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Sunshine and saris equals safe drinking water


Researchers from Canada and India funded by IDRC have found that filtering water through sari-cloth before purifying it in the sun’s heat makes polluted water safe to drink. 

Polluted water is often the only source of drinking water for many low-income households in India. To kill the germs, people pour water into clear plastic bottles and then leave them out in the sun for several hours.

But debris in the water such as soil or bits of leaves can block the germs from the sun’s rays, making the treatment ineffective and the water unsafe. For this reason, cloudy water needs to be filtered before it is put into the sun.     

Researchers from the University of Guelph, the Indian Institute of Technology Madras, and Queen’s University tested dried seed powder (Moringa oleifera) and sari-cloth to see which one was a better filter for cloudy water. The researchers found that the most effective filtering method was to use the seed powder to combine materials in the water and then strain them out through the sari-cloth. Unfortunately, the team was concerned that the seed powder might encourage germs to grow again in the water. 

As a result, the researchers concluded that the best way to treat the water was to filter it through sari-cloth and then put it out into the sun.

Authors S.I. Ali, M. MacDonald, J. Jincy, K.A. Sampath, G. Vinothini, L. Philip, K. Hall, and K. Aronson explore improving water purification options in Chennai, India, in their paper, Efficacy of an appropriate point-of-use water treatment intervention for low-income communities in India utilizing Moringa oleifera, sari-cloth filtration and solar UV disinfection.

Their paper is a result of a project supported by IDRC’s Climate Change and Water program, Alternative Water Systems Project (India).