Simple filtration and low-temperature sterilization of drinking water

Waterborne infectious diseases are transmitted primarily through contamination of the water sources with excreta of humans and animals. The water treatment technologies available are fairly costly and not sustainable. Solar energy can be used effectively for sterilizing drinking water during clear and partially cloudy days. However, during mostly cloudy days the temperatures required may not be reached. A combination of traditional cotton-sari filtration and heating of water to simulate a solar boiler was evaluated as a water sterilization treatment. Experimental data showed that filtration of raw water through four-layered cotton-sari cloth (250 mu m) reduced the coliform count and further heating to sub-boiling temperatures (55-60 degrees C) for less than an hour resulted in complete inactivation of coliforms. The use of cloth filtration and low-temperature solar sterilization can be an effective, feasible and environmentally sustainable technique of disinfection to obtain clean drinking water.