Repsol YPF

Immediate access to drinking water is a luxury of developed societies which is so easy to get accustomed that we undervalue its importance. According to the WHO more than 1,200 million people lack an adequate water supply, and no less than 80% of illnesses are related in one way or another to water. Its consumption, if not correctly treated, can cause typhoid, gastroenteritis, and cholera, among many other illnesses.

However, in addition to this serious situation, there are other contexts closer to home where we can appreciate the value of drinkable water. Any excursion where we practice hiking, mountaineering or simply staying in sparsely inhabited areas with little infrastructure for a few days requires a supply of drinking water, which is difficult to obtain and transport. To solve this problem, at least in the short-term, there are two simple and direct methods.

The first is to use chemical products, in the form of purification tablets or disinfectant liquids. It is necessary to know beforehand with what kind of water and in what areas they can be used, and there are a wide range of prices. However, they generally share the characteristic that they require at least two hours before the water can be drunk, which will have an unpleasant taste.

The other system is to use purifying filters. They are equally easy to transport, but have the advantage that they allow for a more prolonged use, almost immediate consumption of the water, and furthermore, this does not taste of chlorine, bleach or iodine (or it is less intense). However, although many of them are effective in the elimination of impurities, protozoa and bacteria, only some of these products also filter the viruses which may be present in the water. As such, it is worth obtaining good quality information to find out if they are suitable to use in terms of the country you are in and the type of water you have access to.

Different models

One of the most portable and successful purifiers is the LifeStraw. It consists of a small blue tube which allows you to drink directly from the place where the water is located as if you were using a straw. Their iodine filters eliminate viruses and bacteria, as well as 99.99 percent of waterborne parasites. This product is sold at a token price in African countries (around sixty euro cents), given that most of its cost is subsidised by the UN and by a number of NGOs. 250,000 units of this product have been distributed in the neediest countries, and in richer countries (where its price is higher, although very accessible) it is also a good choice for hikers and mountaineering enthusiasts.

The LifeSaver Bottle is a product with very different characteristics and a price of over 150 euros. It comprises, as its name suggests, a bottle, which is equipped with a pump. The water to be purified is placed in the bottle and instead of using chemical products it consists of very fine filters—so fine claim its manufactures that they do not permit the passage of viruses (the filter size is of 15 nanometres, while most viruses are 25 nanometres in size).

The SteriPen is shaped like a thick felt-tip pen and its manufacturer assures that it destroys bacteria and viruses. It does so by means of ultraviolet light produced by four batteries in its interior. (Although it sounds like science fiction, the use of this light is a common method of disinfection in laboratories and on food-packaging lines.) Its cost varies around 110 euros, depending on the model.

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