Corporation (TMC). This first-of-its-kind plan aims to maximise the safe reuse of TUW, enabling a circular economy approach to used water management in TMC. It promotes TUW reuse for non-potable purposes and establishes reuse – specific quality standards to ensure its reusability. This will reduce the city’s dependence on existing freshwater resources for non-potable purposes, optimise resource efficiency, and improve the water quality of local water sources in Thane City.

The Reuse Plan sets quantifiable targets for 2035 and 2046 for enhancing treatment capacity utilisation, upgrading existing treatment infrastructure – mainly treatment technologies – , and maximising the safe reuse of TUW for Thane City. Also, it proposes viable business models to scale up the reuse of water in different sewage zones in the city.  Local authorities must align their efforts and resources towards achieving these time-bound benchmarks. For the development of the plan, over 20 consultations were conducted with TMC officials (Figure 2a–e).

Figure 2a–e: Consultation workshops and meetings with TMC officials

a)      CEEW team presenting the reuse plan to the Municipal commissioner of TMC

b)     Consultation with various line departments within TMC

c)      CEEW team briefing TMC officials about the training and assistance needs assessment exercise

d)     CEEW team visiting the Kopri STP for consultations with engineers

e)     CEEW team presenting the TUW Reuse Plan (Draft) to the TMC Commissioner for review and feedback