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Researchers Develop "Tea Bag" Water Filter

samzenpus posted more than 3 years ago | from the steep-and-clean dept.

Science 119

cybernanga writes "A group of researchers in South Africa has developed a filter that can purify water straight from the bottle. The filter sits inside a tube fitted on top of a bottle and purifies water as it is poured on a cup. From the article: 'The designer behind the filter, Dr Eugene Cloete, from the Stellenbosch University in South Africa, says the filter is only as big as an ordinary tea bag. He says the product is cost-effective and easy to use. "We are coming in here at the fraction of the cost of anything else that is currently on the market," says Dr Cloete on BBC World Service.'"

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119 comments

Say it with me. (2, Funny)

jack2000 (1178961) | more than 3 years ago | (#33481368)

Molecular paper thin water filters.

Re:Say it with me. (2, Interesting)

Joce640k (829181) | more than 3 years ago | (#33481434)

The filter in the article is just an ordinary active carbon filter. This [ted.com] is waaay better.

Re:Say it with me. (3, Insightful)

TheLink (130905) | more than 3 years ago | (#33481516)

And waaaay more expensive?

I think their target market is "cheap", not "best".

The "lifesaver" water bottle may save lives, but a few very rich lives :).

This "tea bag" thing may not produce water as pure or safe, but might save many more lives if it really is cheaper, easy to use and practical.

FWIW the 100% way to prevent many trillions of human deaths is to kill all humans now, so be careful if you ever ask a super smart AI to minimize the long term total number of human deaths per year ;).

Re:Say it with me. (1)

Joce640k (829181) | more than 3 years ago | (#33481568)

I think you can buy them online for about $100 each. I bet you'd get a discount if you bought 1000.

If they can do 6000 liters of water then the price is probably competitive with teabags. I guess it depends on how people are organized and how they pay for them. Individuals won't have $100 to spend but governments and humanitarian programs will.

Re:Say it with me. (1)

Joce640k (829181) | more than 3 years ago | (#33481618)

My bad, the price I remembered was in pounds. They're $149 each and $300 for the jerrycan version: http://www.lifesaverusaonline.com/ [lifesaverusaonline.com]

Re:Say it with me. (1)

aliquis (678370) | more than 3 years ago | (#33482006)

At 300 $ / can useful for 6000 liters isn't it better to drill a well?

Best method however would most likely be:
a) kill their leaders.
b) confiscate all weapons.
c) give them 100% freedom and democracy.
d) have them ban import of foreign food.
e) give them generous (as in not greedy) small loans.

The rest they will solve themselves.

Point a and b isn't really necessary if part c is in place.

Re:Say it with me. (1, Insightful)

Anonymous Coward | more than 3 years ago | (#33482088)

You forgot the "build infrastructure" part. That's important for parts c and e to succeed.

And part d is likely inhumane.

(Do you really think it's that easy? Take democracy, add water, poof! It's like a libertarian's wet dream)

Re:Say it with me. (1)

aliquis (678370) | more than 3 years ago | (#33482678)

If they get anything working and some money I assume they can afford to build infrastructure at some point. I doubt it will just pop up from nowhere.

D isn't inhumane. Growing their own food would be more humane than depending on eventually getting hold of a surplus from the rest of the world, or not.

Re:Say it with me. (1)

korean.ian (1264578) | more than 3 years ago | (#33482212)

c) give them 100% freedom and democracy

This clearly hasn't worked - read Amy Chua's "World on Fire" for an explanation of why. Better still, but probably too dense for the average reader is Barrington Moore's "Social Origins of Dictatorship and Democracy".

Re:Say it with me. (4, Informative)

sjames (1099) | more than 3 years ago | (#33482704)

With those prices and 3rd world exchange rates, they'll never develop their economies! They'd be in perpetual debt for water bottles.

Even Britta costs a fraction of that, and, of course, chlorine bleach (as a pre-treatment to kill bacteria)is dirt cheap.

Meanwhile, a solar still can be made with a bucket, a plastic sheet, and some manual labor. Unlike a filter, it will continue to produce clean safe water year after year with no expendable. The construction technique is simple enough that adult supervised children can do it (and learn a science lesson in the process with an immediate application).

The developed world seems to have a bias against such solutions that don't make the 3rd world dependent on a continuous stream of "manna from heaven" in the form of manufactured goods. Part of that seems to be a bit of Marie Antoinette syndrome (just can't imagine a place where such cheap ubiquitous materials are expensive and rare). Part is that people imagine that accountant run businesses will lay off their drive for profit just a bit for the sake of humanitarian aid (they won't). Perhaps part because they might then start growing their own economy rather than becoming dirt cheap labor for our clothing industry.

