The outbreak of a severe gastrointestinal infection among numerous hikers at three mountain lodges in the Allgäu Alps kept the region’s mountain rescue and emergency services busy over the past two days. Thus, the guests complained of severe gastrointestinal complaints with massive vomiting diarrhea and in some cases even had to be picked up by rescue helicopters. A total of almost 20 people have been affected so far. The cause of the infection is unclear; it could be a norovirus infection, but infections with coliform germs, Escherichia coli or enterococci through source water contaminated with excrement are also conceivable. In 2009, there was a major outbreak – also in the Oberallgäu region – in which around 230 lodge guests and hikers fell ill with gastrointestinal infections; 40 had to be treated in hospitals at the time.

In the Alps, there are just under 575 lodges run by the Alpine Clubs of Germany, Austria and South Tyrol, including 325 managed DAV mountain lodges with around 24,000 guest room places. Mountain lodges are usually not connected to a central drinking water system, but have to treat their drinking water from spring water decentrally themselves. Especially in public mountain lodges, the safety of the drinking water is of central importance; damage to the health of visitors and residents must be reliably excluded. But springs in the mountains are mostly surface-affected and carry turbidity and pathogens depending on the weather and season (heavy rain, snowmelt). In addition, there is often grazing in the area and so traces of dung from cattle, goats, etc. can get into the water. If the water is temporarily stored in catchment tanks for a longer period of time, further impurities can be introduced. Spring water is therefore not microbiologically safe and must be treated.

In mountain lodges, many people usually stay in a confined space and are reliant on the safe drinking water treatment of the mountain hut to refill their reserves.  Hygiene deficiencies or contaminated drinking water must therefore be avoided. Thus, proper drinking water treatment is particularly important in mountain lodges. Conventional treatment techniques, such as multi-layer filters or UV irradiation, only work reliably if pathogens are not surrounded by turbidity. In practice, however, these requirements are often ignored, and disinfection of drinking water by UV irradiation is carried out without sufficient turbidity removal. Only ultrafiltration ensures complete removal of all turbidity and pathogens such as bacteria, viruses, parasites, and thus safe operation of a downstream UV system.

An ultrafiltration system consumes only approx. 5-35 watts, can also be operated with photovoltaics (12 V) and is thus able to guarantee safe drinking water treatment even in the event of a power failure. Dissolved components in the water can be removed by a downstream activated carbon filter.

The Gufferthütte (Austria) has been working for over 10 years with a double barrier of Seccua ultrafiltration in combination with UV irradiation against any pathogens and can offer “hygienically perfect drinking water” even when the lodge is fully booked. If a high number of fecal indicator germs is regularly measured in the raw water, no germs are detectable after ultrafiltration. In many mountain huts in the Allgäu and Ammergau Alps, in the Karwendel and Rofan mountains, but also in the Sierra Nevada in California, Seccua filtration systems have been ensuring germ- and turbidity-free drinking water for years.