View Full Version : Water filtering
Been searching the internet, Lofty's Survival book, the T J Elpel book and nothing.Done a search here too but couldn't find any either.
I have a MSR filter but am looking for a three tier layered filter with natural materials. Think is was three pieces of cloth, above eachother. In the first one rough gravel, second finer gravel and the lower one fine white sand. Water poured on top and filtered its way down.
Does anyone have proper information?
Not sure if it helps but I have a homemade water filter. I made an open based cone out of an old canoeing cag (it's waterproof) and in the bottom (the point)have a simple bung made from half a dozen layers of cloth (the bung is tight so the cloth type is pretty irrelevant).
It's slow but I have used it with success over the last year or so. When I tested it, I took a handful of peat and mixed it with a litre of water. It took over an hour to filter but the water was crystal clear after filtering.
Obviously the filter can be cleaned quite easily.
Oh, and I still boil the water :)
Been searching the internet, Lofty's Survival book, the T J Elpel book and nothing.Done a search here too but couldn't find any either.
I have a MSR filter but am looking for a three tier layered filter with natural materials. Think is was three pieces of cloth, above eachother. In the first one rough gravel, second finer gravel and the lower one fine white sand. Water poured on top and filtered its way down.
Does anyone have proper information?
Christy I'll check through some of the stuf that I have here, from what I can recall you pretty much have it, but the final tier (lowest) was a layer of charcoal bottomed out by something like cotton wool before the lowest layer of cloth.
somebody made one of those filters during a dutch meet-up. The guy works for a tap-water company and was able to let the water be tested in a lab. Water from the 3 layer filter they build contained more bacteria than non-filtered water, when tested in the lab.
here is a atricle about a variation of the 3 layer filter. http://www.therangerdigest.com/Tips___Tricks/Filter_and_Purifying_Water/body_filter_and_purifying_wate r.htm
i use a milbank bag then puritabs, never had any probs only trouble is the water can have a slight taste/ smell from the tabs, but nothing major,
somebody made one of those filters during a dutch meet-up. The guy works for a tap-water company and was able to let the water be tested in a lab. Water from the 3 layer filter they build contained more bacteria than non-filtered water, when tested in the lab.
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That's rather worrying! I was thinking to filter this way to get most of the lumps and chunks out, then boil it anyway. But this doesn't sound too great.
Will check out the link.
The puritabs area last resort option to me. The MSR is ok in filtering and the tabs give me unpleasant side-effects. Have drunk water in the bush heavily loaded with chlorine, there was no choice. It cleared all the good bacteria too and that was not nice.
Some people can't stand the after-taste from chemical purifying but hey, lace it with lemon powder or somesuch (not so good with coffee, mind). Personally I boil it but that's really down to taste :)
Millbank bags are great (it's what I was making as described earlier in the thread) - pretty much bombproof. I could have bought one but since I had the materials......
The problem with natural (in-situ) filters, is that the water will always be contaminated by the last filtration stage (whatever it might be). So you really need to be able to clean each filtration layer properly before use (which can be difficult with natural materials).
Consequently, it doesn't surprise me that a natural filter can increase the bacteria content of the filtered water. However, remember that it is extremely difficult to filter out bacteria (and almost impossible to filter viruses). That's why water treatment should always be a two stage affair - filtration followed by purification (either chemical or through boiling). Don't mix the stages up and if boiling, allow the water to boil hard for a couple of minutes.
Here endeth the lesson :)
mantic, try my good friends at jay jays surplus in sheffield, they sell unissued milbank bags for £2.99 not as cheap as making your own, but they are the real deal, the one i was looking at was dated 1978, still in its original packaging, lol
Cheers Hilltop - the cheapest I had found was 20 quid, which (though it sounds really miserly of me) is too much for what amounts to a cloth bag. I'll seek one out from your mate (good to have a spare). :notworthy
That's rather worrying! I was thinking to filter this way to get most of the lumps and chunks out, then boil it anyway. But this doesn't sound too great.
Will check out the link.
The puritabs area last resort option to me. The MSR is ok in filtering and the tabs give me unpleasant side-effects. Have drunk water in the bush heavily loaded with chlorine, there was no choice. It cleared all the good bacteria too and that was not nice.
