Purification vs. Filtration — Filtering Fact From Fiction

by Alex Sepulveda

The difference between water purification versus filtration is that purification eliminates viruses, whereas filtration does not. Most purifying systems use a chemical component to destroy viruses in addition to regular filtration.

Goals

Filtration and purification seek to remove chemical contaminants and disease-causing organisms from your drinking water. The most common pathogens fall into three major groups: protozoa, bacteria and viruses.

Filters and purifiers remove chemical contaminants using carbon in a process called adsorption whereby contaminants bond to the carbon and are sucked out of the water.

Protozoa, bacteria & viruses
Generally, the greatest concern is killing those nasty little critters that live in water and wreak havoc on the human body. Protozoa, such as Giardia and Cryptosporidium, are the number one threat; followed by viruses like hepatitis A; and finally bacteria like E. Coli.

Giardia lamblia

Filters remove the larger microorganisms, protozoa and bacteria, but no filter is small enough to remove viruses. “[It’s] impossible to filter anything less than 0.2 microns*,” says Eric Miller, Sales Representative to MSR (Mountain Safety Research), “so viruses must be killed with chemicals.”

Purifiers use a chemical disinfectant—iodine being the classic example—to eliminate viruses. To be called a purifier, a treatment must be registered with the U.S. Environmental Protection Agency (EPA) and meet stringent standards.

Who needs purification?
Anywhere you’re recreating in areas that see heavy human traffic—popular trails or campsites—there is the chance that viruses lurk. Purifiers are ideal in these situations.

While viruses are generally not as big a concern in the U.S. backcountry, protozoa like Giardia and Crypto are pervasive, albeit to different degrees. Filtration eliminates these protozoa efficiently.

If you’re traveling to developing countries where waterborne viruses are more common, a purifier is a wise choice; the most popular being the First Need Deluxe.

First Need Deluxe Water Purifier

Traditional chemical treatments like iodine often impart a foul flavor to the water, and can take up to 45 minutes to work. Aqua Mira is an excellent alternative, and though not officially classified as a purifier by the EPA, it will eliminate the majority of waterborne pathogens. Used in conjunction with a water filter such as the MSR MiniWorks, this is a very effective purification system.

An interesting alternative to chemical purification comes in the EPA approved Hydro Photon Steri-Pen. Look for other cutting-edge alternatives from MSR this fall.

Hydro Photo Steri-Pen

* A micron equals 1/1000 of a meter. The smallest item visible to the naked human eye is 25 to 30 microns. Protozoa are as small as 2 microns, bacteria 0.25 and viruses a miniscule 0.01.

Need a New Touring Kayak?

Is that trusty old touring kayak getting a little long in the tooth? Are you finding it harder and harder to keep up with your paddling companions? Are you finding that your current boat just doesn't have the storage capacity for those long, multi-day excursions? Or are you in the market for your first sea or touring kayak?

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If you've got a moment, check out one of our recommended merchants. You'll be pleasantly surprised at what you find.

Touring kayaks from Backcountry.com
Shop Backcountry.com for a great selection of name brand touring kayaks, including Perception and Dagger.

Tips & Tricks

Stuff those bulkheads

You may have noticed, but loading up the aft compartment on your touring kayak can significantly improve handling. The only problem is that gear in a half-filled compartment tends to shift when your boat rolls, which can cause real problems when you try to right your kayak. One solution to this problem is to fill that unused space with air bags. And if you really want to stuff that aft stowage area, try loading it through the cockpit instead of the hatch.