Clean water

How to kill pathogenic bacteria, viruses, and protozoa in four easy steps

A class called Are We Doomed? Confronting the End of the World, taught virtually in Spring 2021 by astrophysicist Daniel Holz, SM’94, PhD’98, and sociologist James Evans, asked College students in the midst of “unprecedented times” to consider existential threats. Topics included nuclear war, climate change, disinformation, and—of course—pandemics.

For the final project, students were asked to create an object that might exist 30 years in the future. “Recipes for Disaster,” by Fatou Dioum, AB’23; Tim Granzow, SB’22; Shane Kim, AB’23; and Grace Wagner, AB’23, SB’23, is a “beginner’s survival guide to coping with the end of the world” and includes instructions for obtaining the most vital resource for life: clean water.

You will need

  • A clean cloth or coffee filter
  • Salt
  • Water
  • Containers with covers
  • A pot
  • Solar cooker or fire or stove

How to purify water

Step 1

If water is cloudy, let it settle. Then filter it through a clean cloth or coffee filter.

Step 2

Bring water to a rolling boil for at least one minute in a pot.

Step 3

To improve the flat taste, add a pinch of salt for each quart or liter of water.

Step 4

Let water cool naturally. Store in clean containers with covers.

Source: WHO, 2015.