Christy the clue is in the name, it is a filter not a purifier, the whole point of it is to remove particles or matter from water. Bacteria and the like can then either be treated by using chemical (iodine, chlorine or silver based) products or by boiling. Leave the water boiling for a while (a rolling boil) to allow time to kill off any biological nasties.
The area where I'm looking to do most of my activities (southern Poland) is in general pretty nice but there are problems with heavy metal in the water. Having been informed by a medical doctor friend that the main problem with these is accumulation not short term it's not a great survival issue. However I'd still like to know how to get rid of the nasty stuff and know if there are any chemical purifiers not to use because of reactivity issues.
Domestically the tap water is just as bad - i used a Britta type filter for a while but mostly bottled water.
Thanks for the help and don't be afraid of giving me the technical explanation!
Removing heavy metals from water is notoriously difficult - I'd invest in a ceramic filter or minimise how much water you drink from suspect sources (whether filtering or not).
Sam, I am no expert, so I have just been doing some research.
The university of Oxford have been looking into removing heavy metals from drinking water. They have come up with a form of activated carbon, by the sound of it, that is effective in removing Cadmium, Lead, Arsenic and Zinc from water.
MSR filters have a carbon section in them (they say that it reduces the taste of chlorine) and First Need filters (which state they are capable of removing some chemicals) are non chemical and ecologically sound may be filters for you to look into.
I haven't yet seen a pocket filter that advertises that it will remove heavy metals from drinking water, but I am only one person.
I wish you luck in finding a filter that will work.
unissued milbank bags for £2.99
Ok I give in. What's a Milbank bag? Searched and Googled but nothing. Sorry, English is not my mothertongue :o
wingstoo
28-05-2006, 18:14
Ok I give in. What's a Milbank bag? Searched and Googled but nothing. Sorry, English is not my mothertongue :o
Hi Christy,
Will bring mine along to the meet in July so you can have a look at one...Thanks to British Red for the gift...http://img140.imageshack.us/img140/7227/nomadcompletesystem8nt.th.jpg (http://img140.imageshack.us/my.php?image=nomadcompletesyst em8nt.jpg)
Will also hopefully have a go at making some water filters from sand, charcoal and a 2ltr pop (soda) bottle...
LS
I have not tried it, but I read that you can remove the iodine taste with a vitiman C tablet or powder, 1000 mg for a liter
Has anyone tried this?
crazydave
11-06-2008, 02:17
yep it does but not sure how. I've got an ex issued camelbak and I cant get the iodine taste out of it. either that or its repurifying everything thats put in it :)
yep it does but not sure how. I've got an ex issued camelbak and I cant get the iodine taste out of it. either that or its repurifying everything thats put in it :)
Try lime juice in their Dave.
I use a Milbank bag regularly to filter the main muck out.
http://www.ravenlore.co.uk/assets/images/millbank.jpg
And then just boil the water to kill any nasties.
Works for me, but then again I still glow in the dark from being out on the hills for the fortnight Chernobyl went up. I didn't know anything about it till I got back home.
maggieforrest
11-06-2008, 12:36
Hi Christy,
Will bring mine along to the meet in July so you can have a look at one...Thanks to British Red for the gift...http://img140.imageshack.us/img140/7227/nomadcompletesystem8nt.th.jpg (http://img140.imageshack.us/my.php?image=nomadcompletesyst em8nt.jpg)
Will also hopefully have a go at making some water filters from sand, charcoal and a 2ltr pop (soda) bottle...
LS
I have already tried the 3 pop bottles each has a layer of moss at the bottom to stop my filter media disappearing.
This was to prove filtering can be done with things you find in a survival situation. As is was for a survival challenge scout badge award. Obviously boiled afterwards also.
Bottom Bottle has sand - should be silca sand (but I used builders sand - very well washed) - with a layer of moss at the bottom.
Middle Bottle has barbeque briquette or lump wood or chard wood from your fire - with a layer of moss at the bottom.
Top Bottle had just moss - completely filled.
Each bottle was taped together with gaffer tape.
This was tested using really dirty river water.
The water started cloudy and grey, what came out was clear but green from the moss.
I then boiled the water for roughly 3 - 5 minutes on a rolling boil.
