Lightweight backpackers are generally well-tuned to current trends in water treatment. The astute backpacker will seize any opportunity to save water weight, because he knows well enough the pain of dragging several liters of water unnecessarily up a wilderness incline pocked with snow melt pools and rivulets of clean mountain water. Likewise, traditional water treatment technologies, such as pump-style water filtration devices, are viewed with some disdain by lightweight hikers who consider the extra half pound or more better spent on carrying more chocolate, an extra insulating layer, whisky, or perhaps, a camp chair.
Water treatment technologies that have rapidly gained affinity by lightweight backpackers are based primarily upon chemical, rather than physical, processes. Certainly, iodine tablets remain the core "ultralight" solution among the mass market, with chlorine dioxide (e.g., Aqua Mira, KlearWater, and MicroPur) rapidly gaining ground on iodine within the ultralight community for its perception of better taste and greater efficacy. In addition, new technologies based upon the electrochemical activation of mixed oxidants (e.g., MSR Miox) and the electrical activation of ultraviolet light (e.g., SteriPen and AquaStar) have gained favor for their ability to appeal to the increasing desire for "cool gadgetry" by modern hikers. In addition, a distinct advantage of UV irradiation technologies is their ability to inactivate protozoan cysts rapidly (on the order of minutes, vs. hours for chemical methods).
The bottom line is that in the past thirty years, our water treatment kits haven't gotten lighter, and in fact, are probably heavier (when you consider the inclusion of gadgetry such as pumps and electrical devices). The question remains whether or not the incidence of intestinal distress has actually decreased with new technology, or whether the media's increasing coverage of water treatment in the past two decades has served only to fuel hikers' desires for more efficacious treatment methods.
Regardless of how contaminated you believe wilderness water to be, or how efficacious you believe your treatment choice to be, there is no doubt that the state of water treatment technologies available to backpackers is in a state of flux relative to what it was three decades ago (when our only options were bleach drops and iodine tablets) or even a decade and a half ago (when we had pump style filters at our disposal).
In the days of iodine and bleach drops, the mechanism by which a microorganism (such as a bacterial cell) was killed included the oxidation of the cell wall/membrane, a process akin to blasting the living nasty with the molecular equivalent of a howitzer. When filtration devices hit the market, the attack was a bit more benign: entrap the little buggers in a porous matrix where they became physically separated from the "clean" water. Chlorine dioxide provided more effective oxidation because it more specifically targeted cellular tissues instead of being consumed by inorganic detritus (e.g., silt particles) and exopolysaccharides (the glue that forms the protective matrix around bacteria in their biofilm mode of growth). UV light is the only technology available that can rapidly inactivate protozoan cysts.
All of these technologies have been available for the past two years, but are not without their limitations. Iodine and bleach impart foul tastes to the water, are less effective in turbid waters, and require abysmally long treatment times to inactivate protozoan cysts; filters clog with sediments, fail to remove viruses, are heavy (in the case of pump filtration systems) or slow to use and/or cumbersome (in the case of gravity filtration systems), and bulky; chlorine dioxide requires two chemicals to be mixed in the field (or uses a premixed solution with a limited shelf life); and UV light requires batteries, are relatively heavy (a quarter pound or more), and limited in their ability to treat large water volumes and/or treat water in a variety of container geometries.
So what do lightweight backpackers want?
Aficionados of filtration devices wish for lighter units capable of pumping water faster. Chemical treatment fans would certainly appreciate the ability to inactivate cysts before dehydration set in while waiting for their water to be treated. UV treatment fans wish for devices that can be used with different bottle types and are lighter.
We can't promise that new technologies announced at Outdoor Retailer Summer Market 2007 are going to deliver on all of these promises, but the prospects are encouraging, and we are getting ever closer to a holy grail in water treatment.
Meridian Designs (Aqua Star) mUV
Meridian Designs (Aqua Star) mUV Ultraviolet Light Water Purifier
Generating no small bit of excitement among our staff is the release of the Meridian Designs (Aqua Star) mUV, a 2.4 oz (68 g) compact miracle of UV disinfection.
The mUV is the lightest ultraviolet water purifier currently available. It bears resemblance in both form and function to a fishing bobber - and is designed to float in a bottle or pan of water during the UV purification process. Its rechargeable Lithium-ion battery will treat a liter of water in less than 2 minutes, and provide 15-20 liters of water on a single charge.
