Chlorination.
https://www.emergency-wash.org/water/en/technologies/technology/chlorination
👉🏼 PDF: https://app.box.com/s/tiekdscffj2rp2yvbmvqlevfvlxfxalg
Chlorination is a final drinking water treatment step, as it inactivates pathogens such as bacteria and viruses. It is also used for other purposes such as disinfecting infrastructure (e.g. wells, pipes or boreholes) and equipment (e.g. in cholera treatment centres, X.14). It is used in all phases of an emergency.