And drank some of it - it tasted a little peaty, but apart from that it was OK and no I didn't get stomach ache or the runs, etc.
I have been doing this method with the scouts for a few years now as this is the similar technique as used to filter water at water treatment centres, they also add further chemicals and the filter media is slightly different, but you get the idea.
The scouts have to use this technique with a sock believe it or not. Some of the time, if the sock is lined with leaves it works if you use moss at the bottom, then ash, then chard wood, then moss.
Margaret
Removing heavy metals from water is notoriously difficult - I'd invest in a ceramic filter or minimise how much water you drink from suspect sources (whether filtering or not).
Unless it's particulate, I'm not sure that a ceramic filter by itself will remove heavy metal contamination: I certainly wouldn't want to use mine near Dounreay.
A couple of keystrokes came up with this, though: http://www.pureeasy.com/products/pro_sportEN.htm
Grooveski
11-06-2008, 13:25
Works for me, but then again I still glow in the dark from being out on the hills for the fortnight Chernobyl went up. I didn't know anything about it till I got back home.
I was out hiking in that rain as well. First I heard was when they slaughtered all the lambs on the island.
"Erm, why are you killing the lambs?"
"Och, they all got caught out in yon radioactive cloud a couple of weeks ago."
:puppy_dog
crazydave
11-06-2008, 14:37
Try lime juice in their Dave.
is that real lime juice or will roses lime cordial do? I was thinking of doing something like that anyway to try and improve the taste a little. I wonder if the vitamin C in it does anything.
hey maggie I take it the tribe got home okay then once dan had put his boots back on :)
British Red
11-06-2008, 14:41
Please bear in mind that adding either ascorbic acid (Vit C) or citric acid (lime juice) will deactivate iodine - a waiting time is vital. In addition if residual acid is left in your water bottle (quite likely with tablet form Vit C) it can deactivate iodine the next time you use it and let bacteria and organisms survive. If you must do this its sensible to decontaminate in one bottle and use the acid base in a different one that you fill from the sterilised bottle after a 10 minute wait
Red
crazydave
11-06-2008, 14:44
as for filtering muck out a spare pair of trousers with one leg inside the other then tied in a knot is very good at sieving out crunchy bits and can do a lot more than a millbank bag. made and used pop bottles but never trusted the sock as I dont like cheesy tasting water :)
I've got a load of bottles which have filters in them so you drink direct from the bottle. they suggest iodine or chlorine if you really arent sure but not to worry as the charcoal in the filter should take the taste out.
the instructions on the kits generally say leave for 5-10 mins before adding vit c my travel cup reckons most water can be drunk straight after passing through an iodine resin filter but if in doubt leave for three mins to kill residual bugs that may have come through.
British Red
11-06-2008, 14:48
Same principle there - if you run the water through the charcoal before the chemical has worked, the water is not safe. Very few toruser materials will filter as finely as the swollen fibres of a millbank bank. Larger particulates crossing the coarse filtration barrier will raise the chance of organisms being insulated from the actions of heat or chemicals. Its an acceptable emergency strategy but no substitute for a proper filter
Red
the instructions on the kits generally say leave for 5-10 mins before adding vit c my travel cup reckons most water can be drunk straight after passing through an iodine resin filter but if in doubt leave for three mins to kill residual bugs that may have come through.
Dave most of these things are pretty good nowadays, but 5-10 mins is not enough, weather conditions (heat and cold) along with altitude can have quite a varied effect on how long a lot of the sterilising agents take to do their job, 20 mins in one study at least at sea level (can't remember the temp for that one).
Roses has sugar in it mate, the inside of the bag will end up festering unless cleaned thouroughly, better bet is real lime juice after at least 20 mins.
I use a Milbank bag regularly to filter the main muck out.
http://www.ravenlore.co.uk/assets/images/millbank.jpg
And then just boil the water to kill any nasties.
Works for me, but then again I still glow in the dark from being out on the hills for the fortnight Chernobyl went up. I didn't know anything about it till I got back home.
Wayland is that a ten liter millbank bag that you have there?
I think many people are put off from using a Milbank bag because they don’t know how to use it. I hear you asking how hard it is, pour water in one end (the one with the hole) and let it flow in to the tin mug.
