Developed more than a decade ago by Proctor & Gamble, and used in municipal as well as humanitarian applications, the process introduces iron sulfate and calcium hypochlorite in a powder form to water tainted with sediments and microorganisms. Unlike iodine or other typical treatments used in the outdoors, the P&G process pulls all the gunk in water together, coagulating nasties including cysts, microbes, viruses and bacteria into clumps you can then filter out.
As a two-step process, calcium hypochlorite, a bleaching agent, kicks in after the initial coagulation to kill off any remaining gastrointestinal disrupters. The final result is water that's 99.99 percent pure, according to data from PUR parent company Reliance Products, which needed U.S. Environmental Protection Agency approval before introducing the chemically potent product to the consumer market earlier this year.
Scott Mitchell, a spokesman for Reliance, explains the iron sulfate coagulation process by referring to the chemical reaction as a "dirt magnet." "It reacts in the water and pulls everything in suspension together in clumps," he said.
I tested the product with tannin-tainted water from a stream in northern Wisconsin. Flowing from the depths of the Chequamegon National Forest, the water was dark brown and speckled with sediments and microorganisms swimming free.
Working with the PUR Clean Drinking Water Kit--a $28.99 do-it-yourself water treatment plant that includes the PUR chemicals, stir sticks, filtering clothe and containers--I mixed and stirred and followed directions for 45 minutes. I watched the clock for timed waits while chemical reactions triggered. Slowly, the brown water began to turn clear, with sediment clumping together in a disgusting reddish mass at the bottom of the container.
Filtering the flocculent--the technical term PUR uses to describe the clumped putridity--was a pain. I worked with a friend near our campfire for 20 minutes, pouring the water through a cloth that kept clogging up. The cotton caught the flocculent fine, though it allowed only a small stream of clean water through its tight fabric weave and into the vessel below.
Another annoyance: The collapsible buckets that come with the Clean Drinking Water Kit have small openings, making pouring and filtering slow. The foldable containers are difficult to clean, too, as deep accordion creases in the plastic catch and hold flocculent that's then nearly impossible to wash out.
But after some struggle, the PUR method yielded water that was indeed quite clean. In front of my eyes, the final product transformed from a container of gloppy river water into a gallon of sparkling, crisp H2O that seemed siphoned from a spring.
PUR (www.purpurifierofwater.com) sells two Purifier of Water products, including the kit I tested as well as a $14.99 package that has chemicals for six treatments and a cotton filter cloth, though no containers.
While the process is cumbersome, Purifier of Water is a superior way to clean large quantities of suspect liquid. My main beef was with the Clean Drinking Water Kit's containers. The chemical reaction in dirty water was amazing to watch, and the mix-and-stir process is easy to follow and manageable if you have a half-hour or so to work with your water in camp. Next time, I'll use a custom configuration of buckets, vessels and a larger cotton cloth to speed the mixing and filtering steps.
Compared to pumps and other traditional chemical treatments like iodine, PUR's system is purportedly the most thorough. There is almost no smell or chemical aftertaste, just hydrogen and oxygen mixed and pure, sloshing, swirling and ready to drink in a bucket below.
Stephen Regenold writes The Gear Junkie column for eight U.S. newspapers; visit thegearjunkie.com for video gear reviews, a daily blog and an archive of Regenold's work.