Homemade 1 micron filter?

[Stephen Barber]

Is anyone using something like this gent demos?

http://www.youtube.com/watch?v=is7X6JS9vUo

Seems very light, easy to use, inexpensive. But is it effective?

BTW, I've found similar bags that filter down to 0.5 microns on ebay.

[Walter Carrington]

It doesn't appear that any testing was done, so can he know it works as he claims? What per centage of each size does it filter out?

I would absolutely not trust this to filter out harmful micro organisms. It should work fine to filter out debris, but then follow it with a treatment that is known to work.

[Stephen Barber]

It appears that any testing done has been in recycling oil for biodiesel.

Would McD's french fry oil and water filter the same?

[Roger Caffin]

Joke.
About as trust-worthy as a snake-oil merchant.

Testing to 1 micron (which is NOT enough to handle bacteria) requires a serious bit of lab gear. If it has not been tested by a certified test lab then any claims are just … fraud.

Cheers

[Roleigh Martin]

Roger,

If you combined that filter with Aqua Mira tablets (which you'd want to put in the output container and wait 30 minutes), according to this CDC document at http://www.cdc.gov/ncidod/dpd/healthywater/factsheets/pdf/giardia.pdf because the filter in the video is 1 micron, supposedly doing both would mean you'd not have to wait the 4 hour situation to deal with parasites, right? What do you think about that dual use approach? Over the weekend, I tried the dual use approach of Aqua Mira tablets and a Aqua Mira Frontier Pro Filter but by day 2, the filter took 4 hours to do 2 liters of water, even with a brand new pre-filter.

[Walter Carrington]

Roleigh, The idea is good, but I doubt if this homemade filter will reliably do the job.

[Roleigh Martin]

Has anyone tried the 3 oz Pure Easy Camper's Micro-Ceramic Water Filter – see http://microceramicfilters.com/

Looks really interesting, it filters down to .1 micron, costs only $65, and weighs only 3 oz.

Technical Data:
Size of ceramic membrane's aperture: 0. 1 micron Output: Approx. 0.3 l/min (10 oz. per minute) Capacity: 2,000 liters (Each replaceable cartridge will filter up to 530 gallons depending on water quality) Weight: Approx. 88g (3 oz.) Dimensions: 13.8×5.7×2.8cm

I don't know if filter is replaceable – it also says "treats up to 2000 liters of water!" — I wonder if one has to buy another one each 2000 liters of water.

A negative review is here:
http://hotdogjam.wordpress.com/2009/05/20/water-filter-review/

I am looking for a better tested 1 micron at least filter similar to what is the thread focused filter is. I like the idea of something at the 1 micron level to allow fast flow but also when combined with 1/2 hour wait with the Aqua Mira tablets, has you covered for everything. I just don't like the 4 hour wait situation.

[Roger Caffin]

Hi Roleigh

Caution: I am not a biologist and my opinion is only that of a barely educated layman… But since you asked, herewith MY thoughts.

The four hazards are:
viruses: 0.01 micron
bacteria: 0.3 – 1 micron
protozoa: 3 – 20 micron
chemicals: farm, pollution, you name it, and not handled by any of this.

When water contains lots of organic matter whatever chemical you are using may be partly used up on 'dead' organic matter like tannins, bits of silt, moss, etc. So you may need to increase the amount you use, and predicting how much is 'not easy'. It can make the water taste quite yuk.

One solution to this, which also has some visual appeal, is to filter the water first with a coarse filter, as demonstrated on the video. I have even use a handkerchief at times … What you usually don't know is where the threshold of your coarse filter is, but you should assume that it could let even protozoa through, unless you have certified evidence to the contrary.

Now, the bag filter material used in the video is NOT rated for human/medical use. It may be rated at 1 micron, but the first problem is we don't know what that means. What I can tell you is that the rating does NOT mean that the filter will block everything below 1 micron: it won't. It is a statistical filter. It might block 90% of the materials below 1 micron, ON AVERAGE.

The second thing we don't know is whether every square millimetre of the fabric has the same effectiveness. It is entirely possible that there could be weak spots in the fabric, places where it only filters to 5 microns. The manufacturing process used does not guarantee perfect uniformity. It is not designed for that.

So what comes out of all this is that the filter should remove all 'large' organic matter, and probably most protozoa as well. It will not remove chemicals, viruses or bacteria, and it will possibly allow a small percentage of protozoa through. However, the concentration of protozoa in water is never large, and you need at least 10 cysts for Giardia to be a hazard anyhow, so that might make most water *effectively* protozoa-free.

That leaves you to treat the water with a chemical and wait maybe only 10 – 30 minutes, depending on the water temperature. I'll stick my neck out here and say that in most cases that would be safe enough. There are a couple of places where I know Giardia is a serious hazard, and in those places I would hesitate, but elsewhere it would seem pretty safe.

A thought worth considering is that I think the pleated filter in the Katadyn Hiker uses a paper membrane rather like this. I was sent a sample of the filter paper pleated but not made up into a filter, and it does look similar. I guess the manufacture and quality of such material has been progressing over the years.

OK, bottom line. Provided the filter material came from a reputable source! and genuinely was rated to 1 micron, I would probably be willing to trust the dual treatment approach (30 minutes) as described. It's what many have been doing for some time anyhow.

Second bottom line: It looks a whole lot cheaper than a commercial filter pump, I must say. BUT, it relies on user care to handle the filter and avoid cross-contamination. Beware of this: handle with care.

Cheers
PS: while I carry a Steripen, my wife and I have given up treating most water sources, especially small side-creeks.

