Year 2023 face_with_colon_three
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.
Just as human intestines contain a rich bacterial flora, many types of bacteria thrive in our drinking water and the pipes that transport them. On the inside of pipe walls is a thin, slippery coating, called a biofilm, which protects and supports bacteria. These bacteria have adapted to life in the presence of chlorine, which otherwise has the primary task to kill bacteria, particularity bacteria that can make humans sick.
An ordinary glass of drinking water contains a lot of harmless bacteria. Chlorine, however, which in the studied piping system was added in the form of monochloramine, is not wholly unproblematic.