# build a water filter



## SodaPopinski

is this possible and how can I make a filter like this using sand and random junk?


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## cannon

You could get some cans, make one into a fire container, throw random junk it, make a holder for the other can put it above that one, boil water in it, use random junk to make the fire sparks, useful litter is almost _everywhere_ assuming you can come up with something flamable enough you can purify it by boiling it then devise a particle filtration system using paper of various sorts with holes punched in it and rotated so the holes dont line up


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## landshark

Good question, I don't know what sand would filter out, there has to be something that absorbs toxins that combined with purified sand and other things can do a semi-good job of it. 

Anyone know if there is a way to filter out salt from salt water?


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## Jerseyzuks

landshark said:


> Anyone know if there is a way to filter out salt from salt water?


You can't really "filter" the salt out, because it is not a particle, it is disolved in the water.

Salt water can be turned into fresh water by desalination. Salt water is boiled, turned into steam, the salt remains behind, and the steam is collected and condensed back into fresh water.

On a small scale, if you had a teapot full of salt water, and held a mirror up infront of the steam, the condensation that collected on the mirror and eventually began to drip off would be fresh water.


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## JeepHammer

There are two ways to remove the 'Salt' from 'Salt Water',
1. Chemical Filters.
There are many different brands of 'Survival Pumps' that use chemical filters and membranes to remove most of the bad things out of salt water.

They are often found anyplace Coast Guard approved Lift Boat supplies are sold.

2. Distilling.
Distilling can be done a number of ways, and you usually see the 'Cooker' or 'Pot' with a fire under it and a coiled tube on top to condense the water vapor back into liquid water.


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## spikegomez

Filtering the salt in water is not as easy like filtering the particles in water... it may be possible on distilling the water... water filter can't trap the salt... it is a soluble compound... 
___________________
Refrigerator Water Filters


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## jams002

it is not that easy to filter a water came from to faucet some water have mix an salt and other substance,


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## EvilTOJ

Jams, you're not making any sense at all.


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## filterdix

Yeah Filtering the salt in water is not as easy like filtering the particles in water... water filter can't trap the salt...


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## girishanthan

SodaPopinski said:


> is this possible and how can I make a filter like this using sand and random junk?


Step to create Simple water filter

1. To start with, you need a container. If you can find a large, empty can, use it. Punch 5-10 holes in the bottom of the can. A large plastic bottle is also fine. Cut the end of the bottle off evenly. If there is no container available, you have to use what material that nature can provide, or that you brought with you.

If you find a birch tree, make a cone of birch bark. The cone will need to have a fairly small hole in the bottom. Tie the cone with rope to keep it from opening up. Put a few stones in the bottom to help hold the filtering materials in place.

2. Fill your container with layers of sand and gravel from the bottom to the top. For sand and gravel, use both fine and coarse layers. The bigger the filter and the more layers you have in it, the better.

If you use a bottle or cone, you need to stop the sand to get out of the container. Find some filter material you can place at the bottom. For instance:
· a couple of inches (centimeters) of pebbles.
· a grass mesh, make sure it's nonpoisonous grass.
· or cotton material.

3. Collect some water. Pour your collected water through the filter. Catch it in another container at the bottom. Look at the water that comes out of the filter. It should be clear. If not, you may have to pass the water through the filter more than once.

Safe water

Now you know how to make a water filter, but to get safe water to drink, you also have to purify your water. The water may still contain harmful bacteria that your filter did not remove.

To improve your water filter, replace the sand and gravel with a layer of charcoal. Keep the top layer of sand or gravel. Get charcoal from your fire, crush it, not to powder but just fine gravelsize.
:2thumb:


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## NaeKid

I have fish in a tank in my house. I have wondered a few times if I could use fish-tank filtration material to create drinking water and if I can - what would be the best way to make the water drinkable?

Has anyone done this and if so, how has it been done? Pictures would be wonderful!


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## Expeditioner

NaeKid said:


> I have fish in a tank in my house. I have wondered a few times if I could use fish-tank filtration material to create drinking water and if I can - what would be the best way to make the water drinkable?
> 
> Has anyone done this and if so, how has it been done? Pictures would be wonderful!


Interesting idea NaeKid! The mfg of the filtartion material might be able to provide you with some technical daat that would answer your question.