Meanwhile, much of the problem will stop when the developed world kindly stops selling greedy warlords automatic weapons and all the ammo they can carry.

Re:Say it with me. (2, Interesting)

aliquis (678370) | more than 3 years ago | (#33481964)

I read that you can filter out e-coli or whatever common bacteria there was in water with a regular piece of cloth since the bacteria where grouped into bigger groups/particles.

Too lazy to try to find the magazine but maybe someone else know what I was supposed to talk about :D

Anyway, simple techniques can obviously be beneficial to, even if they won't solve all.

Re:Say it with me. (1)

fluffy99 (870997) | more than 3 years ago | (#33482370)

The filter in the article is just an ordinary active carbon filter. This [ted.com] is waaay better.

Cool piece of equipment. It's basically an RO filter. The pressure required for operation comes from the user pumping it up with an air pump. It's also small enough to take camping or on long hikes if you have a source of untrusted water nearby.

Re:Say it with me. (-1, Redundant)

Anonymous Coward | more than 3 years ago | (#33481624)

Molecular paper thin water filters.

Cue the conservativism jokes! (-1, Offtopic)

Anonymous Coward | more than 3 years ago | (#33481372)

Because Slashdot isn't in the least liberal slanted and does not make inappropriate sexual comments about Tea Partygoers.
 
I must be a conservative! Oh, wait, why am I not in church right now?

Re:Cue the conservativism jokes! (-1, Offtopic)

Anonymous Coward | more than 3 years ago | (#33481382)

First of all, way off topic.

Second of all, there are a lot of outspoken libertarians and republicans here

Third of all, if you don't like it... then leave.

Re:Cue the conservativism jokes! (3, Insightful)

blackraven14250 (902843) | more than 3 years ago | (#33481408)

and does not make inappropriate sexual comments about Tea Partygoers.

I thought Teabaggers were all for restoring the rights given by the constitution, regardless as to whether what's being said doesn't agree with their worldview?

Oh, sorry, I got caught up in theory and rhetoric.

Re:Cue the conservativism jokes! (1, Informative)

tuxgeek (872962) | more than 3 years ago | (#33481878)

I thought Teabaggers were all for restoring the rights given by the constitution

Wrong! Teabaggers are just another radical religeo/political movement that uses misinformation and outright lies to influence an ignorant public and gain members and momentum.

Recall the recent Beck rally on the steps of the Lincoln memorial.
WARNING SIGN: Beck states "religion and christianity have returned to America"
Same old christian coalition bullshit, different wrapper: "Separation of church and state is a luxury we can no longer afford"

"Separation of church and state" was put into our Constitution for a very good reason.
The teabaggers, Beck, and Palin out to give the illusion that their actions and motivations are faith based. The reality is that they are merely whores, willing to say and do anything for a buck, or the highest bidder, in the case of Beck and Palin

Disclaimer: I view all politicians and politics with ire and hate them all universally. Politics today is nothing short of organized crime.

Re:Cue the conservativism jokes! (1, Interesting)

Anonymous Coward | more than 3 years ago | (#33481932)

Yes, the whole point of the TEA party is to give other people a group to demonize so that they won't turn on people in power. In two years when the presidency is up again there will be a ton of conservatives spouting TEA party lines to get elected. The people who really believe in minimalistic government and a return to the constitution won't be found in the media or any mainstream political party. Everyone in the "middle" just wants more control over us. When you vote democrat or republican all you're doing is deciding which area of your life gets the increased government control. Extremism is the only way we as a nation will accomplish anything meaningful with our political situation. Our history of moderation and compromise in everything has brought us to where we are today--a political hellscape of unimaginable proportions.

Re:Cue the conservativism jokes! (1)

tuxgeek (872962) | more than 3 years ago | (#33482062)

Good post. You obviously read my disclaimer being you didn't flame me.
Too bad politics and life today is nothing short of stupidity in action.
I have little faith we will be able to free ourselves from the slime that encumbers us these days.
Those in power keep the masses in ignorance and darkness. Very effective method of control ..

Re:Cue the conservativism jokes! (-1, Troll)

tuxgeek (872962) | more than 3 years ago | (#33482026)

Ah yes, thanks for the troll mod
there's always some idiot tea bagging cocksucker to abuse the mod system

Re:Cue the conservativism jokes! (0)

Anonymous Coward | more than 3 years ago | (#33482220)

You may want to read up on the whole "Separation of Church and State" thing. It was to protect the churches from the state & not the other way around. While you're at it, you might also discover that some of the individual states had -official- churches.

