When I embarked upon this project my goal was to come up with a recommendation for easily purifying water, long-term, without electricity— and without spending much money.
I assumed that since I’m an electrical engineer who easily “aced” chemistry in high school and college that I’d have the research done and the post written in under an hour.
I was so very wrong, however.
I’ve spent, literally, hundreds of hours poring over information from the CDC, WHO, various other government agencies, leading universities, research hospitals and manufacturers and pulled together enough information to easily write a 100 page book.
A book that no one would read.
The things that struck me most were:
1) it can be incredibly complex to produce perfectly clean water
2) I’m amazed at how much drinking water we waste.
You know you live in a nation of excess when most people water their yards with drinking water while, around the world, 3 children die every minute from impure drinking water.
I will never look at water the same way again.
I have done my best to reduce this article down to the barest amount of information and, at the end, I will tell you how I would easily and cheaply produce pure drinking water, long-term, should I ever need to.
“But Chelle— all I have to do is turn on the faucet and I can get all the pure water I want.”
Well, you obviously can’t take that faucet with you when you go camping— and if you’re ever the victim of a natural disaster like hurricane Katrina or hurricane Sandy you’ll be glad you read this article when the water coming out of the faucet is no longer safe to drink.
“I’ve heard that if you boil water it will always be safe to drink.”
That’s what I thought, too, but it’s not even close to being correct.
Boiling is a great STEP in the water purification process, but you won’t always have the resources to do so— and you’ll still have to do a few more things to make the water safe to drink. I’ll cover all that here, though.
So here’s the part where I have to post a disclaimer so that no one sues me and takes away my beloved 12 year old minivan:
I’m not an expert and do not represent myself to be an expert. Even though I’m smart, I don’t know everything. If you don’t believe me you can ask my spouse. Despite pulling this information from reliable and authoritative websites you should assume that by following my advice you could become ill, die, spontaneously combust— or worse. You should always do your own research before undertaking any activity that could impact your health. The procedure given, here, is merely the procedure that my family and I will follow in an emergency situation. If we die it will be solely my fault.
Now that the fun part is over, let’s begin by talking about all the stuff you might find in your water and what methods you can use to remove them. I’ve reduced categories that could each be its own chapter in a book all the way down to bullet points. If you want to know more I would encourage you to Google each heading and learn more:
Bacteria: boiling, chemical, microfiltration
Viruses: boiling, chemical, nanofiltration (although ultrafiltration can be reasonably effective)
Protozoa: boiling, microfiltration
Chemicals (i.e., herbicides, pesticides, etc.): activated carbon, nanofiltration
Suspended Solids: microfiltration, floc
Heavy Metals: activated carbon, distillation
Nitrates: ion exchange
The above list is thorough but not exhaustive. If you think of something that you feel strongly about me including in the list then please feel free to send me a note and I’ll include it.
You probably noticed that there’s no “one thing” that gets rid of everything— which means that you need to use a multi-step process.
“What about reverse osmosis? If you’re such a chemistry hot shot you should have known that it will take care of pretty much everything. In fact, it will even turn salt water into fresh water. So why didn’t you mention that, huh, Chelle?”
Of course you’re correct. Reverse osmosis is the closest you can come to a one-step process that will produce pure drinking water (with a few small exceptions).
The reason I’m not including it is because most systems require electricity to operate, due to the high pressures required, and the membranes become clogged with impurities pretty quickly. If you were lucky enough to find a system that operated with a hand pump it would only work for a limited time unless you had plenty of replacement membranes.
Since it didn’t meet my criteria of “cheap, no electricity and long-term” I don’t consider it to be a viable solution in a long-term emergency or survival situation. If you get hold of a hand pumped reverse osmosis kit you should, by all means, use it as the final step in water purification. That will enable the membrane to have the longest life.
Boiling is a great way to kill anything that’s living in the water— especially protozoa, which include Giardia lamblia and Cryptosporidium, the two parasites most likely to give you diarrhea if you drink “bad” water.
Unfortunately, boiling does NOT remove anything that’s dissolved in the water— like heavy metals, pesticides, etc. And it doesn’t clarify the water. That means that if you boil swamp water, it’s still going to look like swamp water after you’re done.
If you boil water for 5 minutes you should pretty much kill anything that’s living in the water, with the possible exception of botulism spores. If you have reason to believe that they’re in the water, as well (not terribly common), you must boil the water at 240 degrees— which would only be achievable in a pressure cooker.
There are a dizzying number of filtration systems on the market for every conceivable application. I won’t bore you with the numbers (you can Google them, if you wish) but microfiltration systems have larger pores than ultrafiltration systems which have larger pores than nanofiltration systems.
Microfiltration is very effective for most contaminants but will not remove viruses. Viruses can be easily killed in other ways, however, and I will use microfiltration in conjunction with other methods to purify my water since microfiltration systems are the most readily available.