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## Fn/Form

I don't have the links handy, but there are third-world self-help guides that have plans for water purification. World Health Order, Doctors Without Borders, etc. may be a start.


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## xj35s

*Small distiller?*

I have been thinking. the only way to make dirty water into 100% pure H2O Is to boil it, collect the steam, and condense it back to water.

Now. Why can't we do this with a small can and a funnel cover with a coil of copper tubing on top?

I'm going to build a small portable one and test it with some dense salt water and some smelly swamp water. It'll be interesting to see what get's left behind.


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## xj35s

*better than filtration...*

Needs the sun but totally pure water...

Solar Water Distillation


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## rkba01

1. Slow sand filter

Biosandfilter.org - The Bio-Sand Filter










2. pool shock!

Better than Bleach: Use Calcium Hypochlorite to Disinfect Water


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## rkba01

Also, you *can* filter the salt molecules out of saltwater. For this you need a highly specialized filter (called a membrane), one with sub-microscopic little holes (called pores). These things are not cheap (unless you do research in this topic, in that case they'll send you whatever you want) and are typically spiraled 'on the roll' or hundreds of little tubes packed in a larger rigid plastic tube.

This type of filtration is called Reverse Osmosis (RO). It is called such because you need to overcome the osmotic pressure in order to push the water molecules through the pores.

You will end up with two streams of water. One is a concentrated stream of water that contains most (like 80%) of the salts (called retentate), the other is a stream of water with a lesser concentration of salt (called permeate).










Show above is a 'crossflow' type, one that typically fouls less (pores get plugged over time). And just like in the sandbed filter you can apply a backflow to flush out some of the pores. But eventually the filter becomes irreversibly clogged.


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## janjakk

we are actaully making now a built in solar water filtration..we still workin on it, i think this gonna be effective..


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## Safari 7

*Sand, charcoal*

It takes a LOT of sand to make a good filter, even just for particulates. You'd be looking at a column anywhere from 15 feet to a hundred feet high depending on the nature of the sand (size and shape of the grains is critical). Best readily available material is charcoal, and charcoal is extremely variable. Hardwood charcoal is generally best, and the VERY best is charcoal from coconut shells (the inner shell, not the husk), aka "activated charcoal".

But as has been pointed out, nothing short of reverse osmosis or distillation is going to "filter" out salt or anything else that is in solution rather than suspended particles.

I'm pretty fond of the expen$ive (~$200) Sawyer Complete Water Purifier System - not only does it flaunt a million gallon guarantee, it filters down to 0.02 microns absolute, which removes even viruses. And no work involved since it runs on gravity flow...


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## jamesd

There has to be some kind of membrane that removes salt. Does an RO filter remove salt?


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## jamesd

jams002 said:


> it is not that easy to filter a water came from to faucet some water have mix an salt and other substance,
> 
> You're serioudly not making sense mate!
> 
> _________________


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## bunkerbob

jamesd said:


> There has to be some kind of membrane that removes salt. Does an RO filter remove salt?


RO does remove salt, its membrane will remove just about everthing, the battery manufacturers even said it is pure enough for battery water. I have one that makes water for my off-grid batteries.
Some of the largest fresh water plants, in the Middle east, use RO to make fresh water from sea water. Desalination - Wikipedia, the free encyclopedia Californis will be building some soon Dry California OKs huge desalination plant - Environment- msnbc.com


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## abmish384

hello jeephammer 
good description.
thnx


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## walsh12

I think some water filters can filter salt from water.

You might have to search a little hard.


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## buygreen111

Hi,
Really its a nice idea to make water filter. Definitely I will try my best to build a water filter for me. A water filter provides clean, healthy water for cooking, as well as drinking, at the convenience of tap water. Also Water filters provide better tasting and better smelling drinking water by removing chlorine and bacterial contaminants. you can also buy good quality of water filter from market with an affordable price.


Thanks.


