Drink water, but not just any water
Drinking water directly from a stream, lake or torrent is very dangerous. Contrary to popular belief, clear water is only rarely synonymous with pure water or drinking water; it often conceals many pathogenic microorganisms such as bacteria, viruses, protozoa and amoebae. By using a water filter,you can refrain from transporting important water reserves,hiking ortrekking, access to drinking water becoming possible anywhere.
How filters work
The filters work on a system similar to that of a colander. All suspended particles and microorganisms remain blocked by extremely fine meshes. Two technologies exist in mechanical filtration: ceramic filter systems or fiberglass filtersystems.
Ceramic filters consist of 0.2 μm micropores. Fiberglass filters consist of a membrane whose mesh has a maximum diameter of 0.3 μm. In both cases, harmful and protozoan bacteria, such as amoebae or giardia, are trapped mechanically. In addition to this basic essential filtration,some filters also contain an activated carbon cartridge.
Contrary to popular belief, activated carbon alone cannot filter pathogens. On the other hand, it reduces the level of chemical pollutants and/or heavy metals and thus improves the taste and smell of water. There are two main categories of carbon filters: pump filters that offer a good efficiency of 1l to 4l per minute, and gravity filters simple to implement but which have a very slow flow rate, from 4l to 5l per hour, more suitable for a base camp.
Characteristics of different filtration technologies
- Ceramic filter
This type of product, durable, has a cartridge that can be cleaned and can be replaced. Its service life can be up to 50,000 liters. Of not very fast flow,because with the tight mesh,it produces from 0.5 liters to 1 liter per minute in general. It allows to filter all the waters, even the muddy waters,except in the case of mini cartridges.
- Fiberglass filter
This type of product has a wider mesh and therefore allows to obtain a higher flow rate, reaching 2 liters per minute. Its service life is shorter than that of the ceramic filter, does not clean and must be replaced when it clogs. Economical and light, this type of filter is recommended for fairly clear and non-muddy waters, which could clog it too quickly.
Choosing a product adapted to your needs
- Bottles with integrated filter
You can find on the market bottles with integrated filter: a pre-filter made of fiberglass eliminates bacteria, protozoa, and microorganisms larger than 0.3 μm; it is supplemented with an activated carbon filter,which reduces the risk of chemical pollutants. They work by pressure and suction,and make it possible to obtain pure water everywhere on the move, in small quantities. These gourds allow to filter about 100 liters,and are relatively light,about 250 grams.
Average price: 50€ and for top-ups: 40€.
- Pump filters
There are also pump filters,with ceramic filter elements of 0.2μm,equipped with a water pressure relief valve in case of obstruction, which protects the filter and prevents it from breaking. The water outlet can be screwed onto bladders directly. They offer a range of 2000 litersfor an average weight of 500 grams.
Average price: 90€ and for top-ups: 45€.
In the different models, we can also distinguish according to the uses:
– small ultra-light pumps and pocket size can also be an asset. They weigh an average of 200 grams and can filter by an average of 7,000 litres.
– endurance pumps, with a long service life,which can filter up to 50,000 liters with a cartridge and ultra resistant, for long and professional uses. They weigh an average of 500 grams and are usually guaranteed for a long time, up to 20 years.
Average price: 300 € and 190 € for the cartridge.
– tap pumps, which are grafted onto a faucet for domestic use,useful for filtering muddy and turpid water. They can filter up to 50,000 liters for an average weight of 750 grams.
Average price: 220 €, cartridge at 100 €.
- Another product: gravitation filters
These simple filters work by gravitation; attached to a tank, they filter the water that flows through them and which is then sent to a lower container. This is an interesting solution for base camps. There are some with a built-in bladder of 10 liters or more, which rolls when moved.
Price: from 70€ to 120€.
Chemical purification of of water
This method is recommended for short stays or in addition to a filter,depending on the state of the water. Practical, inexpensive,it comes in the form ofa single-use tablet for individual use or in liquid form to treat large quantities of water. Two large families are used: the silver ion family,which keeps clear water particularly well for 6 months, and the family of chlorinated derivatives,very effective against bacteria and protozoa. Current products generally combine the two compounds.
To use these tablets, check the stability at temperatures or tropical conditions according to the type of trip envisaged. Follow the dosage, usually 1 tablet per 1 liter of water. Let the tablet dissolve for at least 30 minutes,in clear, filtered water if it has suspended sediment. The water thus obtained is stored for an average of 72 hours.
Katadyn is an excellent Swiss brand for this kind of products.