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Choosing A Water Filter - Feel free to ask any questions.
Why do we need a drinking water system?
More people are using drinking water systems while camping, backpacking and traveling. Why?
* Safety. Unfortunately, most lakes, rivers and streams are full of microorganisms that can make you sick. Drinking water systems can eliminate these contaminants and make the water safer to drink.
* Protect Yourself. Because you never know what's in the water.
* Freedom. Be self-sufficient with a drinking water system. As long as there is a water source, you can have safe drinking water. And, lightweight drinking water systems won't weigh you down like carrying extra water.
What's really in the water?
Microorganisms are the primary threat in untreated water sources. They may be in any lake, river or stream, even if the water looks clean. Microorganisms generally come from animal waste and may be spread by rain and run-off.
Beware of these 3 types of microorganisms:
Protozoa (2 microns and larger).
Protozoa are the largest microorganisms. Therefore, they are the easiest to filter out of the water. However, their protective shell makes them resistant to iodine and chlorine treatment alone. One common protozoa, Giardia, causes "Beaver's Fever.
* Giardia and Cryptosporidium
Bacteria (.2 microns and larger).
Bacteria range in size from 0.2 to 10 microns. Large bacteria may be removed by most microfilters, but smaller bacteria can only be eliminated by a very small micron size microfilter or a purifier. Bacteria are responsible for diseases such as Cholera and Typhoid Fever.
* E. Coli and Salmonella
Viruses (.004 microns and larger).
Viruses are the smallest microorganisms and cannot be reliably removed by filtration. It was traditionally thought that viruses aren't a concern in North America, but that opinion has changed. Wilderness studies suggest that 60% of all back county illnesses are actually caused by bacteria and viruses. Viruses can cause serious health problems, such as Hepatitis, Polio and Norwalk Virus. Viruses can be eliminated from water with purification, chemical disinfection, or boiling.
* Hepatitis A, Polio, and Norwalk Virus
What is the best way to make water safe to drink?
* Purifying:
Combines chemical disinfection with filtration to eliminate all three types of microorganisms.
* Boiling:
Bring the water to a full boil to kill microorganisms. requires energy source and takes time
Iodine Tablets:
* Add 1 or 2 tablets per quart and wait 20 minutes to kill the microorganisms. Takes time and adds foul taste. limited effectiveness against Giardia and not effective against Cryptosporidium.
* Filtering:
Microfilters may remove protozoa and most bacteria. Doesn't remove viruses. May require frequent cleaning due to clogging.
How do I choose a drinking water system?
Use the Drinking Water Safety Guide to help you choose the best products for your needs. It organizes drinking water systems according to the #1 concern: safe water.
Drinking Water Safety Guide Water System Microorganisms Eliminated Microbiological Micro Rating:
·Protection Level No. 1 Purifier Eliminates Viruses, Bacteria and Giardia .004
·Protection Level No. 2 Microfilter Eliminates Giardia and Most Bacteria 0.2 to 1.0
·Protection Level No. 3 Filter Eliminates Giardia 1.0 to 4.0
Purifiers: #1
Highest safety rating Eliminates Viruses, Bacteria and Giardia, no matter what micron size
Microfilters: #2
# 2 safety rating Eliminates Giardia and Most Bacteria, depending on their micron size.
Filters: #3
# 3 safety rating only eliminates Giardia and microorganisms larger than 1 micron.
Okay, so how do you choose the right one?
1. Consider How Much Protection You Want
It's impossible to know for sure if a given water supply is free of contamination. But bacterial and protozoan contamination has been estimated to be present in 90% of the United States' surface water. And water-borne viruses may be found anywhere where humans have come into contact with the water supply.
Filters - All of the water filters that EMS carries provide reliable protection against bacteria and protozoa (one new model also provides reliable protection against viruses!). Filters are the easiest, most economical method of making water safe to drink in situations where viral protection is not needed.
A Note on Pore Size
The size of the holes, or "pores", in a filter determine which microorganisms get caught and which sneak through. Most filters have a small range of hole sizes. Absolute pore size refers to the size of the largest (least effective) holes. This measurement tells you which critters will be caught and which won't.
Unfortunately, some manufacturers advertise nominal (average) pore sizes instead of absolute sizes, which can make the whole pore size issue very complex. When comparing the effectiveness of different filters, concentrate instead on which water-borne nasties the unit claims to eliminate and which it doesn't.
Every water filter (and purifier) that EMS sells has packaging that describes which microorganisms it can protect you from. Be sure to read this information carefully before choosing a specific model.
Purifiers - Water purifiers offer the very best protection available from contaminated water in the backcountry. Purifiers usually provide reliable protection against bacteria, protozoa and viruses. But is this extra protection worth the extra cost? It depends on your plans.
Choosing A Water Filter
You are at risk for viral infection any time humans have come into contact with your water supply (NOTE: viruses can be spread by everything from urinating to brushing your teeth to spitting in a stream).
