Expedition kit – water purification

Prevention is better than the cure and, although drinking water from a burn is often safe, it is better to avoid the risk of illness in remote areas for the absence of doctors.

Viruses, pathogenic bacteria and protozoa increase water contamination risk and can cause upsets to the digestive system, which can in turn lead to illness. Even if water is clear and fast flowing one can never be sure what lurks upstream. Luckily there are plenty of ways to treat water when wild camping.

Boiling to purify water

Boiling water for a full minute is an efficient way to purify water and is reliable in killing bacteria, protozoa, parasites and viruses. Although water boils at a lower temperature at altitude it comes to the boil at a temperature exceeding 86ºC, the crucial temperature for killing all germs.

Adding tea leaves and pine needles are an additional line off defence against germs as they both have purifying qualities.

The disadvantages of this water purification process are as follows: boiling water requires fuel and time and leaves water tasting flat and lifeless diminishing its refreshing taste (water taste is defined by the oxygen and minerals contained within – boiling water reduces the oxygen content and therefore the taste). The freshness can be regained by vigourously pouring the water between containers to replenish the oxygen.

Filtering to purify water

One of the quickest methods of purifying water is to pump it through a water filter and this system usually eliminates bad tastes as well as bacteria, protozoans and parasites.

Many models are available but you can expect to purify a litre in about 5 minutes with no loss of taste. Some use ceramic and some use glass fibre filters and the latter will last longer before they need to be replaced. I always wash the filter with chlorinated water between trips to prolong its life and avoid clogging.

A major disadvantage to filters is that they do not guarantee the removal of viruses.

Using a Miox Purifier 

The Miox Purifier creates a purifying anti-oxidant by combining non-iodized salt with electricity from a battery. There is no need for pumping, nor is there risk that the system can clog as with a filter and there is no bitter after taste as with water purification tablets or water purification drops.

However, the gadget is reliant upon battery performance and, in the cold, batteries often have to be warmed in a pocket for half an hour in order that the system starts – and then, to kill some viruses the system can take some time – the most popular gripe with this system is the time it can take to kill some more resilient bacteria types. The Miox system does not filter water and does nothing to remove particles, which can be an issue for lowland murky waters.

Iodine water purification

Liquid or tablet purifiers are probably the quickest and easiest way to purify water, the only downside being the bad taste that results. Iodine removes all viruses, bacteria and protozoans (except Cryptosporidium cysts) and is available in liquid and crystal form.

Pregnant women, those taking lithium, those with a thyroid problem and those with an iodine allergy should avoid iodine use which should not be used for prolonged periods. Cloudy water should be filtered first as organic material can render the iodine ineffective. Water sanitised with iodine stays clean for three months.

The advantage with this form of water purification is that it is easy to carry and quick to use however it does not taste particularly pleasant. This unpleasant taste can be reduced if powdered ascorbic acid (vitamin C) is added to the water after the process. The vitamin limits the iodine’s effectiveness and should only be added after the time required for the iodine to take effect. It should be noted that the purifying process (killing Giardia cysts specifically) takes longer with cold waters.

Chlorine water purification

Chlorine is three times more effective at purifying water than iodine but the water does not stay purified for as long. It may take a similar time to take effect as does iodine and the chemical tasting water can be left to air to minimise chemical tastes.

Neither iodine or chlorine alone are considered completely effective against Cryptosporidium so a combination of filtering and chemical treatment is recommended for surety.

Octane tends to prefer boiling water in camp since we have both time and fuel. Spare water can be bottled for later use whilst paddling at sea. Once water is purified, by whatever means, try adding a fruit herbal tea bag to the bottle for five minutes before setting out. This will give a fruity berry flavour to the water for the rest of the day.

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