Water filtering

[Chance]

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]

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."
uppy_dog

 

[crazydave]

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]

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]

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]

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

 

[leon-1]

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.

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?

 

[Tadpole]

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)

 

[leon-1]

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.

 

[andy_e]

...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]

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]

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]

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

 

[stijnb]

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]

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]

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

 

[leon-1]

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]

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]

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]

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.