This means situations like:
* Crowded recreation areas where sanitation systems may become overloaded from time to time.
* Areas where infants may be in the water.
* Backcountry sites where backcountry visitors may not have disposed of their waste properly.
* Developing countries with basic sanitation systems.
Areas that are susceptible to natural disasters like floods and earthquakes (which could overwhelm sanitation systems).
Quite simply, purifiers are the best choice for any backcountry traveler who doesn't want to take any chances with their water supplies. Remember -- you never know for sure what's been going on up stream!
2.Consider How Much Water You'll Need
If you only backpack a few times a year, focus your attention on smaller, less expensive filters/purifiers designed to handle a limited amount of water. You may need to replace the filter elements in these models from time to time, but you'll still come out ahead in the long run. If you plan on using your filter/purifier more often (10-20 times a year), it may be more cost effective for you to choose a more expensive unit that's designed to last longer between filter replacements.
Also keep in mind as you compare filter/purifier models that different designs work at different speeds. If your trip plans involve difficult terrain, dry conditions and/or large groups of people, look for a model that can process a lot of water quickly. If you're planning shorter trips and/or smaller groups, you maybe happier with a lighter, smaller, less expensive model.
3.Consider Size and Weight
Keep in mind that you'll be carrying your filter/purifier everywhere you go. Balance your desire for high water output and ease of use with your desire to keep your backpack light.
4.Consider Ease of Operation
Water filters/purifiers come in a variety of styles. When performance levels are similar, the decision between them is often a matter of personal taste. To decide between models, consider how easy each one is to use. Ask yourself questions like:
·How easy is the filter/purifier to set up and operate?
·If it's a pump design, how easy is it to pump?
·Can it be operated easily by a single person? (try it out for yourself and see!)
·Is it possible to connect a water container directly to the unit? If not, how easy is it to get the treated water into your water jug?
·Can the filter unit be cleaned to extend its usable life? How easy is it to do?
·What about basic maintenance procedures? Can common problems be fixed in the field?
NOTE: If you plan on setting up camp and staying put for a while, you may want to consider a large-volume, gravity-driven system instead of one that you have to pump. Gravity-driven systems tend to be bulkier and slower than hand-held units. But they can process a large volume of water while you're out exploring, and you don't have to lift a finger!
5.Consider Cost
The most expensive water filters/purifiers are often the most cost-efficient when you consider their performance and longevity. If you plan on backpacking for a number of years, consider paying a little more up front so you can save money further down the trail. When comparing costs, look at:
* The overall price of the unit.
* The amount of water that it can treat before the filter must be replaced.
* The cost of replacement filter/chemical elements.
Also keep in mind that some filter/purifier elements can be "scrubbed" from time to time to clean out pores and extend their useful life. Others cannot.
Pre-filter - Usually located at the end of the intake hose or just before the main filter. Pre-filters strain out the largest particles and cut down on wear and tear to your main filter element. Most pre-filters can be rinsed from time to time to remove caught particles.
Depth Filter - These are blocks of filtering material, honeycombed with small passages. Water flows through the passages and microorganisms are caught inside. Some depth filters can be cleaned to improve longevity, others cannot.
Surface/Membrane Filter - Membrane filters are perforated surfaces that strain out particles as the water passes through. Surface/membrane filters cannot be scrubbed clean.
Source: http://www.ifshtf.com/forums/showthread.php?t=67
Board index » SHTF & SURVIVAL / PREPAREDNESS -- LONG TERM & SHORT TERM » Survival & Preparedness Basics » Water » Purification, Distillation, Filtration, Sterilization
Water Filters - explained
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 SHTF Expert 
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Joined: Mon Feb 01, 2010 1:45 pm Location: Detroit, Mi Blog: View Blog (0) |
 Posted: Wed Mar 24, 2010 3:10 pm
From Apocalypse to Zombies, we've got your A-Z.
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Joined: Sun Oct 28, 2007 3:22 am Location: North Carolina Blog: View Blog (31) |
Posted: Tue Dec 21, 2010 7:37 am
 made this a sticky
"When injustice becomes law, resistance becomes duty..” Thomas Jefferson
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Posted: Tue Dec 21, 2010 8:27 am
Because we are on a shallow well, we mostly rely on simple filters in the form of pitchers and water bottles with the filters built in. I pick up the bottles when i see a good deal on them at gun shows or in sports stores. I also have filter straws in our bug out bags.
On a mountain top in western Mass.
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SHTF Expert
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Joined: Mon Feb 01, 2010 1:45 pm Location: Detroit, Mi Blog: View Blog (0) |
Posted: Tue Dec 21, 2010 10:08 am
Thanks. If anyone has any questions, feel free to ask. I've used a variety of water filtration products as I'm an avid backpacker.
My newest toy is a MSR Miox which serves alongside my Katadyn pocket. From Apocalypse to Zombies, we've got your A-Z.
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