A Milbank bag only really works when thoroughly wet, by that I mean the canvas from which it is made has had long enough in contact to water to swell, when this happens the bag becomes as effective as it is going to get at filtering out the organic bits, the mud, the grit, and the ‘floating bits’.
Problem is that swelling slows down the rate at which the water flows, convincing the users that their bag is blocked. When it is not blocked or clogged, it was working properly.
I did a course year before last and the instructor told us all that the first billys worth of water through the bag had to be but back in the Milbank as it was not fully filtered, it was not working properly until the bag was wet.
My question is, would not pouring dirty/contaminated water directly into the cup you are going to use for your clean water, make the cup dirty/contaminated, no matter how many times you clean the water it’s pretty pointless if the cup is full of contamination.
(I know you should boil all your water anyway)
I think many people are put off from using a Milbank bag because they don’t know how to use it. I hear you asking how hard it is, pour water in one end (the one with the hole) and let it flow in to the tin mug.
A Milbank bag only really works when thoroughly wet, by that I mean the canvas from which it is made has had long enough in contact to water to swell, when this happens the bag becomes as effective as it is going to get at filtering out the organic bits, the mud, the grit, and the ‘floating bits’.
Problem is that swelling slows down the rate at which the water flows, convincing the users that their bag is blocked. When it is not blocked or clogged, it was working properly.
I did a course year before last and the instructor told us all that the first billys worth of water through the bag had to be but back in the Milbank as it was not fully filtered, it was not working properly until the bag was wet.
My question is, would not pouring dirty/contaminated water directly into the cup you are going to use for your clean water, make the cup dirty/contaminated, no matter how many times you clean the water it’s pretty pointless if the cup is full of contamination.
(I know you should boil all your water anyway)
Tadpole your instructor should have mentioned that before filling with water the millbank bag should be soaked thoroughly, screwed up and even mashed into river silt. The millbank is then filled directly from the river and hung until it reaches the black line (this allows all particulate matter to flow off the outside of the bag), by the time it has reached the black line it will be a very effective filter then start filling the water bottle billy or mug.
On the group filters there is no line, the reason being that by the time you hang it up it will have washed any particulate matter from the outside of the bag anyway.
Your instructor was badly mistaken in the information he passed onto you and yes if he had been correct it would have passed on any particulate contamination with it, but be aware that all water that comes through a millbank is considered contaminated as it has not been sterilised by either boiling or chemical means, it has only been filtered and not sterilised.
Once water has been sterilised and allowed a soak period you are supposed to flush the threads on your water bottle so you can drink directly from the bottle without catching nasties.
...My question is, would not pouring dirty/contaminated water directly into the cup you are going to use for your clean water, make the cup dirty/contaminated, no matter how many times you clean the water it’s pretty pointless if the cup is full of contamination.
(I know you should boil all your water anyway)
The Millbank is only used to visibly clean the water, AFAIK even boiling or chemical treatment may not always kill off all bacteria that are lurking inside dirt particles in your water.
maggieforrest
11-06-2008, 17:16
hey maggie I take it the tribe got home okay then once dan had put his boots back on :)
Thanks for the message, the tribe got home very tired after a stay at Cranham. Dans clothes under his waterproofs were not only dry, but also clean. Only his boots and socks were dirty and smelly.
Nomad course was fantastic and he has made 5 metres of nettle string so far.
British Red
11-06-2008, 17:18
My question is, would not pouring dirty/contaminated water directly into the cup you are going to use for your clean water, make the cup dirty/contaminated, no matter how many times you clean the water it’s pretty pointless if the cup is full of contamination.
(I know you should boil all your water anyway)
Yup.
A Coarse Filter will not remove even the large micro organisms (Protozoa for example). So why do it? Because if there are lumps in your water (particulates), the lumps act as an insulator preventing sufficient heat getting to the organism to kill it. When ingested, the particle breaks down in the gut, the organism is released and you get ill.
So, if you do get particulates running through, clean the mug in fast flowing water or in some other way (bandana) wipe out all particles prior to re-filling
Red
Humpback
11-06-2008, 17:26
SNIP...
My question is, would not pouring dirty/contaminated water directly into the cup you are going to use for your clean water, make the cup dirty/contaminated, no matter how many times you clean the water it’s pretty pointless if the cup is full of contamination.
