Circular Economy: How Recovering Nutrients From Waste Could Ease India's Fertiliser Challenge

India spends a large amount of money importing fertilisers while at the same time flushing away billions of litres of sewage that contain the very nutrients those fertilisers provide. A circular economy approach asks whether this waste can be turned into a resource. The core idea is simple: human sewage and agricultural waste are rich in nutrients like nitrogen and phosphorus, and modern technology can recover these to make fertiliser instead of letting them pollute rivers and land.

The scale of unused waste is large. According to the Central Pollution Control Board, India generates nearly 73 billion litres of sewage a day, but treatment capacity exists for only about 44 per cent of it, and only roughly a third of total daily sewage is actually treated. The rest, carrying useful nutrients, flows away. India imported close to 15 billion dollars worth of fertilisers in 2025-26, so the same nutrients are being bought from abroad while being wasted at home.

Global experience shows recovery is practical. The Netherlands and Denmark apply more than half of their treated sewage sludge to farmland, and Germany has made phosphorus recovery from large wastewater plants mandatory by 2029. Estimates from the International Fertiliser Association suggest nutrient recovery from treated wastewater could meet up to 30 per cent of global phosphorus demand and 20 per cent of nitrogen demand, often at costs 20 to 30 per cent below synthetic equivalents. For India, recovering even a part of this could reduce import dependence and the foreign exchange spent on fertilisers.

Reaching this goal would require building far more sewage treatment plants, mechanising the handling of waste, and linking treatment to nutrient recovery rather than treating sewage only as something to dispose of. The Swachh Bharat Mission built about 100 million toilets between 2014 and 2019, but its focus was on building toilets rather than expanding sewage and septage treatment, leaving a gap between toilets and treatment infrastructure that a circular approach would need to close.

For an aspirant, this explainer connects environment and economy: the circular economy concept of turning waste into a resource, India's wastewater treatment gap, the link between sanitation infrastructure and self-reliance in fertilisers, and how nutrient recovery can lower both pollution and the import bill. Remember the meaning of circular economy, the role of phosphorus and nitrogen recovery, and the contrast with countries that already apply sludge to farmland.