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## booter

I have built my own, made from sealable food-grade plastic containers connected 'in-series' with clear vinyl/plastic tubing, [in-flow from top in to, out-flow out the bottom of each filter container], aquarium supplies are great for buying filter media. Most fish are extremely sensitive to irregularities in their water, they sell; superfine media bags, activated charcoal, also resin matrix 'chemical scrubbers' which remove harmful chemicals/metals, suspended in the water. Start with a 'pre-filter' to separate all the particulate you can see, [I use a stainless steel drain basket with a large commercial-size paper/fiber coffee maker filter], these are available at restaurant supply stores. My filter containers have holes drilled for the in-flow & out-flow hoses, sealed with clear silicone bathtub caulking, the lids all lock down with silicone gaskets for sealing. On the first in-series container, I have mounted an air fitting compatible with a small hand-held bicycle pump in order to pressurize the containers to get the water flowing form one filter container to the next in line. Everything fits inside a 'RUBBERMAID ROUGHNECK' 18gallon storage container, making it completely portable. I finish my water with my SteriPEN, just to be safe.


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## Emerald

A friend just gave me this link to making a bio-sand filter that is commonly used in third world countries to clean water.
Bio-sand filter
You do have to download the file but it has pictures and is really worth giving a good look. Most parts that are used are easily available now and it might be worth getting the parts to make one now and just have it available. It is something that the hubby and I have talked about and thought about getting all the parts and the Rubbermaid tub and just store it till needed.


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## gitnready4it

Excellent post. I'm gonna try this one soon. Thanks for the info!


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## Nadja

I would suggest that everyone save this one to their computer. It is well worth having this info later on if not already.


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## scoob

howdy yall, i like this subject. im planning on building a biosand/slowsand filter. ive done quite a bit of research and aside from berkey and sawyer, which are not very cheap, not unaffordable, but not cheap, the biosand is my personal choice for purification. and its realitively affordable as well as not too difficult to make. it takes some time to get going, but once the beneficial bacteria get established in the very top layer of the sand it is supposed to filter out most if not all voc's (volitile organic compounds). please do your own research and dont take what im saying as absolute truth, i am by no means an expert. i just studied untill i was satisfied as to which rout i would follow. just my 2 pennies. good luck and be safe!


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## Highwater

scoob said:


> howdy yall, i like this subject. im planning on building a biosand/slowsand filter. ive done quite a bit of research and aside from berkey and sawyer, which are not very cheap, not unaffordable, but not cheap, the biosand is my personal choice for purification. and its realitively affordable as well as not too difficult to make. it takes some time to get going, but once the beneficial bacteria get established in the very top layer of the sand it is supposed to filter out most if not all voc's (volitile organic compounds). please do your own research and dont take what im saying as absolute truth, i am by no means an expert. i just studied untill i was satisfied as to which rout i would follow. just my 2 pennies. good luck and be safe!


VOC's are an interesting group of contaminants and include some pretty nasty ones. They vaporize at a low temperature and usually give off a strong odor. They can give water a sweet taste, too. They include gasoline, benzene, paints and solvents. If you have any VOC's in your water source, you will want to use activated carbon to remove it. Granulated Activated Carbon will reduce the VOC's as well.

As far as Berkey's and Sawyer products, Berkey's do remove VOC's. I don't believe Sawyer claims to remove them. I've seen others claim they do, but Sawyer doesn't state this on their website.


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## Zonation

Why build it when you can buy it.


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## LincTex

Emerald said:


> Bio-sand filter
> You do have to download the file but it has pictures and is really worth giving a good look.


If anyone can not download this, please PM me with your email address and I will attach it to an email for you. It is less than 1Mb



Emerald said:


> Most parts that are used are easily available now and it might be worth getting the parts to make one now and just have it available.


Absolutely. I have enough "parts" to make three... but not enough sand. Sand is easy to find but hard to move. I don't have a lot of room to store spare sand right now. Maybe I can make a HUGE sandbox for the kids? That will be my reserve!


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## Garand69

SodaPopinski said:


> is this possible and how can I make a filter like this using sand and random junk?


It is possible, but depending on scale all you are making is a strainer.

DIY filters are very possible and can be done on the cheap, but first ask your self what this filter is for? Do you want the knowledge to survive a "stranded in the middle of nowhere" situation by yourself, or are you seeking the info for a long-term water solution for a family of 6.

The Bio-Sand type of filter has some great qualities as well as some draw backs. In a "survival" situation, the materials are probably lying around for you to build one, but you have to remember the causes of surface water contamination, most of them come from run off over the sand and gravel you are going to use to make the filter.

Planing for a long-term situation, hopefully prior to the situation :gaah: , gives you some time to do your research and find some decent quality materials to make a first rate filter. It also gives you the ability to improve on the Bio-Sand filter by adding two additional types of filtering media, Activated Charcoal and Dichotomous Earth. Those additions take the Bio-Sand filter up a notch or two.

