How to Filter Water in Field Conditions
Access to clean water is not always guaranteed during a hike or in extreme situations. A source may be contaminated, there may be a dry spell, or the body of water could contain stagnant water. Sometimes, all that remains from all available water sources is a puddle. Remember the fairy tale: "Don't drink from the hoof, or you'll become a kid"? The same goes for water in extreme situations—not everything that looks like water is safe to drink. However, it is essential to replenish your hydration, and for that, the water must be purified.
Methods of Water Purification
In field conditions, you can choose the method that is most convenient for you:
- Boiling: The simplest and most effective method.
- Water Filters: Compact and large pump filters.
- Disinfection Tablets: Based on chlorine or iodine.
- Ultraviolet Cleaning (UV Sterilizers): An effective but less common method.
- Settling and Mechanical Filtration: An old method for basic filtration.
The steps for purifying water can be divided into two phases: removing mechanical impurities and disinfection.
First Step: Removing Mechanical Impurities
Before purifying the water, you need to collect it. Use a clean container and disinfect it if possible. It’s better to collect flowing water; if this isn’t possible, use a small cup. Choose a source with sandy bottoms to minimize mud intake. If the bottom is muddy, carefully scoop from the middle layers since harmful microbes are more prevalent in the upper layers.
The collected water must be cleaned of mechanical impurities—sand, mud, and leaves. You can use ready-made filters—pump filters or homemade filters.
A brief reminder about homemade water filters. In this water, eggs of worms and bacteria may remain in one way or another, and the levels of hardness salts and iron are exceeded. Such water must be boiled additionally, and disinfectants such as iodine solution (add 5 drops of a 5% alcohol solution to 1 liter of water), potassium permanganate (coloring the water to a faint pink hue), and hydroperite (0.5 tablets per 1 liter of water) can be used.
Modern filters can remove impurities and microorganisms from the water. Depending on the type of filter, they may only filter out mud or also eliminate viruses and bacteria. For complete purification, models with a pore size of 0.02 microns should be chosen. Most models are also equipped with activated carbon filters that remove unpleasant odors as well as pesticides.
Before selecting a filter, familiarize yourself with how it works: some purify water immediately (pump filters) but require manual pumping; others take more time (mechanical filters), allowing you to rest while they work. Bottle filters have limited volume capacity. An effective filter has two purification stages: a pre-filter for mechanical impurities and a main filter for viruses and bacteria. However, such filters are hard to find and cost around €150.
Therefore, it is important to disinfect the water after purification.
Second Step: Disinfection
Visually clean water does not automatically mean it is safe to drink—especially from questionable sources. Drinking such water can lead to severe illnesses; therefore, the water should be disinfected before consumption.
Boiling: This is the simplest method. When boiling, small residues settle at the bottom, and harmful microbes die due to high temperatures. At altitudes up to 2000 meters, water should be boiled for at least five minutes; above 2000 meters, ten minutes are required.
Ultraviolet: UV cleaning kills many microbes but not all of them. This method should only be used when no other options are available. Portable UV water purifiers are available; these need to be submerged in water for the specified time.
Chemical Disinfection: Tablets or powders that kill harmful microorganisms are added to purified water. The dosage is provided by manufacturers; such products are available at pharmacies. An example includes tablets found in military pharmacies; they kill many harmful bacteria. Additionally, iodine and potassium permanganate can be used; however, attention must be paid to dosing.
Conclusion
Water is crucial for an active life. Its quality directly affects your well-being and health. Therefore, be cautious about what you drink; use filters, boil your water, and pay attention to your health.