The mUV uses an incandescent UV-C bulb to deliver its deadly rays. Inside the housing, there is a single RCR 123 Li-ion rechargeable battery; two small wires with gold-plated magnets allow the purifier to be attached to any single cell battery for recharging. A D-cell is the most cost effective recharge option, and will recharge the unit ten times. An AA battery will supply only 1-2 charges, but this is probably enough to power the unit through the short backpacking trips (long weekends) that most of us are accustomed to taking.
The mUV is simple to use: press a button on top of the unit for two seconds and the unit starts its cycle. It's best to use water without sediments, which tend to block UV rays and create hiding places for microorganisms. You should agitate (swirl, stir, or otherwise mix) the water while it is being treated. Use multiple cycles to treat a larger volume of water.
Although the unit is claimed to fit into and plug the opening of a standard 1-2 liter soda bottle or Platypus flask (commonly used by LW backpackers, in addition to other 28mm screw thread bottles), the tip of the unit containing the light source barely entered our Platypus bottles, so we wonder how effectively the mUV is really going to be with 28mm bottle systems. Our concern is that with the UV unit tucked away in the bottle's back alley will prevent mixing well enough to ensure adequate UV treatment of all of the water in the bottle. There's no problem for any water container with a larger opening, such as a Nalgene Cantene.
At an MSRP of $49.95, the mUV seems to provide solid value, especially when compared to the 3.6-oz SteriPen Adventurer, which will eat $130 of your gear budget.
Highlights: Meridian Designs mUV
- What's Hot: Cool technology that kills cysts fast.
- What's Not: Relies on rechargeable battery power, poorly efficacious in turbid water, questionable compatibility with bottles having 28mm screw threads or smaller, pre-production testing is revealing some bugs.
- Weight: 2.4 oz (68 g) (our measured weight is 2.5 oz / 71 g with its protective cap; the included prefilter/storage bag adds 0.2 oz / 6 g)
- Dimensions: 4.50 in (11.4 cm) long x 1.75 in (4.4 cm) wide
- MSRP: $49.95
Acknowledgment Thanks to Will Rietveld for collecting the info for this article on the mUV system.
Mountain Safety Research HyperFlow Filter
Mountain Safety Research HyperFlow Filter
Using the MSR HyperFlow is like operating a compact bicycle pump. In fact, when we operated the filter, it felt like a Blackburn Airstik in form, size, and pump-action function.
Immediately apparent is the compact size of the HyperFlow. Compared to the gold standard in backpacking water filters, the Katadyn Hiker, the MSR HyperFlow is downright wispy. Its construction is solid, however, and its build quality certainly reflects MSR's commitment to durability, and, ahem, weightfulness - the unit is not "ultralight" by any means, and tips the scales at 7.4 oz (210 g).
Now, don't go flashing your SUL card quite yet - you need to consider this half pound filter in context with the industry's gold standard - the Katadyn Hiker. Compare for yourself:
|Katadyn Hiker||MSR HyperFlow|
|Weight||11.0 oz (312 g)||7.4 oz (210 g)|
|Output||1 liter/minute||3 liters/minute|
|Filtration Porosity||0.3 μm||0.2 μm|
So, if the 33% weight reduction doesn't grab your attention, maybe the 300% increase in flow rate will. If MSR's claims are to be believed, then the HyperFlow is aptly named and you could be drinking a liter of clean water in a matter of 20 seconds after starting to pump, thereby mitigating one of the most unfavorable ills of Backpacking Heavy: filtration fatigue syndrome.
Highlights: MSR HyperFlow
- What's Hot: Pump-style water filter that is markedly smaller, lighter, and faster than what we've known for the past eight years.
- What's Not: Weight, duh? And undoubtedly prone to all the problems associated with filtering turbid water with sediments - and $100? My goodness, that's a chunk of change compared to the $60 Katadyn Hiker.
- Weight: 7.4 oz (210 g)
- Output: 3 liters/minute
- MSRP: $99.95
End Note: MSR also released a gravity filter at the show that weighs 11 oz / 312 g (!)
McNett Aqua Mira Frontier Pro Filter
McNett Aqua Mira Frontier Pro Filter
OK, back to lightweight reality for a moment.
Let's skip the pump action and move towards instantaneous water use at the source. That's exactly the philosophy of McNett's Aqua Mira Frontier Pro Filtration unit: fill up your bottle, screw the device to it, and suck water through the filter.
I know, I know. Sucking, well, sorta sucks.
But hear me out.
