A water filter like MSR's Miniworks EX squeezes dirty water through a special filtration system. The water is cleaned of dangerous germs and is then drinkable.
For the success of trekking tours (such as on our Morocco tours) it is quite crucial that you can walk with full physical health. In 2010/11 it would have even become life-threatening without clean drinking water, as this tour was partly trail-less and one to two days marches outside any civilization. In addition, we needed good planning and luck to find surface water at least once a day. Most of the time this was a puddle, light green from algae with a slightly musty smell.
As I travel back to Morocco at the end of January and do a trekking tour through the Djebel Sarhro, I submit the test report here MSR Miniworks EX water filter in front.
Dangers due to polluted water
The dangers of polluted water are well known, so I'll just briefly remind you of the main sources of danger: parasites, protozoans, bacteria and viruses, as well as chemical contaminants. In the article to Water treatment outdoors I go into more detail on the dangers and the possibilities of avoidance.
Design principle of the filter
The MSR Miniworks EX water filter is very simple and can therefore be disassembled and cleaned without tools. The main components are the hand pump, which builds pressure in the cylinder by stroke-and-pull movement. In this cylinder is the ceramic activated carbon filter, through which the contaminated water is pressed. The ceramic insert has extremely small pores (0.0002mm), where bacteria, viruses and protozoa get stuck. The water is then purified by the activated carbon filter of (some) chemicals and unpleasant off-tastes.
But beware: everything that fits through the pores, which is smaller than the 0.0002mm, lands naturally in the drinking water. So some viruses are much smaller - and can only by additional decoction or chemical disinfection be killed. For risky water sources, a combination of the methods filtration and chemical water sterilization is recommended.
When handling, care should be taken so that contaminated water can not immediately contaminate the newly filtered water. Also, the filter candle should be cleaned regularly and boiled at home after the tour to rid it of adhering germs.
Especially small and light is one pump filter like the MSR Miniworks of course not, but the benefits outweigh the disadvantage by far. Especially in high-risk areas, where one has to rely on open water for drinking water supply and can not rely on bottled and sealed (mineral) water, a well-functioning water purification system is important. Here, a combination of mechanical filtration and possibly subsequent chemical sterilization has proven itself.