Water Treatment

Last year, the Indian conglomerate Tata launched the Nano, a revolutionary low-cost car aimed at people who previously could afford only small motorcycles and scooters. Earlier this month, the firm unveiled the Swach, an innovative household water filter requiring no electricity and retailing for as little as $21.

“The social cost of water contamination is already enormous and increases every year,” said Ratan N. Tata, chairman of Tata Sons, at the launch event. “Today’s announcement is about giving millions more people affordable access to safe water.”

The Swach will be produced by Tata Chemicals in Haldia, West Bengal, one of India’s poorest states. A spokeswoman tells C&EN that although the microbial purifier is not designed to remove heavy metals and agrochemicals from water, it is effective against waterborne viruses and bacteria that cause diseases such as diarrhea, jaundice, typhoid, cholera, polio, and gastroenteritis.

The Tata group of companies says it spent several years developing the Swach. One of the product’s key features is a filter cartridge that stops water flow when it needs to be replaced.

The filter at the heart of Tata’s Swach is made of rice husk ash impregnated with nanosilver particles. In recent months, concerns have been raised about the leaching of nanosilver particles from clothing during washing (C&EN, Nov. 30, page 25), but the firm says the Swach has been “rigorously tested to meet internationally accepted water purification standards.”