I’ve recently decided to take a more active role in my own emergency preparedness.

I’ve been looking at water filtration systems from the perspective of trying to figure out how good they are at removing contaminants. As no filter can kill viruses, naturally a secondary chemical disinfection would insure against the little nasties. My attempts to find information however on filter’s capabilities to deal with chemicals has left me unsatisfied. The descriptors used with active carbon seem to always be removal of taste and smell. Other methods also clearly seem to indicate stuff still gets through.

So if you had to assume the water was contaminated by more then just microscopic lifeforms, just how well do these things perform? If we assume the absolute worst case scenario and the water was laced with CBR contaminants would your normally available man portable filtration systems and chemical disinfection serve you against more then just the B component?

There is one system I know of that pass the gold standard test (US EPA) for virus removal - the General Ecology First Need filter http://www.generalecology.com/portablesystem.htm

We probably get at least a significant reduction in viruses from the other decent filters due to clumping and adhesion, but none are certified and I would guess do not do a good enough reduction in the tests to meet "purifier" standards.

Filters will do fine with fallout but there's not much they can do with soluable isotopes. Long discussion and I'm not an expert...

Chemicals... the ones with activated carbon filters will at least reduce the presence of chemicals, but I have not seen any data on how much and for how many liters of water.

Storing water for shelter-in-place is a sure thing. A filter backup and chemical backup to that don't cost much. There are plenty of expedient means of accomplishing most of what you are interested in, but none are what I would call portable.

HTH,

Tom

Charcoal filters will remove more than taste and oders. The manufactures will not say so from a liability stand point. So they deal with many of the chemicals you are concerned about. But will have a greatly reduced life span.

But say we are dealing with a witches brew like the contaminated waters around New Orleans after Katrena.

First I would rather go elsewhere for a better starting soure. But saying there is no other choice I would not bet my life on a single method. Rather I would use a multi tier approch.

First would be a gravity sand filter. I'm speaking of tricking water through a foot or better yet several feet of sand. This would be in layers of several grades or grain size of sand from couarse to fine. This would not really decontaminate really bad water but would remove many of the larger contaminant particals.

I would then use a distilation process. This could either be a heat source [Such as fire] driven still. Or it could be a solar powered method. With this the first and last portions would need to be discarded. Because of volitile liquid contamination. Those with a lower boiling point like petrolium products or those with a higher boiling point would be the first or last products cooked off. with the water in the middle portion. This is called fractional distilation. Usually spoken of when dealing with petrolium production. But the one thing that distilization will remove for sure are disolved solids and suppended solids such as the nasty parisites we are normally concerned about.

I would still not compleatly trust the result from a multiple contaminated water source. So I would then run it through a charcoal filter. Then to be sure I would run it through a reverse osmosis filter.

True all this isn't really man portable but more of a fixed site solution. But if you are dealing with chemical contamination it can be very complicated depending on what chemicals may be involved. But in a portable method charcoal filters would be the most likely to be portable and effective. Reverse osmosis gilters are on a par with charcoal but are less portable, less available and more expensive.

Intermediatly effective is distilation. The most portable would be a solar still such as shown in many survival books. A sheet of plastic, a hole and a catch container. But more perminant set ups can be nade of glass or ridged plastiic panes and metal back plate. But you need to monitor the different fractions.

The first need fitlers seems to be the best portable pump filter for removing chemicals. The filter itself is a big block of black carbon matrix. Which is also it's disadvantage, you can't clean it, just backwash it.

Other filters have smaller carbon ellements. If you have many filter already, you could try to use food dye and seem how much color your filter absorbs. The first need absorbs all color dye.