SAFETY IN CIRCULARITY

Global standards of water availability show that India is water stressed. Reusing treated wastewater can augment water supply while solving the problem of its safe disposal. FARAZ AHMAD and SUMITA SINGHAL analyse wastewater management practices of 16 cities in seven states to understand the challenges and potential areas of reuse

- FARAZ AHMAD and SUMITA SINGHAL

INDIA IS a parched nation. With an annual per capita freshwater availability below the international threshold of 1,700 cubic metres (m³), India ranks 132nd in the world with respect to per capita water availability. This makes the country "water stressed".

Between 1950 and 2024, there has been a decline of 73 per cent in per capita surface water availability in the country, as per the Union government's India Water Resource Information System (see 'Surface water scarcity' on p40). If no steps are taken to address this issue, India could become "water scarce", when water availability drops below 1,000 m³ per capita per year.

Cities such as Delhi, Mumbai, Pune, Hyderabad and Chennai, as well as many small and medium towns, are staring at a scenario where their sources will completely run out of water. Bengaluru faced unprecedented water shortage last year. As India witnesses rapid urbanisation-most of it seemingly unplanned-the situation will get worse, especially with climate change manifesting itself as an intensification of the water cycle, resulting in frequent floods, droughts and water stress.

Reuse of wastewater is being seen as a new way of supplementing the water supply and mitigating the impending water shortage. Simply put, all used water is wastewater.

Its reuse will serve the twin purpose of augmenting water resources while reducing the environmental impacts of disposing untreated wastewater.