The big draw back after you get over the "quality" of filtering media being used with the Bio-Sand is that you have to keep it running in order for the "Bio" portion of the filter to work (much like the Bio-Wheel fish tank filter). Once it drys out and the "Bio" dies off, it will take a fair amount of use to reactivate the bio function. The "Improved Bio-sand" design that keeps the filtering media wet by raising the exit point for the filtered water works, but not on an extreme long term situation, because just like any standing water, it will get nasty.

If you add a layer of Activated Charcoal (for flavor) followed by a layer of Dichotomous Earth (for critters) as the last 2 layers, you will drastically improve the effectiveness of your filter, and it will work even if you just dragged it out of the closet for the first time, or if you have run it daily for months.

A Building Supply company that caters to Mason's will have the sand and Pea Gravel you need. Fine Sand aka "Mason's sand" and Coarse Sand aka "Torpedo" or "Play sand". The reason you go to a place like this rather than buy a bag of sand is simple, when you walk in to the office and ask to fill a couple of buckets of sand, they usually let you go for free. They sell the stuff by the ton, not by the pound, and their scales are usually in 20lb increments.

When you decide on a container to hold your media, consider length as being more important than diameter. A five gallon bucket with say 15 lbs of media properly layered will filter less contamination and critters out than a 4" diameter pipe that is long enough to hold the same 15 lbs of properly layered media.

Will this filter out chemicals and salt? Don't count on it, but it will get out the beasties that will make you very sick and most of the chemicals. The Bio-Sand Filter on it's own is not that remarkable, it only reduces water caused diarrhea by 50% ish, but it certainly is a good start.

Here is a good video.... I would add the layers of Activated Charcoal and Dichotomous Earth between the Pea gravel and sand using an extra end cap with holes drilled like the "diffuser plate" and then a coffee filter on top of that to prevent the finer Dichotomous Earth to infiltrate the pea gravel.






The Big Berkey is nice but pricey, but you can duplicate it for much less using the same filters in a DIY bucket set up.

DIY Berkey Filter


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## LincTex

Garand69 said:


> .I would add the layers of Activated Charcoal and Dichotomous Earth between the Pea gravel and sand using an extra end cap with holes drilled like the "diffuser plate" and then a coffee filter on top of that to prevent the finer Dichotomous Earth to infiltrate the pea gravel.


I would avoid doing that.... keep it simple (KISS principle)

The final product that comes out can have the last few (if any) pathogens killed with a little bleach. You can pour the water back and forth between two buckets to get the bleach out.

Nothing takes salt out, except for distillation.


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## Garand69

LincTex said:


> I would avoid doing that.... keep it simple (KISS principle)
> 
> The final product that comes out can have the last few (if any) pathogens killed with a little bleach. You can pour the water back and forth between two buckets to get the bleach out.
> 
> Nothing takes salt out, except for distillation.


Can't disagree with the KISS concept! But that is why I would add those two items to the filter.

1st it makes it ready to use right off the bat and you do not have to wait until the Bio Flora is developed in order to consider the water safe to drink, and you do not have to maintain that Bio Flora through regular use.

2nd, adding a second step using bleach while simple, does add more steps to the process.

It all boils down to the situation at hand and whether or not you have the time and materials to get it done. If you are improvising this filter Post SHTF you may not have any options in filtering media, but in the good times, there is no reason not to improve on an idea.


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## Londoner

I was a water engineer in a previous life. I wouldn't advise it because you have no way of knowing its working except the hard way.

The only way is to invest in a proper Bio system. without a lab you do not know what is in the water. Sand etc may filter out solids but why bother, you can buy a 5 micron water filter for about 5 dollars. But it won't filter out the bacteria and viruses, neither will charcoal

Its the biological contamination you need to fear and there are things out there that could definitely kill you if sewage gets into the water supply.Even if it doesn't kill you directly it will be horrible and render you so debilitated you will most likely die of the side effects.

But you probably only have one source of water so you cannot take chances. The only way to be sure about water is to boil it and thats a good 10-15 minute hard boiling. Buy a woodburning kettle. 

It depends where you are, if you are halfway up a mountain you should be reasonably safe. In general though I don't think the risk is worth it.


