In a unique study carried out in drinking water pipes in Sweden, researchers from Lund University and the local water company tested what would happen if chlorine was omitted from drinking water. The result? An increase in bacteria, of course, but after a while something surprising happened: a harmless predatory bacteria grew in numbers and ate most of the other bacteria. The study suggests that chlorine is not always needed if the filtration is efficient—and that predatory bacteria could perhaps be used to purify water in the future.
