Every gallon of purified drinking water is home to hundreds of millions of bacteria. Water treatment facilities try to remove them – but perhaps encouraging some of the microbes to grow could benefit human health. Lutgarde Raskin of the University of Michigan in Ann Arbor says that workers at water treatment facilities across the US try to destroy all of the bacteria in drinking water with infusions of chlorine and other disinfectants. But this is nearly impossible to achieve with the current technology.
