Purify water with chlorine bleach

Last time we have learnt how to purify water with iodine tincture. But what if we can’t purify water through boiling, and we don’t have iodine tincture in hand, how can we purify water?

Let’s learn from the advice of US Military Field Manual FM 21-76 (FM 3-05.70) and learn how to use chlorine bleach to purify water.

FM 3-05.70 supersedes FM 21-76, and it was published in 2002.

How does chlorine bleach purify water?

We purify water in order to kill pathogens in it, avoiding infection of disease like Cholera. We use heat to achieve this result when we boil the water.

Chemical purification using chlorine breaks down the chemical bonds of molecule in water, thus killing most of the pathogens in it.

Since most bleaches contains chlorine, or more specifically, sodium hypochlorite, they can be used for water purification.

Similar to purifying water with iodine, chlorine cannot kill all parasites in the water, for instance cryptosporidium, a parasite that shows high resistance to chemicals.

Therefore, If you suspect there are parasites inside the water, you either have to filter it after purifying it with chlorine bleach, or find a new source of water.

Choose the right bleach for water purification

Only bleach contains chlorine, for example sodium hypochlorite, can be used to purify water. Check the label carefully beforehand.

Besides, you should avoid chlorine bleach with scent or dye(You can still use them if you don’t care the smell).

An empty bottle

A bottle of chlorine bleach

Purify water with chlorine bleach

This tutorial will teach how to purify water with chlorine bleach

Step 1: Preparation

Prepare an empty water bottle, and fill it up with water.

Step 2: Add drops of chlorine bleach into the bottle

According to US Military Field Manual FM 21-76, add 2 drops of 5.25% chlorine concentration chlorine bleach per liter of water. Add 10 drops per liter of water for 1% chlorine concentration chlorine bleach and 1 drop per liter of water for 7 to 10 % chlorine concentration chlorine bleach.

Step 3: Wait for chlorine bleach to purify the water

Give at least 30 minutes chlorine bleach to react and purify the water, then you are safe to drink it.

If the water is cloudy, wait 30 minutes more.

FAQs

How many chlorine bleach do I need to purify water?

According to US Military Field Manual FM 21-76, add 2 drops of 5.25% chlorine concentration chlorine bleach per liter of water. Add 10 drops per liter of water for 1% chlorine concentration chlorine bleach and 1 drop per liter of water for 7 to 10 % chlorine concentration chlorine bleach.

How long do I need to wait when I use chlorine bleach to purify water?

You have to wait at least 30 minutes after adding bleach into the water. If the water is cloudy, wait 30 minutes more.

It is possible to cover or remove the unpleasant taste of chlorine bleach in the water?

If the water has a strong chlorine taste, let the water sit while exposing to air for an hour or more to remove the smell. You can also remove it by pouring it back and forth between two containers, exposing it to air.

Can all bleaches purify water?

Only bleach contains chlorine, for example sodium hypochlorite, can be used to purify water.

What should I be aware of when purifying water with chlorine bleach?

Avoid using chlorine bleach with scent or dye.

Reference

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