McNett has claimed that the Frontier Pro delivers suckable water at a reasonable rate that won't have you rating the device's suckability factor so low that it would suck for you - or McNett. I'll have to table the claim until I get a working model in my hands, but for now, I'm optimistic that this will be more than just a facial exercise device.
What I really like about the device is its form factor. It's an inch (2.5 cm) in diameter and only 5 in (13 cm) long - about the size of a fat man's Cuban. To use it, simply screw it to a bottle full of your favorite dirty water (the Frontier Pro's screw mount is compatible with any 28 mm bottle thread, including Platypus and most soda bottles), tip, and ... well ... suck. The bite valve is quite comfortable and by itself offers no resistance whatsoever to water flow. The valve is protected by a cover that remains connected to the filter with a rubberized hinge that also gives the unit a comfortable grip.
OK, here's the cool part.
Pull off the bite valve, turn the bottle upside down, and you have a gravity filter. No hoses, no special fittings, no fuss. Aesthetically, it's beautiful. But I'll reserve a performance assessment until I get my hands on a production version.
The Frontier Pro weighs 4 oz (113 g) and will retail at $19.95.
Highlights: McNett Frontier Pro Filter
- What's Hot: Sophisticated straw or gravity filter that is compatible with popular 28mm screw thread bottles, inexpensive, lightweight
- What's Not: My nervousness about its suckability (pending review of a production model); small size = lack of filter surface area to mitigate fouling by sediments
- Weight: 4.0 oz (113 g)
- Output: unknown
- MSRP: $19.95
Reliance PUR Chemical Treatment
Reliance PUR Chemical Treatment Packet
All water treatment methods available to backpackers - iodine tablets, chlorine dioxide tablets and solutions, filtration devices, UV devices - suffer from the presence of sediments in the source water. Chemical methods are variably effective in turbid waters, and are largely a function of water chemistry, sediment type, and disinfection mechanism. UV devices fail to disinfect turbid waters where fine sediments are agglomerated into larger particles that can hide pathogenic microbes within the particle porosity. And filters with pore sizes fine enough to remove nasty microbes are simply incapable of being resilient enough to withstand the filtration of meaningful amounts of turbid water.
In short, treating turbid water remains a great challenge for the backcountry traveler.
Enter stage left: a collaborative partnership between Procter & Gamble and Reliance to bring PUR to the consumer market. PUR is mixture of chemicals in powdered form that comes in a sealed foil packet (weight per packet is 0.14 oz / 4 g) that is used all at once to treat 2.5 gallons (9.5 liters) of water. To use it, rip the packet open, empty the contents into your water container, mix it for five minutes, let flocculated sediments settle for 5 minutes, decant the clear water through a cloth filter into a clean water container, and wait 20 minutes before drinking.
OK, here's the claim:
PUR removes dirt, cysts, and chemical pollutants; it kills viruses and bacteria. Water is ready to drink after 30 minutes. Here's how:
Upon emptying the packet into the source water container, the chemicals are mixed into the source water for a period of five minutes. This period of mixing promotes uniform distribution of the chemicals that is required to begin the process of coagulation. PUR induces a change in the water chemistry (facilitated by the introduction of ferric sulfate as a coagulant) that results in the coagulation of suspended solids (the process induced by a change in chemistry under intense mixing conditions that results in the destabilization of suspended solids, causing their precipitation into larger particles) followed by their flocculation (the process under light mixing conditions that results in the growth of particles into large, fluffy masses that become settleable when mixing is stopped).
After five minutes of mixing, the solution is allowed to settle for a period of five more minutes. During this time, the flocculated sediments (which resemble particles the size and texture of popped popcorn) sink to the bottom of the container. After the majority of these particles have settled, the clear water is decanted through a cotton "filter" (e.g., the backcountry traveler might use a bandana, t-shirt, or similar item) into the clean water container. Then, calcium hypochlorite (which creates free chlorine in solution) acts as the disinfectant to kill bacteria and viruses remaining in the solution, a process that takes about 20 minutes. It is presumed (generally, rightly so) that larger microbial particles, including protozoan cysts and multi-celled organisms, become entrapped in the flocculated particles and settle out of the solution.
If this process sounds familiar (coagulation-flocculation-settling-filtration-chlorine disinfection), then it should - this is the basic model for 95% of the water treatment facilities in the United States.