-AC

Re:Cue the conservativism jokes! (1)

Vaphell (1489021) | more than 3 years ago | (#33484118)

not an USian here: if i am not mistaken Tea Party came to life as a result of grassroot efforts tied to the Ron Paul's presidential campaign of 2008 in rep party. Originally it was about returning to the strict constitutionalism - nothing more, nothing less.
Now it becomes a sad caricature of its former self as Palins and Becks, seeing the growing discontent among masses and TP's numbers, decided to steal the momentum of the movement. They hijacked it for their own goals, twisting the founding principles.

It's crystal clear that they unfortunately succeeded, because the father of the movement (Ron Paul) is not mentioned even once in this comment chain and the Tea Party is perceived as a bunch of primitive, thought free, religious loonies and Palin and Beck are called their leaders.

Re:Cue the conservativism jokes! (0, Troll)

Frosty Piss (770223) | more than 3 years ago | (#33481894)

I thought Teabaggers were all for restoring the rights given by the constitution, regardless as to whether what's being said doesn't agree with their worldview?

Some do, some don't. But mostly they like to dangle their ball sack in other people's faces.

Re:Cue the conservativism jokes! (1)

The Hatchet (1766306) | more than 3 years ago | (#33482546)

Not quite, they are in favor of restoring the rights they like from the constitution, and then removing the first, 14th, and any other ammendments they don't like, and placing a wonderful totalitarian theocracy on top of it, rewriting our history, fucking all of the poor people until they live in tent cities or just flat out die, eliminating our education system and making church mandatory, and eliminating all non-christian thinking, as according to them it is a lie from the pit of hell.

Also, they plan to do so by demonizing anything and everything that isn't so conservative it makes you want to kill yourself for supporting such bastards, and their sick cruel ways.

If you don't believe me just watch 15 minutes of Glenn Beck, right down everything he says and fact check it. If he gets even 1 point correct, I would be extremely surprised. The bastard gets off on telling blatant lies and fabricating elaborately false analogies to convince people that the otherwise ridiculous is not just plausible but if you deny it then you should be stoned to death.

Re:Cue the conservativism jokes! (1)

Vaphell (1489021) | more than 3 years ago | (#33483992)

i see a hole in your logic. How can there be a totalitarian state with a constitutionally limited government with majority of powers delegated to the states and with no public education brainwashing the masses? and how on earth the US survived the 19th century? There were no centralized education systems, no social security and no mandatory health insurance, no federal reserve micromanaging the economy.

Re:Cue the conservativism jokes! (1)

couchslug (175151) | more than 3 years ago | (#33483254)

"I thought Teabaggers were all for restoring the rights given by the constitution, regardless as to whether what's being said doesn't agree with their worldview?"

That would conflict with being the same Religious Right who Karl Rove so brilliantly exploited in the past. Rove is mostly out of the current game, but it's being played by very capable (and rich) people.

Unwitting and very earnest sock puppets are still sock puppets:

http://www.newyorker.com/reporting/2010/08/30/100830fa_fact_mayer [newyorker.com]

Re:Cue the conservativism jokes! (0)

Anonymous Coward | more than 3 years ago | (#33481456)

I must be a conservative! Oh, wait, why am I not in church right now?

Because you're a Seventh Day Adventist or a Jehovah's Witness?

Why are you so angry and cynical and have a chip on your shoulder? Oh, wait, you must be a Tea Partier.

Re:Cue the conservativism jokes! (1)

tuxgeek (872962) | more than 3 years ago | (#33482020)

Because you're a Seventh Day Adventist or a Jehovah's Witness?

Not sure what the Jehovah's Witness does for their worship or belief, with exception they are always there to knock on my door during dinner and hand me some crap declaring how much better the world is getting with each passing day.

Most Seventh Day Adventists however actually attend a traditional protestant church service. The difference is they observe the original "Seventh Day Sabbath" hence the name, as the Jewish faith does. There are NO similarities though between Seventh Day Adventists and Jehovah's Witness's. The only grouping together in that they are both faith based religions, and nothing more.

The idea of Sunday worship came out of the church of Rome and was implemented at their beginning to entice the roman sun worshiping "pagans" to attend their services along with the early Christian followers. It was a cash flow thing to maximize tithes and offerings.

Modern day protestantism observes the catholic sunday worship day even though in their beginning, during the reformation, they also observed the Saturday seventh day sabbath. Today there isn't much difference between the pagan rituals, superstitions, and beliefs of the roman church and modern protestantism.

