Begining Lesson #6 Understanding Water Filteration

[RICHFL]

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Understanding Water Filtration

1. 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. Understanding how a Drinking water systems works 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.

2. 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. 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.

a. 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.

b. 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 micro-filters, but smaller bacteria can only be eliminated by a very small micron size micro-filter or a purifier. Bacteria are responsible for diseases such as Cholera and Typhoid Fever.

c. 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.

3. What is the different ways to make water safe to drink?

a. Purifying: Combines chemical disinfection with filtration to eliminate all three types of microorganisms.

b. Boiling: Bring the water to a full boil to kill microorganisms. requires energy source and takes time

c. Chemicals: Follow the directions on the bottle. following the direction for using Bleach at the bottom of this article. Takes time and adds foul taste. It has limited effectiveness against Giardia and not effective against Cryptosporidium.

d. Filtering: Micro-filters may remove protozoa and most bacteria. Doesn't remove viruses. May require frequent cleaning due to clogging.

4. How do I choose a Portable Water Filtering System for bugging-out? Since you will be on the move and need to replace the limited water you will carry it is imperative to have the best equipment available for your use.

a. 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:

(1) Protection Level No. 1 Purifier Eliminates Viruses, Bacteria and Giardia .004
(2) Protection Level No. 2 Microfilter Eliminates Giardia and Most Bacteria 0.2 to 1.0
(3) Protection Level No. 3 Filter Eliminates Giardia 1.0 to 4.0

b. Purifiers: Has highest safety rating, by eliminating Viruses, Bacteria and Giardia, no matter what micron size

c. Microfilters: Rated #2, it will eliminate Giardia and Most Bacteria, depending on their micron size.

d. Filters: Rated #3 only eliminates Giardia and microorganisms larger than 1 micron.


e. Filters - All of the water filters that sell in the USA 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. Note 1

f. 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.

g. Every water filter (and purifier) has packaging that describes which microorganisms it can protect you from. Be sure to read this information carefully before choosing a specific model.

h. Purifiers - Water purifiers offer the very best protection available from contaminated water in the back-country. Purifiers usually provide reliable protection against bacteria, protozoa and viruses. But is this extra protection worth the extra cost? It depends on your plans.

i. 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.

j. 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.

k. 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. Note 3.

l. 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?
·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?

m. 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. Note #4.


n. 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.

o. 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.

p. Surface/Membrane Filter - Membrane filters are perforated surfaces that strain out particles as the water passes through. Surface/membrane filters cannot be scrubbed clean.


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DETAIL INFORMATION ON WATER, WATER FILTRATION SYSTEMS FOR YOUR RETREAT AND A PRACTICAL HOME MADE FILTER SYSTEM:

1. Consider what makes water unsafe.

a. The Contaminants: There are two main classifications of contaminants we need to concern ourselves with – organisms (living creatures) and chemicals (which may be organic or inorganic in nature but are not alive).

(1) Organism Hazards: There are a large number of types of organisms that can exist in the water. The hazards in drinking water are small – very small. I’ll include rough size ranges when describing them. For consistency I’ll give all sizes in microns (a micron is one thousandth of a millimeter or one millionth of a meter. These include:

(2) A virus is a piece of nucleic acid wrapped in a coat of protein. It is not a cell and can only reproduce and grow by infecting a host where it inserts its nucleic acid into host cells. Examples of water borne viruses include Hepatitis and Rotavirus. A virus is the smallest of the organic hazards we are discussing – they range in size from 0.3microns to 0.01microns.

(3) Bacteria are single celled organisms with a complete set of nucleic acid (RNA and DNA) and are much larger than viruses (up to 100 times). Over 90% of bacteria are harmless or beneficial to humans but some are dangerous. Examples of dangerous bacteria include Cholera and Typhoid. Bacteria measure 0.5microns to 5 microns

(4) Protozoa are single celled creatures. Larger and more complex than bacteria, they are commonly found in both water and soil. They are generally invisible to the naked eye – they range in size from ten microns to half a millimeter (or 500 microns) Some protozoa have the ability to form cysts.

