Clean water is a necessity and in the backcountry or even at home sometimes, you have to take the proper steps to make sure what you drinking is safe.
In my first piece on the subject, I talked about purifying water using heat or chemicals. This time I want look at another way of doing it, and this involves filtering out the offending pathogens. As I said in my first story, safe water can become a concern even in the city, as in Monroe, MI. when a boil water alert was issued.
There are a large number of filters on the market, but they all essentially work the same. Suspect water is passed through a filter element which has pores small enough to remove the nastiest of the critters such as protozoa like Giardia or cryptosporidium; bacteria like salmonella and in one case even viruses. The question is just how small the pores need to be in order to remove the pathogens.
According to the Centers for Disease Control and Prevention in Atlanta, Ga., the absolute pore size must be 1 micron in size to remove Giardia and cryptosporidium and .3 micron to take out bacteria such as Campylobacter, Salmonella, Shigella and E. coli. All of these pathogens can cause illness that include diarrhea, vomiting and stomach cramps, and for those with weakened immune systems; the infections caused can lead to death.
There is another factor to keep in mind, there are water filters and water purifiers and they are not the same.
A filter will remove bacteria and protozoa, but it does nothing to viruses that could be in the water. Purifiers on the other hand, do what the name implies, purifies the water, either by killing the viruses with an added chemical stage in the filtering process, or in the case of the First Need water purifiers, it removes the viruses. Of course no matter what the device does, filter or purify, they must be certified to adhere to certain standards that guarantee they do the job.
For use in the backcountry in North America where the danger of viruses is considerably less than in third world nations, a water filter should do the job. There are quite a few on the market but the two filters I like are made by Cascade Designs and offer filter levels to remove everything but viruses.
Another fact to keep in mind is that water filters, such as the ones listed below are the only way to remove tapeworm cysts which can be found in some waters of the United States. One of these being Isle Royale National Park in Lake Superior. The only other treatment you can use when it comes to tapeworm cysts is boiling the water for two minutes.
The Platypus GravityWorks Filter uses gravity to pass the water through a filter element and then into a clean container. It uses a hollow core fiber technology, has a pore size of .2 microns and weighs only 10.75 ounces. The GravityWorks will filter 1.75 liters of water per minute, is field cleanable by back flushing and the filter cartridge life is rated at 1,500 liters before replacement. The kit includes the filter, all the fittings and hoses and two 4-liter reservoirs, one for dirty and the other for clean water. Retail price on this unit is $109.95.
Next is the MSR HyperFlow water filter. This is a standard pump type filter and it will process a lot of water in a short time. It uses the same hollow fiber technology as the GravityWorks and filtering down to .2 microns. It is rated at filtering 3-liters per minute and the filter life is said to be 1,000 liters. It weighs just 7.8-ounces and is field cleanable by back flushing. It comes with a pre-filter, bottle adapter, pump and tubing. It is easy to use, compact, light in weight and pumps one heck of a lot of water. Retail on this filter is $99.95.
Finally to the water purifier I have used for quite a few years and that is the First Need made by General Ecology Inc. I tested one of the First Need filters some years ago and when the upgraded version came out, I bought it. I will admit I go over the top about water purification and the fact that the First Need is certified to remove viruses has a certain appeal to me.
The First Need XL filters down to .1 micron and is made up of a “filter matrix” that somehow removes all the pathogens and along with them, viruses. There is a large carbon element to the matrix that will help remove certain chemicals and bad tastes in the water.
You can pump 2-liters per minute through the unit and the filter is rated at being able to purify just under 600-liters of water. But as long as flow continues through the filter, even if it is slow, water is being purified. The filter can be back flushed to extend the useful life and honestly, I have never had one stop working.
The First Need XL at 16-ounces is twice the weight of the HyperFlow and it is a bit bulky. But I have used mine to filter all sorts of water and it is absolutely a top rate filter. I have filtered water in ponds that had active beaver and other animals in it, that indeed do carry some viruses and I was not concerned using the First Need. The filter comes with a carry bag, pre-filter and gravity feed system that is perfect for in camp. Retail on the unit is $112.00.
Regardless of what filter you use, make sure you take a few extra steps before running the water through the filter. Get the cleanest water you can. In that beaver pond I mentioned, I filtered the water through a bandana first to remove as much sediment as I could. On Lake Superior, I let the very fine sand in the water settle out before using the filter. They are filters and can become clogged, so these extra steps will save you from a clogged filter and having to use chemicals or heat to purify your water