Re:Cue the conservativism jokes! (2, Informative)

Anonymous Coward | more than 3 years ago | (#33482170)

There are NO similarities though between Seventh Day Adventists and Jehovah's Witness's.

They both worship the god of Abraham.

Re:Cue the conservativism jokes! (0)

Anonymous Coward | more than 3 years ago | (#33481526)

Well, forty minutes after posting and *you're* the only one who's brought it up. Perhaps you should consult a professional to determine why it is you spend your days obsessing about nutsacks.

Re:Cue the conservativism jokes! (0)

Anonymous Coward | more than 3 years ago | (#33481920)

...inappropriate sexual comments about Tea Partygoers

Most Tea Baggers are back-woods hicks with no teeth who fuck their daughters because mom ran off with a bear. And they generally have big hairy ball sacks. I've seen the video.

Re:Cue the conservativism jokes! (1)

Spatial (1235392) | more than 3 years ago | (#33482032)

Reality has a well known liberal bias.

Re:Cue the conservativism jokes! (0)

Anonymous Coward | more than 3 years ago | (#33482342)

Reality is a bloated, festering carcass lying half submerged in a ditch of green, scummy, stagnant water with maggots crawling on its dead milky eyes. A diseased mongrel comes along, sniffs at the carcass and, judging it ripe, tugs at the face of the carcass and pulls away a chunk of the cheek and nose and then scarfs it down. Not yet sated, the mutt lazily gorges itself some more until it has finally had its fill, then the beast turns, cocks it leg and pisses all over what remains of the face before it staggers away.

Wow! (1)

Bluesman (104513) | more than 3 years ago | (#33481394)

It's almost as if someone invented a disposable Brita water filter!

Re:Wow! (1)

aliquis (678370) | more than 3 years ago | (#33482048)

http://www.brita.com/intl/ [brita.com]

Funny how we (Sweden) are not on the list. Guess they know our tap water already is just fine (if you have your own well maybe less so.)

I've read about a few drops of Klorin (NaClO) is supposed to help to. Though not against chemicals or heavy metals and such.

Activated Charcoal (0)

vlm (69642) | more than 3 years ago | (#33481400)

Its just a bag of activated charcoal. Great at filtering out larger organics, not so good with microbial life forms and minerals.

I bought "cassette tape" sized bags of activated charcoal for my tropical fish tanks in the 80s. Glad to see the technology reinvented.

I'm not sure any amount of AC can protect fish from nearby rotenone spraying, then again its very hard to prove that without the AC bags my fish would not have died, its not like I was about to tempt fate. Thus plenty of opportunity for psuedo-science. Which MIGHT be where this product is headed, maybe.

Small filter (2, Insightful)

AnonymousClown (1788472) | more than 3 years ago | (#33481406)

"We cover the tea bag material with nano-structured fibres, and instead of tea inside the tea bag, we incorporate activated carbon.

"The function of the activated carbon is to remove most of the dangerous chemicals that you would find in water."

1. It would have to be one shot - I don't see that little bag filtering more than one bottle.Wouldn't that little bit of carbon be exhausted after 500ml?

2. The pour rate would have to be really slow so that the water stays in contact with the carbon long enough to absorb the toxic stuff. Five minutes+ for a cup of water??

3. It doesn't say anything about metals.

Re:Small filter (4, Insightful)

Joce640k (829181) | more than 3 years ago | (#33481450)

1. Yes, that's the point (might be a bit more than 500ml).

2. Not everybody is as impatient as you seem to be.

3. It's good old activated carbon again. There's plenty of info out there...

Re:Small filter (3, Insightful)

Culture20 (968837) | more than 3 years ago | (#33482340)

2. The pour rate would have to be really slow so that the water stays in contact with the carbon long enough to absorb the toxic stuff. Five minutes+ for a cup of water??

5 minutes for water versus running to the toilet every 5 minutes. Good trade.

The Clorox solution (1)

PolygamousRanchKid (1290638) | more than 3 years ago | (#33481418)

A doctor that I knew back in the '70s did volunteer work for the World Health Organization, and spent a lot of time in some god-awful places. He told me that they would use Clorox bleach to purify their water. One cap full for a bucket of water. It tasted terrible, but as for the alternative for an industrial scale case of diarrhea . . . it was the lesser of two evils.

So I wonder how cheap this gadget is compared to Clorox?

Re:The Clorox solution (3, Insightful)

Freddybear (1805256) | more than 3 years ago | (#33481440)

The charcoal filter would be good to use *after* you sanitized the water with chlorine bleach. Kill off the biologicals and then get rid of the chlorine taste.