Filtration systems that use disposable cartridges are not acceptable, in my opinion, since they will eventually clog and have to be replaced. In a long-term situation this will not be practicable. For that reason, I feel that a cleanable ceramic filter cartridge is the best way to filter drinking water.
Ideally, a ceramic filter will be impregnated with silver so that it will prevent bacteria from colonizing in it.
Chlorine and Iodine are both excellent sanitizer/oxidizers and accomplish nearly everything that boiling accomplishes— with one notable exception. Protozoa envelop themselves in a protective cyst when they encounter harsh environments. This cyst is sufficient to protect them from chemical sanitation. The good news is that microfiltration easily removes protozoa, so chemical sanitation will be one of the steps I use to purify water in an emergency.
While unscented bleach is perfectly acceptable for sanitizing water, it has a limited shelf life before it starts losing its strength. So if you wish to sanitize with chlorine you should use a granulated chlorine like calcium hypochlorite.
Iodine is often used by backpackers, but many people are sensitive to iodine— and the metallic taste it imparts upon the water is awful.
Fortunately, once iodine has done its job you can easily neutralize it— and get rid of the bad taste— by adding ascorbic acid (vitamin C). If you left your vitamin C tablets at home you can simply add a powdered drink mix that includes it.
The U.S. Department of Agriculture’s Forestry Service says that vitamin C can also be used to eliminate excess chlorine, as well.
There are a number of UV “pens” on the market that perform largely the same functions as boiling— including the killing of protozoa.
Some even use AA batteries— which means you can easily recharge them with a solar panel.
The reason I’m not recommending them, however, is because I found an uncomfortably large number of dissatisfied customers who relied solely upon their UV pen for sterilizing their water and were left hanging because it malfunctioned.
If someone comes out with a very reliable UV pen that uses rechargeable batteries then this could be an excellent option for killing bacteria, viruses and protozoa.
Coagulation and Flocculation:
Eeeeeewww!!! That sounds gross! But it’s actually really cool— and you’ll definitively want to use this to clarify your water.
Floccing consists of adding something to the water that causes all the little floaty things to come stick to it until it becomes large enough to float to the bottom.
It will turn dirty, swamp water into clear water and, besides removing those visible suspended solids, is even partially effective against bacteria, viruses, protozoa and heavy metals.
In a dire emergency you could possibly get by with just floccing and chemically sanitizing your water. (Steps 1-3, below.) While it’s not the perfect solution, it will drastically improve otherwise impure water.
The Centers for Disease Control worked with Procter and Gamble to come up with sachets that are distributed to third world countries that do nothing more than floc and chemically sanitize.
The reported cases of diarrhea— the most frequent cause of death since it severely dehydrates the victim— dropped drastically. You can read about it here.
“Where the heck would I buy flocculent? And is it expensive?”
It is EXTREMELY easy to buy! The two most common ones are aluminum sulfate (also called “alum”) and ferrous sulfate.
Alum can be purchased in the spice aisle of the grocery store, since it’s used for pickling and cooking— but it’s a little pricey, there. You should head to your local feed and seed or gardening supply store and buy a big 10 pound bag for next to nothing.
If you prefer to use ferrous sulfate you can buy that at any pharmacy or Walmart. It’s used as an iron supplement. Be sure to read the labels because you don’t want to buy the stuff that says, “65 mg which is the equivalent of…” That’s elemental iron. You want ferrous sulfate. It will just say “325 mg Ferrous Sulfate.” THAT’S the stuff that will floc your water for you.
If you make charcoal in a certain way you’ll end up with activated carbon— which is WAY more absorbent than regular charcoal.
In fact, activated carbon is one of the most absorbent materials known to man.
If you run water through activated carbon you’ll be able to get rid of most of what’s dissolved in the water— those chemicals and heavy metals that you couldn’t filter or sanitize out. The longer the water stays in contact with the carbon the more stuff it will remove. We’ll be using this.
Distillation is a great way to purify water. It doesn’t get rid of everything— but it comes pretty durn close. I’m not going to use it in my treatment process because the faster methods require heat— but if you want to Google it and learn about things like solar distillation I would certainly encourage that.
Distillation is an excellent emergency technique for gathering water and you can supply yourself with enough to survive on with little more than a tarp cut into two pieces.
If you were going to do further reading I would probably suggest this, above anything else.
Ion exchange is an excellent way to purify water— but I it’s not really practical in a survival setting. You might wish to read up on it just to be sure.
“But Chelle, how am I supposed to get rid of nitrates in the water?”
Nitrates are only dangerous to infants under the age of 6 months and to animals. Their digestive systems convert nitrates to nitrites.
Nitrites are bad because they attach themselves to the hemoglobin in your red blood cells in the same place where oxygen is supposed to attach. As a result, high levels of nitrites can cause “blue baby syndrome” which is oftentimes fatal. Babies and animals can, literally, suffocate.
Once a human passes the age of 6 months their bodies no longer convert nitrates to nitrites. Instead, the nitrates are simply absorbed and subsequently excreted.
