HIking in the backcountry often requires adequate water filtration.
Long-distance backcountry hikers need to resupply their water stores daily while on the trail. Most trails do not offer potable water caches--instead, the hiker must draw water from natural sources (e.g., ponds and streams). To avoid the risk of sickness, many hikers use a water filter.
How Filters Work
A hiking micro filter works by taking water from a questionable source and passing it through several layers of filtration. The first layer is typically a sediment barrier, and then a replaceable disk made of charcoal and ceramic. The ceramic has small holes in it to reduce the size of the contaminants that flow through it, and the charcoal helps remove chemical impurities. Depending on their size, filters can last for 75 to 800 gallons of purification.
Risks from Untreated Water
Untreated water may contain pollutants that cause significant distress to a human's gastrointestinal system. Giardia, cryptosporidium and other biological contaminants (bacteria, viruses and protozoa) can cause several days' of digestive problems including diarrhea and nausea, which can lead to dehydration.
Although most filters are 99.999 percent effective at removing biological contaminants, filters provide limited protection against turbid water and have varying degrees of effectiveness at removing chemical contaminants--usually through the a charcoal filtration layer.
Filter Types
A pump filter works by drawing water in through an intake port and forcing it through the filters to a clean-water hose on the other end; the water moves because it is pumped with a handle. A gravity-fed filter works differently--it feeds a filter at the bottom of a large water sac, and the weight of the water provides the force that keeps fluid moving through the filter. There are also straw-style hiking micro water filters that screw into a standard water jug, and the water is filtered as it gets sucked up the straw into the thirsty hiker's mouth.
Purification Without Filters
In addition to filters, there are a variety of other options for backcountry water purification, including chemical treatments (often using iodine, chlorine or activated oxygen) and a ultraviolet pen-light that sterilizes small quantities of water in less than a minute. In addition, allowing water to reach a rolling boil will kill biological contaminants, although many backcountry hikers choose not to invest the time in boiling.
Weight
Many long-distance backcountry hikers practice "ultralight" gear selection--that is, they find the lightest possible piece of equipment that will serve their needs. For that reason, many ultralight devotees will not use a traditional filter and instead rely on chemical purification, such as Aqua Mira tablets or a few drops of chlorine bleach, saving themselves a half-pound or more in total pack weight. Consider the weight of any filtration system before using it on a long-distance hike.
Tags: backcountry hikers, biological contaminants, filter works, hiking micro, through charcoal, water from