Re:The Clorox solution (2, Informative)

UnknowingFool (672806) | more than 3 years ago | (#33481472)

Yes but that solution doesn't remove any contaminants in the water; it only kills microbes.

Re:The Clorox solution (0)

Anonymous Coward | more than 3 years ago | (#33481504)

You know, this is just one more stupid solution to a very big problem. For the past fifty years, we've been throwing money at those poor countries, by buying food, and water and generally pouring more and more money into temporary solution. What they need, is not teabags to filter water, they need a sewage system, they need an infrastructure to deliver clean purified water. You know, just like that saying you feed a man, you help him for a day, you teach him to fish, you helped him for a lifetime.

Re:The Clorox solution (0)

Anonymous Coward | more than 3 years ago | (#33481532)

...they need a sewage system...you teach him to fish, you help him for a lifetime.

You build him a sewage system, you teach him how to...er, how to...crap?

Re:The Clorox solution (0)

Anonymous Coward | more than 3 years ago | (#33481550)

microbes by and large are the problem, so bleach does fix the problem. However, to answer your question, the problem with infrastructure improvements is that the locals haee to give a shit for infrastructure to be built. It's a lot more effective to spend a million dollars on mosquito nnets then it is to spend several million dollars preparing to build a sewer system that will get nowhere in the retarded local berequcracy. In short, Africa is fucked.Hell, the shining light of africa, S.A. is about to have a civil war and turn itself into Zim. Kenya was doing well until they had an election and proceded to burn the country.

Re:The Clorox solution (1)

boxwood (1742976) | more than 3 years ago | (#33481656)

Also it doesn't make sense to spend millions on infrastructure when it will be destroyed in the next civil war... which will be next year.

Maybe we shouldn't be supplying warlords with weapons and ammunition... Oh we can't do that because then Communists/Islamists/Eurasia/Eastasia might take over the country!

Re:The Clorox solution (1)

Hognoxious (631665) | more than 3 years ago | (#33481770)

I think the Chinese have already bought most of Africa anyway.

Re:The Clorox solution (1)

aliquis (678370) | more than 3 years ago | (#33482114)

I think the Chinese have already bought most of Africa anyway.

Yeah, stupid China! Weird how financial and constructional help seem to be more popular than militarily one.

Re:The Clorox solution (1)

aliquis (678370) | more than 3 years ago | (#33482086)

Kenya was doing well until they had an election and proceded to burn the country.

Kinda like when you elected Bush as president? Twice! .. :D

Re:The Clorox solution (1)

Abcd1234 (188840) | more than 3 years ago | (#33481698)

Actually, what they really need is the west to stop subsidizing farm production, thus depressing world market prices. They need the west to stop dumping free food into their economies, thus depressing local market prices. They need a level playing field where they can finally fucking compete. Maybe then they'll be able to invest in improved infrastructure and other necessities.

Re:The Clorox solution (1)

Joce640k (829181) | more than 3 years ago | (#33481806)

Government corruption is so rampant that pretty trying to organize pretty much anything on a large scale will fail. The only way to help is to get in there where the normal people live and solve their daily problems (water, food...). Things will only improve when they've got some free time left over after the daily subsistence tasks for other stuff. Free time equals education and building.

Re:The Clorox solution (1)

mspohr (589790) | more than 3 years ago | (#33482112)

I thought you were describing the USA here...

"Government corruption is so rampant that pretty trying to organize pretty much anything on a large scale will fail."

... This of course refers to large corporations controlling government to preserve their monopoly positions and preventing individual or small business success.

"The only way to help is to get in there where the normal people live and solve their daily problems (water, food...). " ... It is good that we have private charities to help people with food and shelter in the USA.

"Things will only improve when they've got some free time left over after the daily subsistence tasks for other stuff. Free time equals education and building."... People are too busy trying to earn a living (if they can find a job) to get a good education or try to build up something.

Re:The Clorox solution (1)

Abcd1234 (188840) | more than 3 years ago | (#33482514)

Government corruption is so rampant that pretty trying to organize pretty much anything on a large scale will fail.

Correct. Which is why you need a fair market in which communities and individuals can actually participate, such that wealth can be injected at the bottom of the socioeconomic ladder, rather than relying on handouts that are funneled through corrupt regimes.

Things will only improve when they've got some free time left over after the daily subsistence tasks for other stuff. Free time equals education and building.

Yup, absolutely. But these people *can't* do anything but subsistence farm because the world markets are so heavily tilted in favour of the western world. How the hell can you expect them to get free time if they can't even earn a fair dollar for their work?

