Water purification methods for trekking

There are three methods to purify water.

Boiling

Boiling effectively kills all the harmful things listed in my previous post, so its great! However, two things to note.

• Water boils at different temperatures at different altitudes so I’m not really sure if it effective in higher altitudes (will go and find out more!)
• Boiling is quite cumbersome. You have to set up your stove, get the water, and you need to wait for the water to boil, which takes time. Moreover, the water will not be immediately drinkable because it will be hot!

Chemical Treatment

There are a couple of ways to chemically treat the water to make it drinkable.

• Chlorine tablets - You can ask for “Water purification tablets” or “Aquatabs” from Guardian Pharmacy in Singapore. Each box of 50 tablets cost about $5.00, which makes it $0.10 per tablet. To use the tablet, fill a 1 litre bottle with water (I typically use 1.5 litres - they are fine too), and then put one tablet and let it stand for 30 minutes. After that, the water is ready for drinking. If you are worried, use only 1 litre. I’ve tried one tablet to 500ml. If you like swimming pool water, you will like the solution
• Iodine - Iodine comes in tablets or crystals. Iodine, however, has a taste, so it is recommended that you mix the water with favored drinks. I have not used it personally before, so I am not too sure about the ratio and stuff (again, more to find out!)
• Potassium Permanganate - Comes in crystals. Recommended for emergency use only, because the solution is not good for you in the long run! When you add too much of it, the solution becomes a disinfectant that can be used to clean wounds… so imagine drinking disinfectants. :/ This, however, is a good option if you can’t boil it or use any other purification method. The ratio is one or two crystals with about 1 litre of water so the water turns very light pink.

Filtering

Filtering basically strains out the suspended solids in the water. There are two types, gravity fed or pump fed. There are also two different ways in which the water is filtered.

• Membrane filters - thin sheets perforated with precisely sized holes, just like your coffee bag, only more precise.
• Depth filters - thick porous material to trap particles like compressed carbon. I used to use this when I was in Australia, when I was really really lazy to boil the water. I had a gravity fed carbon filter. Note that these filters will eventually clog and so you need to change them.

Tags: trekking food