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## Londoner

24 hours after previous post

There is a thing called the Ribena test. Ribena is a blackcurrent cordial sold in britain . Mix up a quart then put it through the filter. Chances are it comes through blackcurrent colour and blackcurrent flavour.

Then substitute the word Ribena for the word Poop and you start to see the problem


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## LincTex

There is no need to shoot the wounded.

First, the blackberry currant isn't a good test, because a biosand filter needs a few weeks to build the "Schmutzdecke" http://en.wikipedia.org/wiki/Schmutzdecke

Doing that would kill the Schmutzdecke, making the filter useless.

You can kill the poop "fecal coliforms" by bleaching the water several days before needing it and letting the chlorine evaporate out (so it also does not kill the Schmutzdecke)

This should supply you with sterile and clean water, which can then be run through activated carbon to remove any petrochemicals.


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## LincTex

I should also add that there should be multiple ways for you to clean your water. A Berkey is a GREAT tool... but please don't dump swamp water into it, even though you could. Feed it with the cleanest water you can, so the filter "candles" stay cleaner for a longer period of time.

The BioSand is a great tool to get you to the point where the water is pretty good quality. You can add a little bleach afterward to kill pathogens, then aerate for a while to let the chlorine gas out. You could even run this water through a PUR or BRITA filter before the Berkey if you wish, but there are many ways to clean your water properly.


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## readytogo

In my opinion the days of building a water filter are over with ,so many filters out there to chose from I don`t see the need to go to all that trouble , but if the need comes up, you will definitely need active charcoal and ways to boil the water to finish its purification or by adding chemicals to it, pure clean water is very hard to find in the modern world today and a good desalting filter will cost around $2000.00 for a small hand operated one
http://en.wikipedia.org/wiki/Activated_carbon
http://www.htiwater.com/divisions/personal_hydration/index.html


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## Ryan_Johnson

www.en.wikipedia.org/wiki/Water_filter

If you do a little bit of simple research, you may come up with the answer that I got in approximately 45 seconds. Multiple-barrier filtration is the standard. Using not only activated carbon filtration, but particulate filtration to remove minerals, as well as something with specific porosity.


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## Ryan_Johnson

readytogo said:


> In my opinion the days of building a water filter are over with ,so many filters out there to chose from I don`t see the need to go to all that trouble , but if the need comes up, you will definitely need active charcoal and ways to boil the water to finish its purification or by adding chemicals to it, pure clean water is very hard to find in the modern world today and a good desalting filter will cost around $2000.00 for a small hand operated one
> http://en.wikipedia.org/wiki/Activated_carbon
> http://www.htiwater.com/divisions/personal_hydration/index.html


Good job linking. However, I found there is a more general listing on Wikipedia. 
On another topic;
This site needs some cleaning up/moderation bigtime. So many useless forum posts, so little information. It is highly disturbing. It must be someones idea of a funny science project to see how silly we all are when it comes to sharing purdinent information.


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## camo2460

Ryan_Johnson said:


> Good job linking. However, I found there is a more general listing on Wikipedia.
> On another topic;
> This site needs some cleaning up/moderation bigtime. So many useless forum posts, so little information. It is highly disturbing. It must be someones idea of a funny science project to see how silly we all are when it comes to sharing purdinent information.


Thank you Kalial Grabron your added wisdom and knowledge are very useful.


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## readytogo

Ryan_Johnson said:


> Good job linking. However, I found there is a more general listing on Wikipedia.
> On another topic;
> This site needs some cleaning up/moderation bigtime. So many useless forum posts, so little information. It is highly disturbing. It must be someones idea of a funny science project to see how silly we all are when it comes to sharing purdinent information.


I do apologize for disturbing your powerful knowledge base; I was just trying to help.


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## LincTex

readytogo said:


> In my opinion the days of building a water filter are over with ,so many filters out there to chose from I don`t see the need to go to all that trouble ,


It's about sustainability, dude!!!!!
When the supply of _"so many filters to choose from"_ dries up.... the *only* practical solution after that is to build one. (which is an eventuality anyway, since *all* water filters have a finite life)

Besides, the "filters to choose from" category also seems to equate to a lot of $$$$... so I'll pass.