Re:The Clorox solution (1)

aliquis (678370) | more than 3 years ago | (#33482124)

Of course we should subsidize it since that keeps us alive if things goes bad. If no-one wants to grow an excess of crops you're screwed if it does.

That's not the issue. The issue is that they don't. And that the excess is dumped there for prices they can't compete with.

But food is just one thing.

Re:The Clorox solution (1)

aliquis (678370) | more than 3 years ago | (#33482066)

Yeah but China has started fixing that.

And they generate jobs for themselves while doing so.

Plus they get more people to sell and buy goods from.

Also are the west really "buying food for them" as much as "dumping food into their market for cheap because we got plenty to not risk a starvation, too bad they don't once the crop season goes bad in the western world"?

Re:The Clorox solution (2, Interesting)

Scrameustache (459504) | more than 3 years ago | (#33481606)

Yes but that solution doesn't remove any contaminants in the water; it only kills microbes.

The bleach will also break apart many kinds of contaminants, it won't remove heavy metals and whatnot, but I think bleach can break poisons.

Clorox was "different" in the 1970s ... (2, Informative)

perpenso (1613749) | more than 3 years ago | (#33481734)

Be very careful with the clorox method. The clorox product line is quite different today and you probably do not want to use the versions with stain removers and other additives for water purification. From the clorox website:
"Disinfection of Drinking Water (Potable)
... Only Clorox Regular-Bleach, of all the bleaches mentioned on this website, is approved for sanitization and disinfection. ..."

Also, does this approach work from bacteria to virus to cryptosporidium? My understanding is that the old school iodine tablets don't work on the later and that the military and NGOs have moved to chlorine dioxide based tablets. Much better tasting too. The caveat is that it takes something like 4 hours to kill the crypto compared to something like 15 to 30 minutes for the lesser "bugs". Being chlorine based maybe clorox could work with crypto but they don't seem to offer concentration or time guidelines. Perhaps they are just addressing North American concerns, maybe their sites for other parts of the world offer advice?

Clorox not effective against cryptosporidium? (2, Informative)

perpenso (1613749) | more than 3 years ago | (#33481762)

Answering my own question:
"Results of the present study show for the first time that C. parvum oocysts exposed to undiluted laundry bleach for as long as 120 min are infectious for animals. Although bleach is widely used as a bacterial and viral disinfectant, the present findings indicate that under practical conditions it is not an effective disinfectant for C. parvum oocysts."
http://aem.asm.org/cgi/reprint/61/2/844.pdf [asm.org]

Re:Clorox not effective against cryptosporidium? (1)

Lehk228 (705449) | more than 3 years ago | (#33481904)

looks like a couple days in the sun will kill them off, so treat the water for a week in clear non-UV blocking containers, then bleach, then let sit for 24 hours and you should be good to go

Re:Clorox was "different" in the 1970s ... (1)

bcrowell (177657) | more than 3 years ago | (#33482364)

Also, does this approach work from bacteria to virus to cryptosporidium? My understanding is that the old school iodine tablets don't work on the later and that the military and NGOs have moved to chlorine dioxide based tablets. Much better tasting too. The caveat is that it takes something like 4 hours to kill the crypto compared to something like 15 to 30 minutes for the lesser "bugs".

There are basically two different types of treatment that work on two different types of microorganisms. Iodine and other halogens work great on viruses and bacteria, but not on protozoa such as cryptosporidium and giardia. Filters work great on protozoa (which are physically large) but not on viruses (which are physically small).

Although ClO2 tablets do work on protozoa, they're really not optimal. As you've noted, they take hours to work, which means that many people will run out of patience and drink the water before the protozoa are all dead; the best treatment method in the world won't do any good if users don't find it convenient to use it properly. The other issue with ClO2 tablets is cost. Here in the US, where I buy them for backpacking, they are expensive enough that I consider them a significant cost -- and my yearly income is probably a hundred times greater than people in the areas being targeted with this teabag technology.

So if you want low cost combined with good effectiveness, halogens plus filtering really is the one-two punch you want. It sounds like this filter is designed to be used in areas where the water supply is chlorinated, so people who use the filter are basically getting rid of the chlorine taste, killing protozoa, and filtering out some harmful chemicals.