(I know you should boil all your water anyway)
You've answered the question.The bag removes big stuff and does not in any way deal with contamination - boil or treat filtered water.
The key point is, as with your question, to use a utensil that will be sterilised by boiling the filtered water such as a billy. I would not filter into a drinking cup direct to avoid the cross contamination you allude to. In fact I have a folding bowl to collect into which is then emptied into the billy/kettle and is kept for 'grey' water.
Hope that helps
if you ad soda CaCO3 to the whater, the lead will react with the CO3 and become solid PbCO3 wich can be filtered out very easy.
Don't know about other heavy metals though.....
has anyone tried to make a carbon filter yet? could be pretty easy with just some sort of funnel, a tampon and a bit of norit......
crazydave
11-06-2008, 18:55
I have a bag of charcoal pellets from spare cooker hood filters and coffee filters for the travel cup just to help strain out as much as I can. I seem to remember that millbanks can filter cysts out but may be wrong. mainly the ones we had were for pulling manky bits out of soupy water. if forgotten and left though they can get rather funky with mildew. the only time they seemed to get issued though was on jungle trips.
the old screw on PWP's when we got them were much better as they were designed to remove chemical contaminants as well post battlefield - I liked them but havent seen them for a while since the smaller pump type ceramic units have taken off. the closest thing I've found are the charcoal/iodine resin tops you can get for sports type bottles or the military style ones I have which is good for 500 litres or so. I have a pump somewhere but it disappeared in the move. a lot of work for water though :)
Ogri the trog
11-06-2008, 19:40
Having just read the thread from the beginning, I feel a little late to join in.
I'm quite happy with teh methods I employ to filter & purify my water (milbank/boil with iodine/chlorine as chemical back up).
My query concerns the first post of the thread, and the idea of filling three seperate filter layers with gravel/sand etc. My first thoughts were that this action is merely pre-contaminating your fresh filter media (even if it is only Tee shirt material), and secondly, the microscopic pores in the gravel would harbour the nasties that could be washed into your (roughly) filtered water.
Can I call upon the collective wisedom of the forum to confirm or refute my suspicions without diverting attention from the importance of the core topic?
TIA
Ogri the trog
Having just read the thread from the beginning, I feel a little late to join in.
I'm quite happy with teh methods I employ to filter & purify my water (milbank/boil with iodine/chlorine as chemical back up).
My query concerns the first post of the thread, and the idea of filling three seperate filter layers with gravel/sand etc. My first thoughts were that this action is merely pre-contaminating your fresh filter media (even if it is only Tee shirt material), and secondly, the microscopic pores in the gravel would harbour the nasties that could be washed into your (roughly) filtered water.
Can I call upon the collective wisedom of the forum to confirm or refute my suspicions without diverting attention from the importance of the core topic?
TIA
Ogri the trog
It's a fair question, the main reason for this specific type of filter is removal of particulate matter. The three stage filters are effective when used in the correct combinations and they can be more than three stage.
Top layer being moss, second layer being cloth, third layer being sand or silt, fourth layer cloth, fifth layer carbon (normally taken from the fire), sixth layer cloth, then a layer made from a field dressing.
This will filter out most particulates, but will not remove cysts, crypto or any of the other nasties.
Boiling or chemicals are the beastie for this specific job.
British Red
11-06-2008, 21:17
Ogri,
Multi stage filters are, or can be, hugely efficient - especially a properly constructed bio sand filter - they can filter as well, if not better than a carbon cermic filter. The key point though is the term "properly constructed". We are talking something several feet deep here. Over a week to three weeks a layer of organic matter (schmutzdecke) forms which acts to render safe micro organisms - all the larger material is filtered out by sand. They are cheap, have a near infinite lifespan, can be made from the simplest of materials and by unskilled peopel. BUT they are not something portable - they are huge and weigh tonnes (literally) - but for a tiny amount of money you can build a filter that will produce clean safe water for a whole community
http://www.cawst.org/index.php?id=128
Red
crazydave
11-06-2008, 21:45
must be 25 years ago we did a school trip to a water treatment works. they bubbled water into the filter tanks from below through graded gravel and finaly sharp sand. that was then decanted off and chemically treated before being shoved down the pipes. the filter was about a meter thick the size of a swimming pool and took a jcb to empty and refill. they had three of them with one being renewed at any time.