I do have Berkey "Candles" to make the "double 5-gallon bucket" style of filter, but I still plan to feed water in that is the cleanest and most pathogen free that I can.

http://www.preparedsociety.com/forum/f20/dyi-berky-water-filter-19274/

http://www.saveourskills.com/gravity-fed-home-water-filtration-system

http://www.tacticalintelligence.net/blog/how-to-make-a-homemade-water-filter.htm


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## readytogo

LincTex said:


> It's about sustainability, dude!!!!!
> When the supply of _"so many filters to choose from"_ dries up.... the *only* practical solution after that is to build one. (which is an eventuality anyway, since *all* water filters have a finite life)
> 
> Besides, the "filters to choose from" category also seems to equate to a lot of $$$$... so I'll pass.
> 
> I do have Berkey "Candles" to make the "double 5-gallon bucket" style of filter, but I still plan to feed water in that is the cleanest and most pathogen free that I can.
> 
> http://www.preparedsociety.com/forum/f20/dyi-berky-water-filter-19274/
> 
> http://www.saveourskills.com/gravity-fed-home-water-filtration-system
> 
> http://www.tacticalintelligence.net/blog/how-to-make-a-homemade-water-filter.htm


I`m fully aware about survival and sustainability in the coming doom but dear fellow a mud filter will not help you at all in any scenario if you don`t have any way to purified the water ,the modern world of today as we speak has many good filters that take care the problem of building one, you can build one and try it at the nearest water pond but I pry for your health and the others that try the water. Good luck.


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## readytogo

*Disinfecting drinking water*

7 Steps to Emergency Disinfection of Drinking Water

Step 1: 
Filter murky or colored water through clean cloths or allow it to settle. It is better to both settle
and filter. 
Step 2: 
Boiling is the surest method to make water safe to drink and kill disease-causing microorganisms like Giardia lamblia and Cryptosporidium, which are frequently found in rivers and lakes. 
Step 3: To improve the flat taste of boiled water, aerate it by pouring it back and forth from one container to another and allow it to stand for a few hours, or add a pinch of salt for each quart or liter of water boiled. 
Step 4: 
When boiling is not practical, certain chemicals will kill most harmful or disease-causing organisms. Chlorine (in the form of unscented bleach) and iodine are the two chemicals commonly used to treat water. 
Step 5: 
You can use a non-scented, household chlorine bleach that contains a chlorine compound to disinfect water. (Remember, 1/8 teaspoon and 8 drops are about the same quantity.) 
Step 6: 
You can use tincture of iodine to disinfect filtered and settled water. Common household iodine from the medicine chest or first aid kit may be used to disinfect water. 
Step 7: 
Tincture of iodine. For cloudy water add ten drops and let the solution stand for at least 30 minutes.


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## undumb

I've seen survival filter instructions online and in manuals that use three handkerchiefs with grass, sand and charcoal. I have a few concerns and questions that aren't addressed in any. 
Activated charcoal and campfire charcoal are not the same. In a survival scenario, where does one obtain activated charcoal? Will campfire charcoal be an effective filter?
Water through activated charcoal equals cleaner water ( not purified, I know it still needs to be boiled ). Water through ash equals lye. In all the instructions I've seen, none mention the need to remove the ash from the charcoal before using it in the filter. In all the campfires I've ever had the charcoal has a layer of white ash on it. Is it necessary to remove the ash or not? Am I overthinking this?


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## cowboyhermit

Slow sand filtration has been proven for ages (albeit usually on a large scale), so has charcoal for removing impurities, both are completely sustainable and essentially free for people with access to the resources.

If a person thinks they might have to use a system like this to make unsafe water safe to drink then consider making one today and having the water tested (before and after) at intervals. Not very expensive if you do it yourself but in a lot of places there is a government office that will test if cost is a major issue.

I would hope that no one would HAVE to treat their water to make it safe on a regular basis (imo a well with no potential sources of contamination in the vicinity is preferable) of course that is not always possible. Personally when I was in a situation with questionable water I found boiling it on a woodstove to be the easiest solution. It really wasn't that onerous in the situation though it might be different if I lived further south:dunno:. Must have boiled several thousand gallons this way when I start adding it all up.

undumb, what you see in a campfire is not charcoal, to make charcoal you need to control the oxygen levels. Also charcoal that is made at home is not equivalent to Activated charcoal either. You are correct that the ash is not what you want to be using though, that would be bad.
http://www.preparedsociety.com/forum/f2/where-get-water-filter-charcoal-15688/


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## LincTex

undumb said:


> I've seen survival filter instructions online and in manuals that use three handkerchiefs with grass, sand and charcoal.