Re:The Clorox solution (1)

vlm (69642) | more than 3 years ago | (#33481754)

One cap full for a bucket of water. It tasted terrible,

The water treatment guys screwed up. Chlorinated water shouldn't taste awful after purification, certainly not even as bad as swimming pool water. The "art" of chlorination is to use just enough hypochlorite to oxidize all the microbial life, anything over and above that is wasting supplies, aim for the "faintest taste of chlorine". Also you can aerate the water, just pouring it from cup to cup for a few minutes will help noticeably. Storing treated water after Cl dissipates will allow whatever was growing in there to start growing again, so theres little point in stockpiling treated water. The point I'm making is, assuming the water treatment dudes were not totally incompetent (which is possible despite 3rd world conditions), a canteen full of dog pee would be perfectly safe to drink after treatment, but won't taste good. So there's some reason other than Cl2 content that the water tastes horrible, and frankly you probably don't want to know why. Dead animal carcass upstream, manure runoff/sewage leakage upstream, dead fish suction-stuck to intake grates, etc. The foulest "treated" water seems to come from swamps full of decaying everything.

Now you want foul tasting treated water, try iodine purified water. That stuff is foul, but iodine stores better than chlorine compounds, more stable. Great for 3rd world. All halogens taste / smell pretty much the same and your Dr buddy might not have known better.

Re:The Clorox solution (1)

aliquis (678370) | more than 3 years ago | (#33482060)

I think the chlorine taste may disappear by itself if you let the water sit for long enough (with ventilation that is)

No?

Re:The Clorox solution (1)

phantomfive (622387) | more than 3 years ago | (#33482218)

As someone who also lived in some god-aweful places, I'll tell you one cap for a bucket of water is going to burn your throat (unless it's a really big bucket). Usually you want no more than 8 drops of chlorine per gallon of water.

Re:The Clorox solution (1)

Weedhopper (168515) | more than 3 years ago | (#33482800)

One of the hats I wear is that of an emergency water engineer in disasters, conflicts and other public health emergencies. I've worked all over Africa, SE Asia and now the Caribbean.

One cap of chlorox is beyond excessive and detrimental to anyone who would drink it. Bleach to chlorinate water is okay in an truly urgent situation but is not an idea solution.

Your question implies that your understanding is that filtering versus chlorination are processes that are exclusive of the other. In almost every situation, to minimize the amount of chlorine used, the water should first be filtered, then chlorinated. Otherwise, there's just too much stuff in the water that consumes the chlorine before it can get to work in oxidizing anything organic.

This is the same basic process used in most conventional water treatment facilities the world over, from municipal plants to smaller scale portable plants for refugee/IDP camps.

These have been around (1, Interesting)

Anonymous Coward | more than 3 years ago | (#33481462)

http://www.campmor.com/aquamira-water-bottle-filter-kit.shtml?source=CI&ci_src=14110944&ci_sku=25674WC

For example, is what I have had for years to take backpacking. And they aren't even expensive. I guess I don't see how this is innovative.

Re:These have been around (1)

twidarkling (1537077) | more than 3 years ago | (#33481914)

Well, it can go in *any* bottle, rather than needing a special bottle, meaning that you don't need to worry about losing your special bottle in areas where social stability is ephemeral at best. So a filter that can go in any old bottle you have laying around, and can be made cheaply, and is small, yes, is innovative. Sometimes it's not about function, it's about form.

They should get a patent... (0)

Anonymous Coward | more than 3 years ago | (#33481494)

a filter that can purify water straight from the bottle?

I could only find six other products that sound similar.

http://coffeetea.about.com/od/water/tp/waterbottles.htm

Tea Bagging? (0)

Anonymous Coward | more than 3 years ago | (#33481498)

I don't understand how Tea Bagging cleans water.

Copper water still (0)

Anonymous Coward | more than 3 years ago | (#33481518)

I still do not understand the dilemma behind water purification on a small scale.

I know activated carbon is great at filtering out the stuff you can't see, and sand is great at filtering out the stuff you can see, but what about a simple water still? Once the crud has been removed by sand (no lack of abundance there), couldn't all the microbial stuff / viruses / bacteria be killed while the water is boiling? Not to mention the fact that extremely pure water can be made this way. (I used to be responsible for distilling water as a chem undergrad).

I suppose the only problems would be the fuel (wood and other biofuel consumption would suddenly take a hike), training (operating the still), and maintenance (cleaning the crud out). But this solution seems much easier than transporting activated carbon around in a tea bag...

On a large scale, a medium sized still could produce enough potable water for at least 100 people if operated full time.

Re:Copper water still (2, Interesting)

Scrameustache (459504) | more than 3 years ago | (#33481626)

I suppose the only problems would be the fuel (wood and other biofuel consumption would suddenly take a hike), training (operating the still), and maintenance (cleaning the crud out).

Materials, portability, scalability, possibility of being used by small children, safety of use, etc.

They're looking for something they can airdrop on refugees.