In short, PUR is the only product that is capable of removing sediments and their associated contaminants (including chemical pollutants and multi-celled microorganisms) in a manner that does not rely on the effective filtration of these contaminants and sediments through small-pore filtration devices. Thus, therein lies one of the greatest benefits of PUR over filtration units.
At this time, the obvious limitation to PUR is its minimum treatment volume: 2.5 gallons (9.5 liters). This sort of volume is absurd for the vast majority of solo hikers traveling in northern latitudes or mountainous areas, where water is prevalent. And, the packets can not be opened and redistributed, or partially used. Exposing the chemical powder to the combination of moisture and oxygen rapidly deteriorates the hypochlorite in the mix and efficacy will be destroyed in short time.
However, for desert hikers, hikers wanting an in-camp solution for treating larger volumes, larger hiking groups, institutional groups (e.g., NOLS, BSA, etc.), PUR offers a viable alternative to other methods on the market, which, for treating 9.5 liters of water at a time (think about the time required to pump 9.5 liters of sediment-laden water), is not only reasonably economical (PUR will treat water at a cost of around $0.26/liter), but extremely light (0.4 g/liter, or 0.015 oz/liter). Initially, I balked at the 2.5 gallon minimum treatment volume, but then the wheels started spinning: how I wished I had this on my CDT hike through New Mexico where I drank from stock tanks, or my Escalante River packrafting trek where the river was running high with water that looked like chocolate milk, or my countless trips with friends where we'd pump for hours on end to get enough water for the six or eight of us for dinner and breakfast.
PUR is only new to the outdoor market - they've been around for more than half a decade, actually, focusing on applications related to disaster relief and providing safe drinking water to developing countries. However, I think this product market (the outdoor industry) will evolve in a meaningful way for Reliance, and it won't be long before we see the technology scaled down for smaller volumes.
Highlights: Reliance PUR
- What's Hot: Simply the most effective means of removing sediment in turbid waters; an efficient treatment method for larger groups, desert hiking, and base camping.
- What's Not: Minimum water volume is too high for the general backpacker; the system is based on "old" disinfection technology (chlorine); I have some concern about the inadequate disinfection of cysts that were not originally removed in the coagulation/flocculation process.
- Weight: 0.14 oz (4 g) per packet (treats 9.5 liters of water)
- Active Ingredient: Calcium Hypochlorite
- MSRP: $14.99 (includes six packets)
Future Trends in Backcountry Water Treatment and Practices
The new treatment technologies announced at Outdoor Retailer Summer Market 2007 represent significant steps forward in the advancement of the product niche as a whole. The McNett Aqua Mira Frontier Pro Filter brings dual use (gravity and drinking straw type filtration) into one device and miniaturizes it into a lightweight, compact package that integrates well with our other gear (namely, 28mm screw thread bottles). The MSR HyperFlow Filter reduces weight and size and dramatically increases the speed (and reduces the effort) of the process of creating clean water from a contaminated source. The Meridian Designs mUV device further decreases the size and weight of UV disinfection devices, and we can certainly expect further reductions in the near future as economies of scale allow for the miniaturizing of the unit's electronic circuitry and power supply. Finally, with Reliance PUR, we have a completely new technology that takes a fresh look at treatment and may fill a real need for large groups and turbid water sources.
In addition to further reductions in size and weight (in the case of physical devices), and reductions in cost (in the case of chemical methods), the future of backcountry treatment technologies may feed upon two emerging social trends:
- The need for chemical free solutions that pose zero health risks. Recreational backcountry users are concerned about their health and welfare, as indicated by the explosion of organic and natural foods demands, homeopathic healing products and services, and a general acceptance of accountability for a healthy lifestyle.
- The need for extremely fast solutions that can deliver drinkable water only moments after arriving at the water source. Welcome to the "I want it, and I want it now, world." More importantly, treatment technologies capable of delivering water instantly will have a dramatic impact on pack weights: hikers may be more likely to stop, scoop, treat, and drink, rather than carry pounds of water across miles of trail.
In practice, nothing beats consuming water at the point of source in order to save weight. However, I think we'll see the percolation of recent research in the physiology area, combined with the development of new nutritional supplements that maximize water absorption, into the realm of the "serious recreational" backpacker who wants to maximize their performance by remaining hydrated with a minimum of water intake.
However, we'll have to be satisfied with what's available now, and what's coming around the corner. But, we should feel awfully lucky. This is an exciting time for backcountry water treatment and few areas of technology offer so many options at so many price points, weights, and levels of effectiveness.
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