There are many nomadic solutions to filter water for hydration and cooking (and incidentally to wash your teeth …). There is not a single, absolute solution but an answer to every need. The filter can be used alone or in combination with other elements such as chemical purification tablets or pre-filters.
Define your needs
Concentrate on these few questions and simply answer. These first elements will outline the style of equipment you really need.
What is the framework for using the filtration system?
We do not use the same filters when we are 100% nomads, camping, at home, by car, by bike … Some models are designed to be compact and lightweight while others have a design and features. performance adapted to a more stationary use. This is the case of the Katadyn Base Camp Pro model, which as its name suggests is recommended for base camp. Your choice will be influenced by the place in which you operate. In a country at risk, the filter will have to be more efficient and a chemical treatment will be essential. In the mountains you may find fewer hydrocarbons than in urban / peri-urban areas. In the countryside the waters can be soiled by dead animals or chemical treatments from agriculture …
The framework of use will condition these characteristics:
- volume and filtration capacity
- filtration performance
- combination of filtration systems
Who will use the filtration system?
If you are in a group, you will opt for a high volume gravity filter. If you are alone or two your choice will be different. A gourd / filtering straw can suffice for occasional emergency use, the Befree filter is a very good alternative. On the other hand it is hardly possible to share the same straw with his friends and you can then turn to a more suitable system like the Guardian MSR . The activity of the user can also influence the type of filter. An athlete, trail runner will prefer to opt for a lightweight, compact and quick to implement such as the MSR Trailshot. If you canoe, your boat will carry a larger filter …
The number of users will condition these characteristics:
- clutter and weight
- volume and filtration capacity
What should I watch out for?
When choosing a filtration system, pay attention to the following points:
- the type of filtration (chemical, mechanical …)
- technology (membrane, fiberglass, activated carbon …)
- performance in micron
- guarantees (against bacteria, viruses, protozoa, hydrocarbons …)
- filtration capacity (from a few liters to several hundreds of thousands)
The different filter technologies:
- Membrane: Microperforated part of the filter that lets the pressurized water pass. Some fiber diaphragms like Sawyer’s are self-cleaning and have an extremely long service life. Depending on the model, filtration removes most impurities (up to 99.999%)
- Fiberglass: Aside from viruses, this system captures most impurities including chemicals. Pumping is easier on this type of technology but it is impossible to clean them. The service life of fiberglass filters is lower than that of membrane filters. Katadyn uses this technology.
- Hollow fibers: Almost equivalent to fiberglass, hollow fibers do not retain chemicals and do not improve the taste of water.
- Activated carbon: it is a very basic technology that is only effective for filtering chemicals and improving the taste of water. an activated carbon filter is not suitable for filtration of protozoa, bacteria and viruses
- Ceramics: Even though it is ineffective on viruses, the ceramic filter is one of the most efficient on the market. It is suitable for all types of water, including very turbid waters. It is also easy to clean. His only problem is fragility. If the filter drops, the ceramic cartridge may break. It will no longer be possible to use it.
there are also UV treatment systems, ion exchange and of course chemical treatments (which are also virtually the only ones on the market to be effective against viruses).
Performance in micron:
The above technologies then make it possible to filter the pathogenic agents of different sizes according to their performance in micron:
- one of the most efficient filters, the Sawyer , offers a 0.1 μm fiber technology
- There are filters that can stop viruses by proposing a 0.02 μm filtration is the case of the MSR Guardian . It is one of the most complete filters on the market.
- Katadyn glass fiber filters are around 0.2 μm, this is also the case for some MSR filters such as the Trailshot
- Some filtering straws such as Lifestraw are also 0.2 μm
- Other models like the Aquamira Frontier Pro offer a 2μm filter and prove to be much less effective.
For information, here is the size of the pathogens:
- from 1μ to 15μ: Amoebic dysentery, giardia, lamblias, cryptosporidium, …
- from 0.2μ to 5μ: E-coli, salmonella, cholera, …
- from 0.02μ to 0.2μ: Hepatitis A, Norwalk virus, rotavirus, poliovirus, …
There is virtually no technology that offers complete filtration against viruses, bacteria, protozoa and chemicals (hydrocarbons etc.). However some models (ceramic or membrane for example) have very good results. The only advice to remember is the double purification: optimal mechanical filtration plus chemical filtration.
- With its self-cleaning technology, the Sawyer is the market leader when it comes to filtration capacity with no less than 375,000 liters.
- The MSR guardian offers a limit of 10,000 liters
- The MSR Trailshot 2000 liters
- The straw lifestraw only 1000 liters
- The Aquamira Frontier Pro will not exceed 100 liters.
- Some models combined offer to change a part of the filter to optimize the life, this is the case of Katadyn Combi which can change the activated carbon cartridge . He announces 50,000 liters on the ceramic cartridge and 400 liters on activated carbon.
In a second time, some factors, of the order of comfort, can guide your choices:
- Filtration speed (often technology dependent)
- the design (gravity, straw, mechanics …)
Attention, there is no quick fix and low prices. Do not play with your health especially when it comes to hydration and contamination, the risks are too high. Prefer the recognized brands like Katadyn, MSR, Lifestraw, Sawyer, Micropur … Refer to the many tests on the blogs of adventurers and outdoor enthusiasts.
An example of a water filter choice?
“We go for a two-day hike on a mountain GR, we carry all our equipment for a 15-day walk, and we have a daily supply of water for cooking, washing and especially hydration. “
Framework of use:
- during a mountain hike
- heavy use, several times a day
- use during bivouac
Frequency of use :
- long stays
- 2 persons
A possible solution of equipment adapted to this scenario:
When we go to two it is important to pool the equipment. The stove, the potty and the water filter, as well as the hygiene equipment and the sleeping system (tent / tarp) must be distributed according to the carrying capacity of hikers. There is no need to carry two stoves or two filters …
The environment in which our friends evolve is quite conducive to the capture of relatively healthy live water but pollution can spoil the exit: an animal dead upstream in the source or the torrent for example. Our hikers have very little chance to cross traces of hydrocarbon, unless hiking downstream of a high altitude station (in this case it will be necessary to think about using a charcoal filter like those in the Katadyn pump filter range. ).
If we summarize:
- the needs for filtered water are of the order of a few dozen liters per day
- there is no urgency, the filtration is to anticipate before the departure (so many liters for so many hours of walking) then filtration at the time of the bivouac.
- the sources of capture are numerous, clear and without hydrocarbons or chemical polluting agents
- the Guardian Purifier MSR proven. It is powerful and easy to use. It is relatively light and compact. It is compatible with Nalgene water bottles and most water bags . Its flow of 2.5 L per minute allows to quickly refuel the gourds.
- the filter straw Sawyer (Care Plus) is a very good response to our example. Even if it displays a reduced flow compared to the Guardian and a functioning less adapted to the “anticipated” filtration (recommended to filter if necessary), the weight and the congestion are the two big advantages of this system.
In addition to mechanical filtration it is strongly recommended to add a Micropur Forte tablet . With this combination you do not take any risk.
With each need its filtration system, all to find the right compromise. Having a good filter is not an end in itself, you have to learn how to use it properly. I propose on my blog Nopanic an article with a method step by step to purify water output .