I am trying to rid myself of the water filter weight.

What about using a coffee filter and small plastic funnel or conical paper cup w/ bottom cut off?

Chicks on the AT turned me on to using pieces of panty hose for filtering large floaties. Just poke a swatch into the bottle neck and pour the water in. When done, pull the swatch out, shake the floaties off and pin the swatch to the outside of your pack.

In the course of reworking my water treatment system, I did some investigation of the pore size of standard paper coffee filters, and came across this interesting web page:

http://www.princeton.edu/~pccm/outreach/scsp/mixturesandsolutions/diatoms/coffee_filter.html

So it appears paper coffee filters have a pore size of somewhere in the range of 15 microns or less. Of course, each brand of paper coffee filter is no doubt made to different specifications, and given the cheapness of these paper filters and the fact that the application is not critical, don’t be suprised to find a 100 micron hole in a filter now and then. If you want guaranteed pore sizes for a paper filter, then you’ll need to use laboratory filter paper, such as that sold by Whatman Corporation.

Anyway, the technique I’m experimenting with is to screw a standard paper coffee filter (or maybe two filters in succession, in case one is defective) under the large cap of my dromlite bladder, then attach a Seychelle filter to the bladder and then drink from the outlet port. The tubing between filter and bladder is just 1″. Because the coffee filter blocks the water flow to some extent, I find it necessary to squeeze the bladder to make water come out. Otherwise, everything seems to work pretty well. The wet filter plus tubing and connector for the bladder weighs about 125 grams (4.4 oz). (The dry filter weighs less, obviously.) Add another 20 grams for the backflush bulb, which I plan to carry, but which I will only use in campgrounds and hotels.

These coffee filters are suprisingly durable (I’m using the 50 for $0.59 version from Walgreens), as well as very lightweight (about 10 grams for 30, once trimmed to a diameter of 4″). The purpose of the paper coffee filter, of course, is avoid mucking up the Seychelle filter too fast.

This system should have no trouble screeing the helminthic parasites and their eggs (supposedly the eggs are 25 microns), which is my real concern outdoors, since I know sheeps and dogs carry some of these things. The Seychelle filter should also screen fairly well for Giardia and Crypto, though I’m not too worried about those.

This system won’t screen all bacteria or viruses, however I’m not too worried about these either, at least in North America or Europe. The Third World is another story, of course. Definitely don’t want a repeat of that week of hell down in Guatemala, spewing blood, liquid shit and mucus out my ass every time I sat down on the toilet, which was like twenty times a day…

Frank, My web searching research some months ago revealed a nominal 5-15 micron pore size for paper coffee filters. However, just like you said pore size is not controlled, so an absolute largest pore size number is NOT even given.

My purposes were somewhat similar to yours. How to eliminate Hydatid tapes (canine fecal origin) so chems or UV-C would work to eliminate the remaining bugs. However, I would use the coffee filter as a pre-filter, and then employ AqM or UV-C.

Do you feel confident that the paper filters are robust enough? As a pre-filter used in filling a bladder/bottle, the paper filters are easily inspected. As an in-line pre-filter, they are not easily inspected for perforation. I guess I’d do some testing at home with slightly turbid water – attempting to replicate clogging conditions since more squeezing/pressure will be needed to produce water flow. How many times can you fill and squeeze empty the bladder before the paper filter perforates or deteriorates? This would be the goal of my testing of multiple specimens from the same manufacturer.

Main drawback to the coffee paper pre-filter in my case is it’s slow. Not as much of an issue with the in-line pre-filter approach that you’re using.

As far as NA flukes are concerned, you mentioned sheep. What you’re thinking of is Fasciola hepatica. Primarily (I hesistate to use a superlative like always, etc. in this case), infection is caused by eating vegetation (F. hepatica). Once the cercariae are released from snails (aka the intermediate host), they swim to nearby vegetation and encyst on the vegetation (now often called metacercariae after encysting, IIRC). Sheep or humans (aka the definitive host) must eat that vegetation (humans? well, maybe something like water cress??? definitely water chestnuts in geographical areas where they grow) in order to become infected. I said “primarily” because since the cercariae are briefly free swimming, why couldn’t one or more be picked up when filling a water bottle? Logically, I don’t think we can say with 100% certainty that it can’t happen.

So, step one is, if you can avoid taking water from a source with obvious snails present, don’t take that water.

Any other thoughts?

Yes, Paul, I don’t trust these paper coffee filters myself anymore after doing much experimenting this evening. I’m going to chuck them in favor of a piece of supplex nylon as a first prefilter (screwed under the cap of my dromlite), then a siltstopper as a secondary prefilter, and finally the Seychelle filter. I will be bringing MSR sweetwater chlorine (same as bleach) but don’t expect to use it for treating water. My opinion is that it’s a lot simpler just to get sick and then let the body build up an immunity to the sorts of bacteria and viruses found in North America and Europe.

The siltstopper is overkill, but I need some sort of backup in case the Seychelle clogs up, since I need something that will last several months. The siltstopper is supposedly 5 microns and that will stop the worm eggs even without the Seychelle filter.

