If you want to know why it is essential to purify water when you do not know its quality, or if you ask yourself if you need a system of water purification for your hikes then read this new article, where you will be introduced to the advantages and disadvantages of the major processes of water purification and filtering.
Some of you may ask why collecting and purifying water when I can carry my own potable water from home. This is true when it comes to small distance hikes or day hikes but on the other hand for long treks or overnight hiking water becomes the heaviest item to carry and sometimes your daily needs in water is just too much to be carried.
In general you will need an extra liter of water for every 4 to 5 miles (6.5 to 8 km) of hiking. One liter of water weighs 1 kg so make the calculation.
This article will help you choose a water purifier system that corresponds best to your needs or realize that the one you use is not appropriate.
If you think that putting a Micropur tablet in a bottle of water allows you to drink any water, you are wrong.
If you think that filtering polluted water with the latest best hiking water filter will prevent you from being sick, you are wrong again.
It’s like when you are buying an antivirus for your computer, when we buy a water purification system, we easily have the impression to be protected against all contaminants – especially when it is an expensive one. The reality is quite different.
How to properly collect water and prepare it?
Whether you purify your water or not, you must collect and prepare it properly in order to limit the risks. Here are a few tips to do this:
- Collect water as clear as possible and the most upstream as possible of human activities.
- Collect water as far as possible of all polluting activities.
- Avoid stagnant water; micro-organisms develop there more easily.
- If the water is cloudy or contains particulate matter it is preferable to pre-filter it or to decant it to get rid of these particles.
Why and how to obtain clear water?
If you intend to purify water, it is essential that it be clear if you use a filter, a chemical purifier or a UV treatment. This will prevent clogging your filter or reducing the effectiveness of the UV chemical or treatment. If you do not intend to purify water, this is not essential, but it will avoid the taste of mud and the sand that crunches under your teeth.
The settling of the water consists of putting the water in a container and allows it to rest. This allows the particles in suspension in the water to fall to the bottom of the container. The smaller and lighter the particles, the longer the process will take.
If the particles are very small or very light, it is preferable to pre-filter the water. You can do this by passing the water through a coffee filter, a piece of cloth, a tee-shirt, or other.
Once your water is clear and ready to be purified, shake the container to oxygenate the water and get rid of a part of the anaerobic organisms.
The principle of this method is simple. You just need to boil the water for a period of time to kill the pathogenic organisms. It is certainly the first thing that most people think of to get rid of contaminants present in the water. The problem with this method is that it has a lot of drawbacks and a few benefits for hikers.
- Ideal to do the cooking.
- Eliminates most of the bacteria, viruses and micro-organisms.
- No additional hardware required (if you already have a stove) and fuel of course.
- Uses extra fuel.
- Long process – even longer in higher altitude.
- The purified water is hot. This is not ideal if you want to drink it and refresh yourself.
- Bad taste – after boiling water has a flat taste.
- Does not eliminate particles.
- Does not eliminate chemical pollutants.
How much time do we need to boil water?
The required boiling time is difficult to determine because it depends on the type of pathogenic organisms present in the water as well as the altitude at which you are.
At sea level, the water boils at 100°C. The majority of biological contaminants are killed in less than a minute to this temperature.
For the same result, it is necessary that the boiling lasts a few minutes when the water is at 85°C (boiling temperature of water at 4500 m or 14,700 ft of altitude) and approximately 30 minutes when the water is at 70°C (boiling temperature of water on the summit of Everest).
Backpacking water filters
The theory of a filter is simple: water passes through small size pores which retain the microorganisms and particles – exactly like a sieve to drain pasta.
Many different types of filters exist. Some are equipped with membrane, others with cartridges, some out of glass fiber, and others out of ceramic. The size of the pores varies – the smaller the pores the more effective the filter is.
Most current hiking water filters have pores with a size from 0.1 to 0.3 microns (micrometers) and retain everything that has a size greater than that. Some will go up to 15 nanometers (0.015 microns).
Some filters use only a mechanical filter, while others combine chemical treatments, active carbon, silver nanoparticles or other, for greater efficiency and versatility.
It is important for you to know what are the advantages and disadvantages of the backpacking water filters.
- Quick process – allows you to purify a large quantity of water quickly enough (depending on the type of filter). The smaller the pores, the lower the flow and the slower the process.
- Possibility to drink the water directly after the filtration.
- Eliminates particles and sediments.
- Some eliminate a part of the chemical contaminants – when the pores are quite small.
- Eliminates most of the bacteria and micro-organisms – this is the case of the conventional filters of 0.1 to 0.3 microns or smaller.
- High price.
- Maintenance – it is necessary to clean the filters, otherwise they become clogged and the biological contaminants can develop there. It is one of the things that the active carbon or the silver nanoparticles in some filters prevent.
- Weight – this varies depending on the filters but is generally higher than other means of purification.
- Most filters do not eliminate viruses (in any case the smaller one). This is the case of the conventional filters 0.1 to 0.3 microns. However, there are filters which allow eliminating almost 100% of the viruses, either through the very small pores, and either through an associated chemical treatment.
- It is necessary to pump for most of the filters, which can be tiring. It is a bit like using a bicycle pump. Some filters use gravity or suction and do not have this inconvenience.
- They can become dirty and clog up. The flow of water can then become very low or even stop.
- They can crack or get damaged due to frost, shocks or other. In this case they become ineffective or unusable.
Good to know:
Some bacteria are not eliminated by the filters of 0.2 microns or more. It is the case of the bacterium responsible for leptospirosis for example that has a size of 0.1 to 0.2 microns.
Some filters are filled with active carbon. The active carbon makes the water clearer, improves the smell and the taste, and above all absorbs a large quantity of chemicals such as chlorine, iodine, some heavy metals, pesticides, etc. which are therefore not present in the filtered water. On the other hand when it is associated with a filter, it decreases the flow of filtered water.
