When hiking or trekking, the drinking water supply is a problem that should not be underestimated. Water must either be carried with you or treated on the way. You can read in detail here what options are available for water treatment on the go, and what advantages and disadvantages they have in detail.
Advantages of water treatment on the go
The supply of drinking water is often a weight problem for hikers and trekkers: For just a few days, at least two liters of drinking water are required per person per day. The water supply for a four-day tour is at least eight to ten liters - assuming you have little sweating. Even on a four-day tour, this means a weight of 8-10 kg that each person has to carry.
- Also read - biological water treatment - also for drinking water?
- Also read - Boiling tap water - for and against
- Also read - Chemical disinfection methods for drinking water
In most areas, however, there are plenty of water sources on the way where supplies can be replenished. As a rule, in Central European areas you hardly need to take more than the water supply for a day, often even less. The resulting enormous weight savings make trekking a lot easier.
So you don't have to be an ultralight trekker to rely on a water supply on the way.
Risks in the water
Any water, even from an apparently clear and clean source, can be heavily contaminated with germs. Even a single dead animal lying in the water can turn the course of a river into an extremely dangerous bacterial broth for a long distance downstream. Even in remote areas, pollutants can be discharged into the water or there may be residues of excrement, pesticides or fertilizers.
Since this risk can never be ruled out, all water is to be regarded as contaminated, and at least as microbially contaminated. Anything that is not tap water is not of guaranteed quality!
The most dangerous are:
- coliform germs from excrement in the water source
- Bacteria, pathogens and decomposition products of decaying carcasses in the water
- Chemicals, pesticides or herbicides, or other chemical pollutants
Basically, a distinction must be made between disinfection and filtration or ultrafiltration of the drinking water.
Pure disinfection may be sufficient to kill pathogens such as viruses or bacteria, but it does not remove harmful chemicals and not all protein substances that can be dangerous to the body. In addition, the result can never be checked, not all methods are one hundred percent reliable, even if UV disinfection with portable devices such as Steripen can be regarded as entirely reliable.
The method of choice is therefore always ultrafiltration. Portable water filters have filter pores in the size of 1 - 2 µm, and thus also filter out bacteria and germs. Additional disinfection is not required. If the water is very cloudy, pre-filtering with an activated carbon filter can be useful. Most devices for outdoor use have pre-filters of this type that are built in at the same time. Otherwise you can let the water sediment briefly in a pit to separate the coarser components.