(5) A cyst is a hard walled form of a micro-organism such as Giardia or Cryptospyridium, These cysts can survive in water or fecal matter for a long time and in conditions that the protozoa would not. Chlorine and Iodine for example may not reliably kill cryptospyridium cysts

(6) Many chemicals can be found in water – these include metals (lead, arsenic, mercury), nitrates / nitrites and many more. Their presence can be natural or the result of human activity. Mining can cause the presence of metals in the water supply (particularly in less regulated parts of the world), agricultural run off of fertilizers and pesticides are another common cause of chemical pollution. Chemical contaminants have to be separated from the water to render it safe since they cannot be killed as organisms can.

b. Boiling Water: Heating water to a high enough temperature for a long enough time will kill all dangerous organisms. Advice from reputable sources varies but consensus seems to suggest that raising water to 100C will have killed all bacteria and viruses. Cysts are a little tougher and advice is to maintain 100 degrees C for one minute to be safe. The amount of “boil time” advised by “authorities” varies. There are two reasons for this:

Altitude (and consequential air pressure) alters the boiling point of water. To take an extreme example, the pressure at the summit of Everest is about a third of sea level air pressure. At this altitude, water boils around 70C. Since 82C is the temperature at which bacteria are instantly killed, the problem is obvious. US EPA advice is that cysts which are probably the toughest of the organisms will be killed by ten minutes of exposure to water at 70C.

Turbidity. This is mucky murky water to you and me. Many micro organisms are found in soil. If soil particles are floating in water, they can insulate the organisms they contain from the rise in temperature for a period of time. The murkier the water, the longer the boil time should be sustained. Better yet is to use a coarse filter to remove larger soil particles.

Conclusion: Clear water brought to a rolling boil at low altitude will be safe from organisms. The higher the altitude and the murkier the water, the longer a boil should be maintained (to a maximum of 15 minutes for dirty water whilst standing on the summit of Everest).

c. Water filtration:

(1) Coarse filtration. Coarse filtration will not remove either organic or chemical hazards since the barrier apertures are large enough to allow even protozoa to pass through. What coarse filtration will do however is screen out all but the finest of the particulates that cause turbidity. This will render boiling and chemical sterilization far more effective and also hugely improve the pat-ability of water. The most common form of coarse filtration is called in the British military the Milbank bag – a tightly woven canvas bag with a design optimized for coarse filtration.

(2) Fine Filtration. Fine filtration will certainly remove protozoa and cysts and the better quality filters will also remove bacteria. To look out a quality fine filter, look for “absolute” filtration of 1 micron or less. The most common form of fine filtration is a ceramic filter (often used in combination with other approached described later). A high quality ceramic filter will last indefinitely (although other combined products will not). It is important to note that fine filters, because they can trap bacteria, can become a breeding ground and source of contaminants. In order to alleviate this some form of secondary barrier is often included in the fine filter – often silver is used to prevent the bacteria surviving. A ceramic filter will also form a barrier to some metals and organic matter (but by no means all).

(3) Ultra Fine Filtration. There are portable filters available that can filter out viruses. These are relatively new to the market and are still relatively expensive. I addition there is the process known as reverse osmosis. This is a very fine filter which water molecules are forced through with a pressure of 40 – 80 psi. Reverse osmosis can remove not only viruses but also salts (e.g. producing fresh water from salt water) and metal salts.


d. Chemical. There are a variety of chemicals that will kill micro organisms – perhaps the most common are Iodine and Chlorine based products.


(1) The cheapest method of adding chlorine to water is to use plain, unscented household bleach (5% sodium hypochlorite). Add one drop (0.05ml) per liter – two if the water is cloudy and leave for at least 30 minutes. This works best in warmer water and may not be effective against protozoa and cysts. Household bleach is not the best solution for traveling as persistent shaking can result in loss of chlorine activity.

(2) Chlorine tablets. Tablets are far more convenient to carry, less subject to degradation by motion than household bleach they are a slightly different chemical (Sodium dichloroisocyanurate). The most common form uses 1 tablet per liter (although I would use two in cloudy (turbid) water). Water should be left for 10 minutes after the tablet has been added.
Puritabs (the most common type) claim effectiveness against Giardia.

(3) Iodine. Iodine is considered slightly more effective than chlorine based chemical approaches against protozoa and cysts, however even iodine based preparations did remove more than 90% of cysts in some tests unless left for 24 hours.

There are some health concerns over prolonged use of iodine (with the potential to lead to goitre). It is wise for young children, pregnant people and those with iodine allergy (or shellfish allergy which can be an indicator) to avoid the use of iodine-based preparations.

Some find the taste of iodine preparations unpleasant and use a “neutralizer” to remove the taste. It should be noted that adding the neutralizer renders the iodine ineffective so it should only be added after the correct waiting period (30 minutes to 1 hour if in doubt). It is worth mentioning that the “neutralizer” is soluble ascorbic acid (Vitamin C). Soluble vitamin C from the pharmacy will work just as well (and cost less). The risk of using a neutralizer is that any left in your water bottle will reduce the efficacy next time iodine is used.

