WildernessMag: 2021’s water filters and purifiers
2021’s water filters and purifiers
A water filter or purifier offers peace of mind and guaranteed safe drinking water at a hut, alpine tarn or stream.
How to filter
Always check – if possible – what’s in the water upstream to avoid contamination. Giardia slowly sinks, so draw your water where the flow is slow-moving, away from the bank. Avoid muddy water as it can contain bacteria stirred up from the streambed and will also clog filters.
The usual flow (or purification) rate is one to two litres per minute. It’s important to keep filters clean and free of sediment to ensure the flow rate remains high.
Water filters and purifiers are designed to protect users from water-borne illnesses like giardia, campylobacter, salmonella and E. coli.
To ensure the long life of your filter, clean it regularly. This is usually done by rinsing or backwashing and can be accomplished in the field as well as at home.
What purifiers do
Purifiers kill the much smaller viral and bacterial organisms. UV light is the most common and effective form of purification. It is important to follow instructions precisely to ensure the purification process is adequate.
The full system
Some systems use both a filter and purifier. The filter removes organisms down to 0.2 or 0.1 micron and the purifier deals with anything smaller. Unless the removal of organisms is at least 99.9%, there is a risk of infection.
When to use
If you’re carrying a filter or purifier, you should use it every time you collect water for drinking, even in the remote backcountry where the risk of contracting a water-borne illness might seem small. The risk increases in more popular areas, where people might go to the toilet near waterways or where animals are grazed. In urban environments, a disaster like an earthquake can make a water filter or purifier a life-saver. Because animals often fall into hut water tanks where they drown, it’s wise to filter or purify (or at least boil) any water you drink.
What filters do
Filters are the first line of defense against larger-than-a-virus protozoa and cryptosporidia such as Giardia Lamblia and parvum. Filters remove sediment and organisms down to 0.4-0.1 microns.
To continue to learn about water filter and purifier options for you, written by Alistair Hall, head here: https://www.wildernessmag.co.nz/2021s-water-filters-and-purifiers/