In The Storage, Filtration And Purification Of Water I covered water purification pretty thoroughly. Today I want to discuss the types of purification systems and their applications, as one purifier might be a better fit in certain situations.
Gravity Fed
These systems have one reservoir to hold unpurified water and often have a second reservoir to hold the purified water. These systems use gravity to pass the water through the filter at a slow and steady pace. In my opinion these systems are often best at home or at a base camp. They are often too big and bulky to be used in the field. The plus side of these units is that they are passive. The only thing you need to do is add unpurified water and take the purified water away.
Any of the pitcher type units such as PUR and other models are gravity fed. Some bigger names geared at preparedness are Berkey and MSR .
Pump
These systems force water through the filter. In most cases there is no reservoir, the dirty water can be taken directly from a source such as a river or lake. Or you can collect dirty water in a separate reservoir. You will also need to have a container ready to collect the clean water. To me, it makes sense to have a system like this in the field, along with your water bottle or canteen.
There are in house systems that attach directly to your faucet. These are pump fed. Some popular preparedness brands are Katadyn, MSR and Lifesaver.
Water Bottles with Purifiers
With these, you add water to the bottle and use a straw of sorts to suck the water through the filter. I think these are a solid second option, but the other options may be a better primary, with the exception of the Lifesaver. The Lifesaver is considered a pump, but it is the size of a water bottle and can filter water fast enough to be useful for multiple people, once the filter has expired on the lifesaver, a failsafe will not allow it to function until the filter is replaced.
Ultraviolet
Using an ultraviolet purifier will kill viruses and bacteria but will not remove any chemicals or other contaminants. To use this method you will need a container to hold the water and place the UV source directly into the water. The water in that container will then be free of bacteria and viruses. A downside to these is that they require outside power, either from batteries of electricity.
In my opinion this is a great option for backup purification.
Steripen and TrojanUV are two companies that produce this type of purification technology.
Chemical
Bleach, chlorine and Iodine water purification tablets are all methods that, like the ultraviolet, will kill bacteria and viruses, but won’t remove chemicals. In some cases such as with iodine will add a foul taste.
This, in my opinion, is another good backup method.
Final thoughts
In looking into the different brands and methods, I am very impressed with the Lifesaver. They do a lot of humanitarian work. It is their goal to end water poverty. They are trying to change the way people think about providing clean water in emergencies. Right now after a typhoon or hurricane, the thought is to bring in clean drinking water. Lifesaver is saying, “just treat the dirty water that is already there.” On their website they show a video of how the bottle works. The jerry can works the same way, though it can do more water at one time. I’m seriously considering buying one of the jerry cans. In the video the creator says that one jerry can will purify 25,000 liters.
If you’re interested in the Lifesaver products in the US, use this link to Lifesaver USA.