Re:Copper water still (1)

Iskender (1040286) | more than 3 years ago | (#33481838)

Another advantage over boiling water that I can think of is that these filters cannot (easily) be used for anything else. If you need firewood/fuel to sterilize your water, you might face the choice of either the meat or the water being raw when you have limited fuel (or more likely porridge of some sort will take the fuel, since meat is a luxury). This filter makes the water pure, making the fuel available for other things by default.

do some research (0)

Anonymous Coward | more than 3 years ago | (#33482232)

This sort of technology is my bailiwick. There are any number of cheap to free solar devices out there that can substitute for using wood or dung to heat water to boiling. Basically you set up a compounded reflector, you can use anything, scrap sheet metal, etc. You can also solar distill the water using nothing more than a sheet of plastic. Solar works remarkably well in hot areas like Africa.

This is some of the tech that should come stock installed in those OLPC devices going to the third world, how to purify water using local scrounged materials, how to cook without burning stuff, etc. The dudes in the developed world are just fixated on selling stuff, if they switched to pure education, it would help more people at much lower costs. They want to sell devices, gadgets, etc to governments, like this charcoal tea bag thing. The kids laptop is an exception, it is actually useful, because you can store so much text files on it that is practical information, simple line drawings/cartoons would work, you wouldn't even need to be able to read then to get useful information from it.

Yeah, but does it work? (1)

Angst Badger (8636) | more than 3 years ago | (#33481630)

I don't know about the "nano-fibers", though I've gotten to be suspicious of "nano" as a meaningless marketing term like "cyber" was ten years ago, but activated carbon's efficacy as a filter depends on how long it is kept in contact with the water, which is why those pricey tap filters are generally a waste of money. It's probably better than nothing if you're drinking water out of a stream or lake, but I'd be genuinely surprised if it was much better than nothing.

strange brew that's also good for you (-1, Offtopic)

Anonymous Coward | more than 3 years ago | (#33481634)

That would be home made Kombucha.

Oh, no... (-1, Offtopic)

Anonymous Coward | more than 3 years ago | (#33481648)

Do not drink the T-Bagger's water!

"tea bag" means single use (2, Informative)

Anonymous Coward | more than 3 years ago | (#33481722)

Better article [scienceinafrica.co.za] says:

  The inside of the tea bag material is coated with a thin film of biocides encapsulated within minute nanofibres, which kills all disease-causing microbes.
  The bag is filled not with tea leaves but with active carbon granules that remove all harmful chemicals, for instance endocrine disruptors.
  Each "tea bag" filter can clean one litre of the most polluted water to the point where it is 100% safe to drink.
  Once used, the bag is thrown away, and a new one is inserted into the bottle neck.

Sounds good, but doesn't remove fine particulates or heavy metals, so you have to prefilter and chose your water source wisely (check arsenic contamination maps....)

Tea bag, except you don't use it like one (1, Insightful)

noidentity (188756) | more than 3 years ago | (#33481794)

Calling it a "tea bag" filter even though you don't use it like one (that is, place it in cup and let it sit for a while) is misleading. Should we call it a "USB thumb drive" water filter just because it's a similar size?

my BS detector went wild (4, Insightful)

frovingslosh (582462) | more than 3 years ago | (#33481886)

Not only is there the dubious claim that this will make water safe, and the implication that it is somehow different from other activated charcoal filters already made, but they stress how cheap or affordable it is, without ever giving any indication of a price. When someone tells you that something is inexpensive but doesn't want to tell you how much it will cost in any quantity, it will not be inexpensive.

Just how little does it cost? (1)

DerekLyons (302214) | more than 3 years ago | (#33481956)

"Half the cost of anything else out there" is very nice, but doesn't tell us much. Wandering around the web, I find the lowest (retail) cost to be around $.50/gallon for single packaged filters. (Which will obviously be considerably lower in bulk and/or multi-packaged.)

can I get a few larger ones? (1)

josepha48 (13953) | more than 3 years ago | (#33482188)

Something like this may be useful in aquariums when doing water changes if it could purify a few gallons of water and was cost effective.

I wonder if a similar principal could be used to purify water after an oil spill?

What else is new? (2, Informative)

reboot246 (623534) | more than 3 years ago | (#33483418)

Inexpensive filter straws have been around for years. I don't see how this is that much better. There was nothing in the article about price or effectiveness of the filter itself. All we have is the designer's opinion, and of course he's naturally going to praise his own invention.

But can one drink it? (0)

Anonymous Coward | more than 3 years ago | (#33483430)

I'd rather pour it IN a cup rather than just on one.

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