Friday 31 October 2008

Andy's guide to water purification

When travelling overseas clean safe drinking water is always a problem. One solution is to buy bottled water, but on average it will cost you $1 a litre and this can add up. There is also the environmental cost in buying plastic bottles that are rarely recycled in less developed countries that lack the infrastructure. So what are the options?

1. Iodine
This is the cheapest and most effective option and is available at camping stores and on the web in tablet or liquid form. It kills all known parasites including giardia. Simply add the correct amount, shake and leave for 15-30mins depending on the product. The downside is the taste, however you can also buy neutralisation tablets. Long term exposure to iodine is also not recommended. Prices from £3.99 75 - 200litres

2. Chlorine
As readily available as iodine, but not effective against giardia. However, it is slightly more palatable, tastes a little like swimming pool. Prices from £3.99 - 70litres (neutraliser @ £3)

3. Filters
These come in all shapes and sizes from pocket to backpack size. Simply its a pump and filter, so a bit of effort on your part is needed. They also need regualar cleaning and replacement filters fitting depending on how much you use it. They are expensive around £80 and fairly bulky. However on the plus side they can purify 1000's of litres of water.

One neat solution is a filter inside your water bottle. They cost around £40 and will purify 350litres of water.

4. SteriPEN
These have been on the market for a few years now but are not well known. They use UV light to kill bugs and can purify a litre of water in just 1.5minutes. They are also pocket sized but do require a fair bit of battery power. However combined with a solar charger it's a winning combination. Expect to pay £70-85 depending on the model, 4 x AA batteries = 20 - 30litres water.

5. Boil
Yes the cheapest option is to simply boil your water. The argument on how long this needs to be done for is sure to go on for years to come. Most guides will tell you to bring to a rolling boil for 3minutes, however new evidence suggests that it just needs to reach a rolling boil to be safe to drink. I would always air on the side of caution and boil mine for 3 minutes or more. A clean sarong can be used to filter larger particals.

So what's right for you? Think about how long you will be away. If you are only going for a short period go for iodine, you will soon get used to the taste. If you are set on travelling for a long period or multiple trips it might be worth investing in a filter or steriPEN.


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