[Roleigh Martin]

Thanks Roger, and thanks for the elaboration of the statistical average versus 100% filtering at 1 micron or less. I did find a commercial equivalent of the filter shown that is about $3.33 apiece.

http://www.plymouthwater.com/pdfs/310088%20BP-BPHE-BN%20Series.pdf

Has the technical information on the range of filters they give specs for. The one that interests me is the: Pentek BP-410-1 Bag Filter – it does say regarding water treatment: "WARNING: For drinking water applications, do not use with water that is microbiologically unsafe or of unknown quality without adequate disinfection before or after the system."

If you google this "Pentek BP-410-1 Bag Filter" you'll find it plenty abundant to order and try at that cost. I don't know the weight though. I think I'll order some at this low of a price.

Postscript: bummer, I can't find anyplace that takes orders under qty of 10, so lowest order cost is around $52. Forget it at that price.

PPS – I found by doing a search on ebay for "5 – 4"x8" 1 Micron Polyester Filter Bags Biodiesel " that you find something under $12. I've emailed him at ebay to see if he sells anything smaller, such as 4"x4" filters that are 1 micron.

[Stephen Barber]

Here's a single bag, similar to the video, but rated 0.5 microns:

http://cgi.ebay.com/0-5-1-2-Micron-16-Polyester-Filter-Bag-SVO-Biodiesel_W0QQitemZ250415404450QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item3a4debd5a2&_trksid=p3911.c0.m14&_trkparms=65%3A12|66%3A2|39%3A1|72%3A1205|240%3A1318|301%3A0|293%3A1|294%3A50

[Tad Englund]

Roger is correct- even the FDA approved and tested bag are not that good. Here is what the manufacturer states:

http://www.mcmaster.com/#filter-bags/=24w1y9
for their "Polypropylene felt bags are FDA compliant"
"Micron Ratings— Absolute-rated filter bags will retain at least 90% of particles of the specified micron size. All other bags will retain particles, but not to any percent efficiency. Often referred to as nominal rated. To achieve the desired filtration, select a bag with a micron size smaller than the particles you want to filter".

We don't know if his bags are even rated and even if he was lucky and found ones that are, I would like a little better then 90%- its the 10% that I always worry about.

I've been making Biodiesel for a several years now and 90% is great for what we do, Petro diesel from the pump isn't as clean as Bio, but we don't drink the stuff either.

The bag would make a very good, but very expensive pre-filter. I think it is back to the drawing board on this one.
We need to keep trying to find something better, keep up the good work.

[Roleigh Martin]

Tad, my concerns are limited. I will be treating the final container with Aqua Mira tablets for 30 minutes. I only want to ensure I don't have parasites, etc., in the water which a 1 micron plus filter shoudl deal with plus my trail I'm hiking is very incredibly clean water left untreated, it's the John Muir Trail. I probably could go the trail untreated but I want a 1 micron filter that won't clog and is not heavier than 2 oz preferably. Parasites are extremely rare in the water on that trail. Knowing this, what do you think of the 1/2 micron filters advertised acting as a pre-filter before the Aqua Mira tablets are used for 1/2 hour afterwards in the filtered water?

[Walter Carrington]

Filtering out 90% of everything below 1 micron is not very good. The Sawyer 0.1 micron filter is an absolute filter and filters out "removes 7 log (99.99999%) of all bacteria like salmonella, cholera, and E. coli. And 6 log (99.9999%) of all Protozoa such as Giardia and Cryptosporidium. You will find these removal rates to equal or exceed competitive options. EPA guidelines allow ten times more Protozoa left in the water than we allow." http://www.sawyerproducts.com/SP161.htm
According to this, EPA guidelines are 99.999% of protozoa removed.

"Parasites are extremely rare in the water on that trail." Has the water been tested??

[Tad Englund]

Roleigh, I would have no problem using the bag as a prefilter before using Aqua Mira. It is not a cheap option but far better the a coffee filter.
If you use the 5/1 bags they offer you will be doing a 2 stage prefilter, first at 5 microns then another at 1 micron.
According to Rogers numbers "protozoa: 3 – 20 micron" you will pick up most (90%) in the first stage and the rest are too large to make the second stage, all this is with a 90% accuracy, but the two stage process might up your percentages a little-
Using basic math you should get:
90% at the first stage, leaving a possible 10% missed. 90% of the remaining 10% is 9%. Adding the 90% and the 9% gives you 99%, not bad odds. I know this looks like Governmental math but it works for this argument.
It might be even better to use 2 layers (double bag) the 1 micron bags; it will greatly increase your odds of cleaning the protozoa. It would be a truer 99%.
You should be in good shape if you are dealing with the streams you describe.

I give no warranty to the above information and take no liability- if anyone gets the runs using this information it is not my fault- odds are you or someone you are with didn't wash their hands properly when doing their business.

[Roleigh Martin]

Actually the water has been tested many times in scientific journal articles, I'll try and find links to them later. I was at Midwest Mountaineering today and they had the Sawyer Inline .1 micro filter for making a gravity water filter system (1.8 oz weight) for $20 off, so I got one to see if it has a throughput acceptable (the aqua mira frontier pro filter is unacceptable for its throughput).

[Troy Ammons]

Gak,

People on ebay.

You can get a #1 size .5 micron bag filter here for $5.
7×16 or roughly 2 gallons.

http://www.filtersource.com/store/listCategoriesAndProducts.asp?idCategory=28

I think I am going to try one out.
My parents have a farm with a pond. Plenty of scummy ponds down here where I live too.
Think I might send in a filtered sample for a test – pre chorline treatment and see what it does.

The aqua mira is way too slow. Best for what it was designed asa backup emergency filter that fits on a bottle.

As far as the bag, it would make more sense to use it as a 1/2 micron prefilter before another inline highflow charcoal or other filter. Sort of like the bag inside a plastic sheet funnel bucket with a hose connection at the bottom.

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