It may be difficult to filter water directly from a small river or a puddle of water by keeping the end piece in the water and avoiding the bottom, where are all the particles. In this case, it is convenient to have a container with which we can collect the water and decant it if necessary. We then filter the water from the container.
The chemical purifiers
The principle is the same as for any decontaminator. It consist of introducing a chemical product in the water and wait for a certain time to get rid of biological contaminants. There are a multitude of chemical purifiers. For hiking, the most common are the purification tablets.
- Light – with a few grams you can purify dozens of liters of water.
- Not bulky.
- Eliminates most of the bacteria and viruses.
- Some eliminate micro-organisms depending on the chemicals used.
- Bad taste – feels like drinking the water of a swimming pool.
- Expiry date – the purification tablets have an expiry date beyond which it is not advisable to use.
- Long process – the waiting time (contact time) goes from ½ hour to 2 hours depending on the brand and the degree of disinfection than you want. Even longer when the water is cold or cloudy.
- Must be used with clear water.
- You must respect the temperature of effectiveness.
- Some chemical purifiers do not eliminate all types of micro-organisms – some do not eliminate Giardia and Cryptosporidium for example.
- Do not remove particles.
- Do not remove chemical pollutants.
- Do not use too regularly – can damage the intestinal flora.
- Not recommended for people suffering from blood diseases or glandular disorders and for pregnant women.
The characteristics of all chemical purifiers are very different. Here are for example those of two very commonly used:
- Micropur Forte is effective after 30 min for bacteria and viruses, and 2 h for the majority of micro-organisms (including Giardia), and amoebae. It contains of silver ions, which allows you to keep the treated water for 60 days.
- Aquatabs is effective after 30 minutes for bacteria, viruses and some micro-organisms (Giardia for example but not Cryptosporidium). The water can be stored for 24h only.
- To eliminate “the taste of pool”, it is possible to add some fruit juice in powder or vitamin C in the treated water. Do this once the purification is completed because Vitamin C can neutralize the effect of iodine or chlorine.
- Given that it is necessary to wait for the chemical purifiers to be effective, I advise you to take at least two containers to alternate. In this way one of them will contain purified water and the other the water in the purification phase.
The UV (ultraviolet) water filters
This process uses UV rays which neutralize the organisms present in the water by preventing them from reproducing.
UV Purification Systems (portable UV lamp) have been recently developed and treat water through the emission of UV rays. They are generally similar to a pen, that is immersed in a container filled with water. Then you just have to activate it and to shake it for a few minutes to purify the water.
- Not bulky
- Effective – eliminates 99.9% of pathogenic organisms
- Fast – 1 to 2 minutes for 1 liter of water.
- Require batteries – which are not practical in hiking, especially for long hikes or treks
- Requires rather clear water
- High price
- Do not kill the organisms but prevents their reproduction. After an UV treatment, it is therefore necessary to avoid exposing the treated water to the light of the day during a prolonged period of time – which could allow some organisms to reactivate.
- Does not eliminate chemical pollutants.
Good to know:
Some people use the sun to do this. The water to be purified is contained in a plastic bottle (PET), which has been shaken to oxygenate the water and eliminate certain organisms. It is then placed in the sun for 6 to 24h depending on the solar radiation. Of course, this method is long, debatable and requires sunlight. But it is better than nothing and good to know in an emergency or survival situation.
How to choose your system of backpacking water purifier and filter?
The advantages and disadvantages of each system presented above should already give you a good idea of what system should be better for you.
Ask you first what types of contaminants you may encounter (viruses, chemical contaminants…) and choose from there. Your choice will mainly depend then on your practice and what you prefer – this may be the weight, the taste, the price, the versatility, the speed, etc.
Some people use combinations of system to improve the efficiency and better respond to their needs.
Combination of a water purification systems
Here are a few examples:
- Boiling + filter with activated carbon: boiling eliminates viruses, bacteria and micro-organisms. The carbon filter eliminates chemical contaminants and particles.
- Filter + chemical purifier (or UV treatment): the filter eliminates most of the bacteria and micro-organisms and larger viruses as well as particles. The purifier (or the UV treatment) eliminates the smaller size viruses once the water is clear.
When in most of your hikes it is possible to find drinking water at the bivouacs, you don’t need to purify all the water that you will consume. You can then use Micropur Forte “just in case” where and when there is not enough points of drinking water on your trek.
Get informed on all the potable water options during the preparation of your hike and properly collect your water are therefore two important points.
They are all the more important in desert regions like in Australia where the evaporation increases the concentration of chemical contaminants in certain waters.
A few additional tips to conclude
You should now know what system is best for you. There are other systems less frequently used as the oxidation, the distillation or reverse osmosis but I will not be introducing them here.
A few tips in no particular order to finish:
- This seems to really be a basic advice, but read the instructions and the characteristics of the purifier system. Each system is different, it is therefore imperative that you understand how it works, in what conditions as well as the types of contaminants that it allows to eliminate. Once you have read, observe them. Otherwise, it’s like drinking the water without purification.
- Pay attention to the neck and cap of the containers. Microorganisms may be hiding there. Clean them with purified water.
- It is always handy to have two containers minimum, either for decanting, pre-filtering or purifying the water.
- Have you thought about a backup solution if ever one of your systems of purification does not work? A filter can be clogged or cracked, a UV lamp no longer work, etc.
- Pay attention to your hygiene. Filter your water is necessary, but if you do not have a correct hygiene, there’s not much point in it. This would be like having very clean dishes but not wash your hands to eat.
And you, which system(s) of purification do you use when hiking? And for what reasons? Share this in the comments !