A Drop to Drink

Each year, water-borne diseases kill an estimated three million people and sicken more than two billion more. One method of decontaminating disease-fouled water uses solar rays, but it works only in parts of the world that get plenty of sunlight. Now an MIT doctoral candidate has found an efficient way to determine whether solar disinfection will work in a given area.

For his master's project in civil and environmental engineering, which he described in the January issue of Water Research, Peter Oates, Mng '01, developed a mathematical model that suggests that in Haiti, solar disinfection can be used year-round. He "went to the NASA data that averages the amount of solar radiation on the planet and came up with a simple model to predict whether it is worth looking into solar disinfection in a certain region," says Oates's advisor, Professor Martin Polz. Solar disinfection relies solely on the heat and ultraviolet radiation of the sun to make water stored in transparent containers drinkable.

Oates says MIT students have used his model to evaluate solar disinfection for other regions, including Nepal. But he favors prudence when using it. "Because we're dealing with human health, I would err on the cautious side," he says.