You are NOT over-thinking this! Those instructions aren't worth the paper they were printed on! (or worth the electrons to light the screen, LOL!)

I would not trust the water that comes out of the handkerchief filter you described.


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## cowboyhermit

Reading back in this thread reminded me about the biosand filters so I checked in with their current version and it appears that they have improved it again. While slow sand filtration is incredibly effective it can be difficult to scale down, the biosand filter achieves this with only a bit more maintenance and possibility for user error messing things up. There is no benefits over a slow sand filter (of which I have more experience), in terms of filtering but it is a much smaller undertaking to build one, and that may be important for many.

All the details on how to build one and the concepts involved are freely available http://www.cawst.org/en/resources/biosand-filter


















IF properly used and maintained these filters have no problem removing "all" bacteria and protozoa including tricky little buggers like Cryptosporidium. The only real area that it lags behind slow sand filtration is viruses but even that is not so clear apparently

http://en.wikipedia.org/wiki/BioSand_Filter 


> A recent study has suggested that virus removal increases significantly over time, reaching 99.99% after a period of approximately 150 days


Which is essentially as good as it gets with micro-organisms and a level that is difficult to achieve even with chlorine or other treatments. Contrary to what is often said, a few drops of bleach does NOT actually kill everything, far from it and in fact quite a few pathogens are resistant to chlorine, it is however effective enough in most situations.


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## LincTex

cowboyhermit said:


> Which is essentially as good as it gets with micro-organisms and a level that is difficult to achieve even with chlorine or other treatments. Contrary to what is often said, a few drops of bleach does NOT actually kill everything, far from it and in fact quite a few pathogens are resistant to chlorine, it is however effective enough in most situations.


Interesting.... most dental exam rooms and hospital offices are cleaned with nothing more then plain ol' bleach water.


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## cowboyhermit

LincTex said:


> Interesting.... most dental exam rooms and hospital offices are cleaned with nothing more then plain ol' bleach water.


And for 99.9% of bugs like you see on most labels that will do the trick, also cleaning solutions are a lot stronger than we can drink.

http://www.cdc.gov/parasites/crypto/resources/childcare_outbreak.pdf


> Cryptosporidium is resistant to chlorine disinfection so it is tougher to kill than most disease-causing
> germs. The usual disinfectants, including most commonly used bleach solutions, have little effect on
> the parasite. An application of hydrogen peroxide seems to work best.
> 
> Note: Cryptosporidium is not killed by alcohol gels and hand sanitizers so these materials are
> of little use in controlling an outbreak.
> 
> Note: The health department may instruct you to soak contaminated surfaces for 20 minutes
> with a 3% hydrogen peroxide (99% kill rate) and then rinse them thoroughly. No disinfectant is
> guaranteed to be completely effective against Cryptosporidium. However, hydrogen peroxide
> is more effective than standard bleach solutions.


http://www.cdc.gov/healthywater/swimming/pools/chlorine-disinfection-timetable.html


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## Hector827

So if I boiled water, and collected the condensation, will that work to get rid of anything that could be mixed in the water? Or is that just mainly for salt water? Like if I had a metal container that rusted up some in the inside and a little bit of rust was mixed in the water?


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## LincTex

Hector827 said:


> So if I boiled water, and collected the condensation, will that work to get rid of anything that could be mixed in the water? Or is that just mainly for salt water? Like if I had a metal container that rusted up some in the inside and a little bit of rust was mixed in the water?


Rust flakes, sand, etc. and other solids will stay behind. So will salt.

Distilling water will get rid of nearly anything harmful, except organic solvents that have a boiling point similar to water.


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## CaptNemo

landshark said:


> Good question, I don't know what sand would filter out, there has to be something that absorbs toxins that combined with purified sand and other things can do a semi-good job of it.
> 
> Anyone know if there is a way to filter out salt from salt water?


It's called nano-filtration... also known as reverse osmosis. There are hand held RO systems on the market with prices all over the chart. The Katadyne Survivor 06 Desal unit lists on their site for almost twelve hundred bucks. Amazon sells it for about 890. I'm sure this isn't the only one on the market. You just need to keep looking until you find something priced appropriately. Good luck


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