Alum stone to purify water

Water is scarce and expensive to obtain for much of the world. It may happen that rain occasionally falls and must then be saved on a large scale for later. The water set aside may be dirty, making it undrinkable. To clean the water, you can use the alum stone, so that unwanted substances will flake and descend into the water. How can the alum stone help make water clean and drinkable?

Alum stone for water purification

  • What is alum stone often used for?
  • Purify water
  • Method of application
  • Dirt will flake and descend
  • Reduced pH value
  • Boiling water


What is alum stone often used for?

The substance is used as standard for cleaning, disinfecting wounds, tanning leather and to prevent fungi or bacteria. It has an astringent effect on wounds, removing dirt from the wound and closing the skin. It therefore promotes the speed at which skin damage or wound repairs. Consider, for example, the use of alum for shaving wounds, but also as part of deodorants. Many of us use the substance practically every day without even knowing it. How can it be further used?

Purify water

In the Far East, the so-called alum stone is used to clean water that is not completely pure (also known in the Netherlands for its good effect against algae in ponds). Water is a scarce resource in many areas and must be used sparingly. It is collected via rainwater in large containers or barrels, where some unwanted dirt (limited dirt) may be mixed together with algae. How can alum help clean the water supply so that people can still drink it?

Method of application

If there is a large barrel of water, people would like to use it. If you drink it like this, it obviously has serious health consequences. What can one do? The alum stone can be purchased in hand size, which is used to stir water in the barrel. While stirring, small pieces of alum are released, which dissolve in the water. Depending on the amount of water, it is necessary to estimate how long it will take to run. A cubic meter of water will need to be stirred for approximately ten minutes before the effects mentioned above occur.

Dirt will flake and descend

The water may have a certain level of dirt but may also contain bacteria. Alum has the property of binding to proteins, whereby it has an aggravating effect on the contaminating elements. If you stir a barrel of water for a long time, flakes will eventually form in the water. These flakes also attract each other and become relatively heavy. It forms a concentration of all the dirt in the water. That is often the point at which the stirring of water is stopped. The particles will gradually sink as the water becomes quieter, after which all the junk will eventually settle at the bottom. In other words, there is clean water.

Reduced pH value

Bacteria can survive well in water, provided the pH value is favorable. If the pH value drops, the amount of bacteria decreases drastically. It means that these are purified from the water because the overall pH value drops slightly. It also descends to the bottom. Naturally, stirring with the stone must be limited so as not to obtain acidified undrinkable water. The combination of anti-bacterial effect with flaking or settling of dirt gives practically completely pure water.

Boiling water

Naturally, we Westerners have sensitive stomachs, so it is wise to additionally boil the top water from this barrel. It offers a final assurance regarding the complete elimination of all negative elements in the water. This method of water purification can provide a solution in many areas of the world when there is a shortage of clean drinking water. Naturally, the stone must also be available in that area, but in many parts of the world alum stones are quite cheap and available as standard. In this way, less pure water can be cleaned for further internal use.

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