Is a UV filter necessary for water

Water treatment: a buying guide

How do you get clean water on the go when you are out outdoors, trekking or traveling long distances? Dr. Peter Schatzl, Center for Tropical, Travel and Geomedicine explains how you can produce drinking water yourself with water treatment tablets, UV radiation and outdoor water filters through correct water treatment.

Our demands on drinking water are manifold, even if they are not always met in all points. First and foremost, there is the requirement that drinking water should be free from contamination by pathogens. The spectrum of substances polluting water ranges from bacteria such as the well-known E. Coli, Cholera, Shigella, Salmonella to single and multicellular cells such as lamblia, amoeba, cryptosporidia and viruses such as rotavirus, adenovirus or hepatitis viruses.

What they all have in common is that in most cases they are absorbed through the mouth and manifest themselves in the digestive tract with symptoms of diarrhea. Other sources of contamination of drinking water include chemicals from industry and agriculture such as pesticides, nitrates or heavy metals, which are especially dangerous when consumed over a long period of time. This results in the requirement that drinking water should not cause any long-term damage.

Water treatment on outdoor trips & adventures

Last but not least, our drinking water should taste good, smell good and have a flawless appearance. Only then will we drink from it in sufficient quantities and without a guilty conscience. Often water is mixed with suspended matter such as algae, plant remains, animal remains, sand or clay. Although these are usually harmless, they can serve as a source of other impurities (e.g. bacterial colonies).

What goes without saying at home is the constant availability and harmlessness of drinking water from the tap. In most countries around the world this is not the case! We know this problem from long-distance trips, for example - especially in developing countries. It would be desirable to prepare the water to make drinking water from the source, the reservoir or in the pipeline system. Often, however, we are forced to treat drinking water at the point of extraction. If we have to store drinking water on site or transport it in tanks, it can be demanded that there is no change here due to storage. There are also special solutions for this, e.g. on ships or in caravans.

There are various methods of upgrading water of questionable quality to drinking water, whether during trekking in the field away from infrastructure or on long-distance trips. Four methods of outdoor water treatment are presented below.

Method 1: boil water

A very reliable method for the outdoor kitchen, as heat kills all pathogens. However, organisms are differently sensitive to heat. Some die earlier, others only die at temperatures above 100 ° C. Temperature and heating time are closely related. As a rule, it is sufficient to briefly boil the water (at 100 degrees Celsius); but if you want to be on the safe side, let it boil longer. It should also be noted that at high altitudes, water begins to boil at lower temperatures and therefore has to be boiled for much longer.

Boiling has no effect on the appearance, smell or taste of the water. The disadvantage of this method is the time and energy required (fuel consumption). The water has to cool down before you can drink it.

Method 2: water treatment tablets

Usually added to the water in drops or tablets, the halogen or iodine oxidizes all pathogens. Chlorination of drinking water, for example, is widespread in many cities in the Third World. The prerequisite is optically clear water (no suspended matter) and sufficient dosage of the halogen (if in doubt, better to use more than too little). The higher the dose, the more unpleasant its aftertaste becomes. This can be partly bound with activated carbon or improved with other additions. Additional factors when halogenating are water temperature, pH value and exposure time.

Micropur Forte from Katadyn disinfects clear water quickly and safely and keeps it germ-free for up to six months. The oxidizing effect of chlorine eliminates bacteria as well as viruses and most protozoa and fungi. Micropur Forte can be used wherever microbiologically unsafe water needs to be disinfected for drinking, cooking or washing. Use only in clear water. Cloudy water should first be filtered with a portable water filter.

Dose one Micropur Forte tablet to one liter of clear water; wait ten minutes for the tablet to dissolve; shake well; leave on for another 20 minutes before use.

Method 3: outdoor water filter

Microfilters hold back pathogens mechanically with their microscopic pores (pore size 0.2 to 0.4 micrometers). Most of the pathogens, especially bacteria, single and multi-cellular cells, do not fit through the pores and get stuck. The smallest pathogens, e.g. viruses, can still penetrate. Combined filters with activated carbon can also bind the smallest pathogens as well as flavor and odor substances.

Filters are particularly useful for smaller quantities and the water is quickly available. Depending on how dirty or cloudy the water is, the filter must then be cleaned or replaced. Points such as the weight of the filter, acquisition costs and ongoing maintenance are to be discussed here. We recommend water filters from MSR, SteriPEN or Katadyn.

Anyone who thinks that they are carrying half a processing system with a UV sterilizer is wrong. Our favorite for trekking tours and traveling is the compact oneSteriPEN water purifier for water treatment. It weighs just 100 grams including batteries. For one liter of water treatment with the SteriPEN you need about 90 seconds.

Method 4: UV irradiation of water

Highly effective UV-C light kills pathogens within a very short time. Previously only used on a large scale in processing plants, this method is now also available with handy battery-operated devices. Above all, turbidity of the water hinders this type of drinking water treatment (it is essential to remove suspended matter beforehand)! UV treatment also has no effect on the appearance, smell or taste of the water. Acquisition costs, weight and battery requirements must be compared here with the other methods.

You can find all products for water treatment for your next outdoor adventure here:

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