fascinating :)
who did the thing on home made carbon ceramic filters made by baking used coffee grounds in clay was it here or another forum I read? the intention was for africa to be able to make clean water from available aboriginal technology
crazydave
11-06-2008, 22:21
I like using these as they just replace the US bottles I use which dont taint the water as much as the UK ones they are a squishy bottle and I use one to top up all the other bottles. I've sent a few out to afghanistan as well.
http://web-tex.co.uk/surviva-pure-due-june-2008/canteen-water-bottle/prod_1447.html
I cant believe the price though as I got 3 from the states for that price. the inline filter for camelbaks is meant to be very good. :)
Wayland is that a ten liter millbank bag that you have there?
Nah.. Just the standard one.
Outputs about a pint per hour.
I hang it when I set camp. Boil up before turning in and put it in the bottle it when it's cooled in the morning.
(unless it's really cold in which case I bottle it hot, wrap it in a shemagh and use it as a hot water bottle.)
Takes less than a couple of minutes effort to sort over two litres of usable water by my reckoning (http://www.ravenlore.co.uk/html/water.html).
Though it is a bit heavy compared to other filter systems, I find the First Need System to be my favorite water filter. I think it does a better job of all-around filtration. Cysts, chemicals, bacteria, and I think some viruses (not sure on that one), I have used them in the swamps of North Carolina, the bogs of Minnesota, drip tanks in the North Dakota Badlands, along with water from Lake Superior on scuba trips. Beats the heck out of iodine, halzone, and chlorine. I will carry tablets as a back-up system, or if I have to go ultra-light, but I prefer something that reduces pesticides and herbicides in my drinking water. Years ago I and about eighty other Marines were treated for a bad case of dysentary, so I take clean water to be a major concern!
Thinking about it, I do also carry Aqua Mira in my kit in case it's impractical to boil the water, but I've never used it yet and I think it's about to go out of date..:dunno:
Podcast Bob
13-06-2008, 08:37
No one here seems to be mentioning the Aquagear Survivor Bottle which is currently taking the market by storm, as the best value for money filter AND purifier, removing all the nasties, heavy metals, chlorine and iodine, taste and taint, and is completely tested and approved by the MOD up to 400 gallons (they gave up after that!).
I did a podcast with the importer which may be of interest to readers of this thread, if you haven't heard it.
Either over on The Outdoors Station, or direct link here;
http://www.hipcast.com/export/P793d09abbffb64d5966f2576dc367 6baYlp9SlREY2d2.mp3
crazydave
13-06-2008, 21:49
same principle as the seychelles pres 2 pure ones I use, what I dont like is the filters swell up and soften so you need to be carefull with them. this upside down system works well or so I've heard
has anyone tried to make a carbon filter yet? could be pretty easy with just some sort of funnel, a tampon and a bit of norit......
Next weekend's your chance than mate. :D
robtheblacksmith
29-06-2008, 13:02
I havent been here in a while and I do not claim to be the smartest guy, but I thought I might add to this:
Some years ago my ex's parents lived in the mountains of North Carolina and there was a neighbor who had a 4 meter x 1 meter concrete pipe buried right next to a stream rolling off the mountain with about half a meter sricking out. They filled it with about 2 meters of sand leaving room at the top for clear water.
The idea was to let the water seep up from the bottom and filter as it rose since water seeks its own level.
Based on this, I was fooling around with a rather large peice of bamboo ( because there is an abunbance where I currently live) about 2 meters long and 4cm wide, hollowed out of course. I put a chunk of denim in the bottom and alternate layers of natural charcoal and sand for the first half a meter or so, then just sand.
To be honest, I used some water I mixed with some dirt from the back yard and when fltered, it worked better then I thought it would as it was quite clear.
However, based on an event that I witnessed when I was in Scouts, you will never catch me using water that has been abo filtered and NOT boiled. It wasnt pretty and the memory has stuck with me.
Again, this was just something I fooled with and I never put it to the trail test or actually applied it, but the theory seems sound and the results werent that bad.
Rob