Nitrates usually end up in drinking water from fertilizer run-off. If you live in an agricultural community where lots of fertilizers are used then you should be aware of this potential safety hazard.
Obviously, you would not want to get your drinking water from a golf course or similarly heavily fertilized area.
Ozone is an excellent sterilization technique but all the methods I’m aware of require electricity which did not meet the criteria I set for my survival water purification process.
That’s as much background information as I’m going to provide, here. Now it’s time to get specific as to how I would easily and inexpensively purify water, over a long period of time, without electricity:
Here’s the shopping list (Items should purchased BEFORE a disaster strikes and stored in one’s home or with one’s camping kit):
1) Four 5 gallon plastic buckets
2) Aluminum sulfate (Alum) or ferrous sulfate (from Walmart, the drug store, grocery or garden supply)
3) A few 1 pound bags of calcium hypochlorite (pool shock— from Walmart or your local pool supply)
4) Pool water test strips that measure chlorine and pH.
5) A bag of activated carbon (used for fish tanks, so head to your local dollar store or pet supply)
6) A 2 liter soda bottle
7) A woman’s trouser sock or pantyhose.
8) This ceramic microfilter. It’s the cheapest one I can find that appears to be reputable.
Everything on that list can be purchased for a total of approximately $75 and will provide you with a couple of years worth of clean, pure water.
Time to get to work:
I would start by finding the best water available. Running water is better than still water and ground water is better than running water. That’s your starting point.
Pre-filter your water into 5 gallon bucket #1 by pouring it through a cotton tee shirt, bandana or coffee filter. That will get rid of the big stuff.
Add either aluminum sulfate (alum) or ferrous sulfate to the water, stir vigorously for not less than 30 and not more than 60 seconds, and wait for it to clear.
The trick is to add enough— without adding too much. The dirtier the water is, the more floccing agent you’ll need.
If you add too much you won’t really hurt anything, because the activated carbon will remove the excess aluminum or iron, but you want it to last as long as possible— so try to get it dialed in as close as possible.
So how do you know when you’ve added the right amount?
We’ll find out in step three.
Carefully pour or siphon the clear water into 5 gallon bucket #2, making sure you leave all the floc behind in the bottom of bucket #1.
[Note: If this is the first time you’re purifying water from this source, repeat step 2 to see if you produce any more floc and proceed back to this point, pouring the clear(er) water off, each time. Once you end up with clear water, add up the total amount of alum or ferrous sulfate you used and use that entire amount, all at once, in future batches. Once the water looks nice and clear (or as clear as you can get it) you should complete the rest of this five step procedure. If you’re having trouble producing floc you should try adding some baking soda. The reasons for doing so are complicated— so you’ll just have to take my word for it.]
Add enough calcium hypochlorite to bring the free chlorine level to between 3 and 5 ppm (parts per million). Use the pool test strips to verify this.
If the test strips happen to show that the pH is way low or way high you should tweak the water with some lemon juice or vinegar to lower it, or baking soda to raise it. Chlorine works best when the pH is near 7.
Allow the chlorine to work for at least 30 minutes. If you want to double that, so much the better.
If, at the end of the 30-60 minutes, the strips show that there’s no more chlorine in the water then that means that it all got used up in the sanitation process and you need to add more calcium hypochlorite to repeat the process. This will be a very rare occurrence, but it’s something you should know about.
You want there to be residual chlorine so that you know all the creepy crawlies have been killed and there was still a little chlorine left over.
Connect bucket Nos. 3 and 4 together using the microfilter that you purchased, above. There are instructions in the box, as well as a video available on the website.
Any bozo can do it in 10 minutes— although I would suggest doing this BEFORE disaster strikes.
Here is a pic that I snagged from AdvancedSurvivalGuide.com:
If you follow the directions you’ll end up with two 5 gallon buckets stacked on top of each other with your handy dandy $30 ceramic microfilter as the only path between the two.
The kit also includes a spigot that you can install in the bottom bucket to make it easier to get the clean water out.
But we’re not quite done, yet.
Cut the bottom off of a 2 liter soda bottle (the big end) and place a pantyhose leg or trouser sock in it in the same way that you’d put a bag in the kitchen trash can.
Fill the sock with activated carbon, drill a small hole in the cap of the soda bottle— and you’re ready to go.
Run water through until it looks clear, since new activated charcoal can have carbon dust in it.
The reason we’re using the cap with a small hole drilled in it instead of just letting it run through, quickly, is because we want the water to spend as much time in the activated charcoal as possible.
Don’t run the water through the carbon filter until you’re ready to drink it.
Because the activated carbon removes all the chlorine— which means that any new bacteria that happened to get into the water would be able to thrive.
I know that these five steps might sound a little overwhelming, but once you do it a few times it will be a piece of cake.
If your life is at stake you’ll be glad you have this knowledge.
Remember— do your own research. This is only how I would purify my water. It might not be the best way for YOU to purify YOUR water.
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