Tincture of Iodine: Tincture of Iodine (Alcoholic Iodine Solution BP) - this is readily available from pharmacies and contains (generally) 2% iodine. Suggested doses vary, but to deactivate cycts, five drops per litre and a half to one hour wait period allowed at normal temperatures (more if cold). Note 5

Iodine based tablets. The most common type of these is “Potable Aqua” – they are tablet form Tetracycline hydroperiodide. Each tablet contains 4mg of iodine. They are slow to dissolve and should be used up when the bottle has been opened.

Iodine crystals. It is possible to make your own iodine solution by the Kahn–Visscher method. This is done by putting 5g of iodine in a glass jar (about 30ml) with a paper lined Bakelite lid. The jar is filled with water. The saturated solution will disinfect about 2 liters of water but care must be taken not to draw up any crystals. A commercial version of this is Polar Pur.

e. Ultraviolet. Its worth noting that when harmful micro organisms are exposed to the ultraviolet light, their RNA /DNA is disrupted by absorbing the UV this makes the organism sterile and safe. UV is found commonly in “inline” systems for water drawn from wells and bore holes. It also has more “portable” variants – notably the “steri pen” battery powered UV water treatment system. Even leaving water in a clear bottle in strong sunlight will have a beneficial effect id done for a long enough period and in strong enough light. It should be noted though that any “cloudiness” in the water will render UV treatment ineffective so it is best combined with filtration.

3. Adsorption

a. Activated Charcoal. One very useful item in water purification is activated charcoal. Activated charcoal is not the stuff from your barbecue (although its chemically similar). It is charcoal that has been altered by a special manufacturing techniques to make it highly porous. So porous in fact that a gram of activated charcoal has a surface area of up to 2,000 square meters. Activated carbon adsorbs (chemically bonds with) certain chemicals as they pass through it thereby trapping them and removing them from the water. This is not true of all chemicals – some are trapped:

(1) Mercury, organic arsenic complexes, 245 T (dioxin) and chlorine. Its worth noting that chlorine is adsorbed – your carbon filter will remove the chemical taste from water but also prevent it being efficacious – always filter first and then chemically treat!

(2) Its worth noting that activated charcoal can trap and become a breeding ground for bacteria. Some contain other materials (such as silver) to inhibit such bacterial growth however it is a good idea to regularly flush your carbon filter with clean decontaminated water to remove bacteria.

(3) Activated charcoal is used in two forms – granular and block. Block both filters and adsorbs and is often seen as the superior product.

b. Resin Filters. Resin filters act on an ion exchange principle – they remove cations (e.g. lead and mercury) and anions (e.g. chlorides) with harmless ions such as hydroxyl (OH). Brita filters are a common example of ion exchange filters. Quality field use filters often combine activated charcoal with resin filters.

c. Distillation. Distillation is often thought to render all water safe. In effect water is heated to the point of evaporation and the steam gathered and condensed. The heating action will kill all micro organisms and many chemicals (with a lower boiling point than water) will be left behind and not come across in the distillate. It is a fuel heavy and mechanism to produce large quantities of fresh water although a variety of techniques (including the “solar still” and “connected bottles” will produce small quantities in extremis). It is worth noting that some chemicals (e.g. methanol) have a lower boiling point than water and can come across in distillation.

4. Practical Solutions: Having talked a lot of “theory” lets look at some practical solutions and discuss the pros and cons of each.

a. Perhaps the simplest of water filters is the “Milbank Bank or Base Camp Filter” – a tightly woven canvas bag often issued to British Forces Very similar to most camp size water filters systems sold in the US. This is how they work – The hanging hole is opposite the “toe” of the sock shaped design causing it to hang “toe down” and allow the water filtering through it to be received accurately into a receiving vessel. Although its normal to attach a simple cord to the bag, I use a carbiner so that I can tie the cord on, fill the bag from a stream and then quickly clip the bag in place (its heavy when full and you end up needing three hands to hang it. Before use its important to soak the bag to swell the fibers

Fill the bag - put it so the mouth faces up stream and let water do the work and clip it to a high point. What we have at this point is coarse filtered water. We have not removed any organisms. A good rolling boil will do the trick. Please note that a rolling boil is big, fat bubbles – not a few little ones. It would of course be fine to use chemical disinfection rather than boiling if this is your preference. Well its simple, effective, does not wear out with use. The disadvantages? It takes a little longer than other systems and provides no protection against chemical hazards. Due to the relative coarse filtration, some degree or turbidity may remain leaving a slightly gritty taste to the water.