The helminthes I’m worried about are Echinococcosis Hydatid. According to this article, these worms exist in sheep, goats and dogs, and apparently the rate of infection is fairly high in Greece, where I will be hiking. Given that most greeks live in the cities, I imagine the rate among the shepherds in the mountains is much higher than the rate for the population as a whole. Whether these shepherds are getting the worms from touching the sheep and dogs and then not washing their hands before eating, or whether it is from drinking the water, I don’t know. But the complications associated with these worms sound very serious.

I have been searching for information about what it takes to kill helminthes and their eggs, but haven’t found anything authoritative yet. I assume it is easy to kill the adult form with any of chlorine, iodine or chlorine dioxide. But what about the eggs? Are they perhaps as resistant to these chemicals as giardia and cryptosporidium cysts? No one seems to know, or even to care. Meanwhile there is all this hysteria about Norwalk virus and other trivial stuff which does nothing but cause a little diarrhea.

The other thing I’d like to know is what is the pore size on supplex nylon. It certain seems finer than the 80 microns quoted for the metal pre-filter of the MSR Sweetwater guardian, but I can’t tell if the nylon is as fine as the coffee filters. It would be really nice if I could find some fabric that was fine enough by itself to stop the worm eggs, which are supposedly 25 microns. Because like I said, helminthes are really the ONLY thing I’m truly worried about (at least in North America and Europe).

Frank,

Generally speaking from the human standpoint as the definitive host, the infective stage, in this case an egg (different infective stage compared to flukes) of the Hydatid tapeworm (Echinococcus granulosis and 3 other species) and all tapeworms eggs which humans shed in their stools, for that matter, are very highly resistant to dessication, chemical disinfection, and UV-C sterilization. IIRC, heat/boiling will do them in though. Basically, nothing the hiker will carry will kill the infective stage. It must be prevented from entering the water that will be drunk by means of filtration. You’ve got the size right, IIRC. I’d go a little smaller, like 20 microns for safety purposes, but perhaps I’m just being overly cautious.

As far as how a human generally gets infected with Hydatid tapes, here is how it occurs to the best of my recollection (its been over 30yrs since i studied parasitology, so you may want to verify this info):

0) wild canines or feral dogs get infected from eating infected animals like sheep, goats, cows, and also, wild herbivores like deer, moose, roos, etc.

1) infected canine defecates in water or run-off carries fecal matter and Hydatid eggs into a water source.

2a) a hiker drinks the unfiltered water from that contaminated source and ingests some eggs.
2b) the shepherd transfers eggs from their sheep/shepherd dog feces/fur/anal region to their lips/mouth via their fingers or an inanimate object. Possibly also, allowing an infected dog to lick your hands (and forgetting to scrub them good), or your lips (remember dogs have a penchant for licking their hintermost parts). I never let any dog lick my face and always wash my hands after they lick my hands or I pet them.

Flatworms have a complex life cycle with different stages. NOT ALL stages are capable of infecting the same species. “Different strokes for different folks”, so to speak.

Ok, now here’s the point you may want to verify. I’m not sure that eating infested, undercooked animal flesh will give us the infection. It’s the wrong life cycle stage, IIRC – but, please verify this, but I don’t recall that humans can be infected this way – IN THE CASE OF HYDATID TAPES – other parasites yes, e.g. Trichina spiralis, Taenia solium, etc. Definitely, contaminated water can lead to infection. Symptoms of the infection may not show up for up to 20yrs. As you are already aware, these little guys are different from the more common beef, pork, and fish tapeworms. They’re very small and they leave the intestines and infect the liver, lungs, and brain, and possibly other organs (I’m forgetting now).

You’re right. Don’t mess with these little buggers. 12-18mos ago G.R., on these Forums alerted me to their presence at Isle Royale – didn’t know, at the time, that Hyadatid tapes were also indigenous to that Park.

Enjoy Greece. We’ll be here when you get back. Hope you don’t mind sharing your adventures with us.

Frank, a thought just occurred to me, water about using the Siltstopper filter sold on this website in your inline filter system. It’s a pre-filter with a 5micron pore size. That will easily eliminate your Hydatid tape eggs and some protozoans too. Just a thought.

I am using the supplex nylon screwed under the lid of the dromlite as my initial filter, followed by a siltstopper, followed by the Seychelle filter. This is overkill for helminthes, but there’s no reason to get myself reinfected with Giardia if not necessary, which is why I’m including the Seychelle filter. (I’m sure I’ve had Giardia in the past, since I didn’t bother treating water until this past season.) Also, both the Siltstopper and Seychelle filters are new for me, and I don’t know how they will work in the field, which is why I am bringing both, plus 3 spare Siltsopper filter cartidges (these only weigh about 2 grams each!), plus the Seychelle backflush bulb, plus some Micropur tablets to disinfect my water bladder now and then. If either the Siltstopper or Seychelle filter causes me problems, I’ll discard the troublemaker and rely solely on the other one.

Frank, clearly, you’re quite prepared. Based upon my reading of all of your posts, this should come as no surprise, and it doesn’t. Sounds like you probably don’t need another pre-filter with a 20micron pore size unless the water is very turbid. I understand that you don’t want to have the SiltStopper clog. Enjoy Greece.

here’s my home-made solution to stop small debris getting in my platy when filling:

http://www.brettonstuff.com/index.php/backpacking/ultralight-water-filter-cap/

it’s working well so far…

Platypus bottle cap filter – click here, then scroll down the thread for pics.