Treasure in excreta

Phosphorus, a fast depleting natural resource, can be extracted from the unlikeliest avenue: faecal sludge SHAGUN KAPIL NEW DELHI

- Shagun Kapil

HOW CLOSE is the world to “peak phosphorus”—that point in time when production of phosphorus will reach its maximum and it will get harder to access it? The answer to this question is crucial as its availability influences a country’s food security. Presence of phosphorus is essential in soil for crop growth and its shortfall can result in reduction of crop yield. But the reserves of phosphate rock, the main source of the element is fast depleting. With an annual increase of 2.3 per cent in its demand, phosphorus reserves will most likely get exhausted in another 50 to 100 years, states a 2015 study by professors of the West Bengal State University, Kolkata.

Phosphate rocks are concentrated in Morocco, Western Sahara, China, the US, Russia and West Asia. Therefore, most of the world, including India, has to import it. In 2018, Diammonium phosphate constituted 28 per cent of India’s fertiliser import.

Researchers point out that the world will reach “peak phosphorus” in 2030. By this time, India’s population is expected to reach 1.5 billion. How will we sustain food production with the shortage of such a crucial element?

An important phosphorus resource from where a huge reserve can be generated has been largely ignored. Human excreta is indiscriminately disposed into drains every day. “The solid matter that humans excrete is largely organic. It contains carbon, phosphorous and a whole lot of other nutrients. We consume these nutrients in the form of food. Leafy vegetables, for instance, have phosphorus,” says Vijay Athreye, founder of finish Society, a non-profit that works on waste and sanitation.