b. Home based. For home based use or even base camping, the British Berkley is a gravity fed filter and contains some of the best filters made (ceramic, silver, activated charcoal and ion exchange resin). Up to 5 gallons can be poured in the top where gravity forces it through two or four filters to the bottom where it is literally “on tap” The advantages of this unit are its ease of operation, huge capacity and superior filters. Disadvantages are cost and the fact that it is not
effective against viruses so boiling is still advised if viruses are suspected. You can purchase the whole system for around $350.00 or buy 2 5 gallon buckets, 2 -4 Berkley filters, 1 bucket lid, and 1 self closing spout. If you need instruction on how to build one research it on the internet. These filters will last for about 10,000 gallons 2 years?.



NOTES:

1. 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.

2. Viruses can be spread by everything from urinating to brushing your teeth to spitting in a stream).

3. 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!

4. 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.

5. Iodine should not be stored in plastic but in glass bottles with paper lined Bakelite caps. Iodine can leach in plastic bottles. This clearly carries some risk of breakage and iodine is messy stuff!

[wac220]

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Good post with great information. Thanks for doing most of the research for us.

[RICHFL]

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This lesson is just the beginning of what to do about water. Beyond security this is the highest priority people need to have. You will start dieing when:

You have no air to breath starting in 4 minutes

You have no water to drink starting in 3 days

You have no food to eat starting in 30 days

You have no MTV to watch in 90 days!!! LOL

You have no FOX NEWS in 80 days. lol

You have no SEX ???? don't know haven't been there.... Most likely would shoot some thing.

[Applejack]

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this is a great post on water. We are getting a lot of our water needs taken care of such as the well, but for now what about a whole house filtration system? Does anyone have any ideas on this? right now we are on city water and if that get's cut off we have almost got our other ways in place. But would like to have plans for city water for as long as we will be able to use it. We filter our dranking water now with a filter on the refridg. but am thanking about whole house.
Aj

[RICHFL]

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YOU CAN BUILD WHAT IS CALLED A slow sand filter It is built around a long pipe that is filled in alternate levels of sand, pea gravel, charcoal, and again sand about 6 inches each level; it must lay at a 30 degree angle to the ground with the end capped to a hose to run to your water tank.

You let water run slowly down the pipe (minimum of 6 inches X 6 foot long) filled with the material I listed above. Even with this filter system you still need to pasteurize it for (160 degrees for 20 minutes). What I did was use the host to run into a solar still made up of black plastic made into a large self contained water container.

[myakka]

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Another good article RICH. There is a lot of debate on another forum I visit about the "drinkability" of rain water off of a roof catch system.

My opinion is that even rain water can be tainted, and birds poo on the roof, so I say filter and process EVERYTHING.

After all, if you ere on one side or the other, I pick the side that doesnt end in dysentery. (Especially in a world with limited medical access)

[Applejack]

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YOU CAN BUILD WHAT IS CALLED A slow sand filter It is built around a long pipe that is filled in alternate levels of sand, pea gravel, charcoal, and again sand about 6 inches each level; it must lay at a 30 degree angle to the ground with the end capped to a hose to run to your water tank.

You let water run slowly down the pipe (minimum of 6 inches X 6 foot long) filled with the material I listed above. Even with this filter system you still need to pasteurize it for (160 degrees for 20 minutes). What I did was use the host to run into a solar still made up of black plastic made into a large self contained water container.

Would this system work on city water? we are conected to the city water from the street. Or is there some type of filter that we can connect under the sinks to filter the water as we turn it on. This is not the well but the city water.
AJ

[RICHFL]

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During any disaster natural or man made one of the first things to go is the use of POWER. No lights, no heat, no A/C, no refrigerators, no freezers, and most of all NO WATER. Ask any one who has lived through a hurricane to tell you about it. Yea I've been thru a few down here in Florida. Once the power goes out it can take weeks or even months to get it back on. Ask New Orleans - they still have areas with no power after the disaster called Katerina! (5 years)

Most water systems move water through your pipes using high speed pumps. If you have your own well it is hooked up to draw water using an electrical pump. So with no power - no water.

No use of city sewer systems. They also use pumps to move the waste water to the waster water treatment facilities. You will find that out once your pipes start backing up with that waste water in your sinks, baths, toilets, etc. If you have your own sewer system you can continue to use it (Lucky you) Other wise you need to build , maintain, and use an outhouse like we did before the 1940's.