Water Filtration With a Tree Branch

Taco Cowboy writes "Dirty water is a major cause of mortality in the developing world. 'The most common water-borne pathogens are bacteria (e.g. Escherichia coli, Salmonella typhi, Vibrio cholerae), viruses (e.g. adenoviruses, enteroviruses, hepatitis, rotavirus), and protozoa (e.g. giardia). These pathogens cause child mortality and also contribute to malnutrition and stunted growth of children.' People have been working on engineering cheaper and cheaper filtration systems for years, but now a group of researchers has found a promising and simple solution: a tree branch. 'Approximately 3 cm^3 of sapwood can filter water at the rate of several liters per day, sufficient to meet the clean drinking water needs of one person.' 'Before experimenting with contaminated water, the group used water mixed with red ink particles ranging from 70 to 500 nanometers in size. After all the liquid passed through, the researchers sliced the sapwood in half lengthwise, and observed that much of the red dye was contained within the very top layers of the wood, while the filtrate, or filtered water, was clear. This experiment showed that sapwood is naturally able to filter out particles bigger than about 70 nanometers.' The team tested E. coli-contaminated water, and the branch was able to filter out 99 percent of the bacterial cells."

Comments

Re:Take That, Capitalists!

[Flatwater]

Filtering out "99%" of harmful bacteria may be like filtering out 99% of bullets fired at you....

Re:First time?

[i kan reed]

Ideas can be publicized, studied in more detail, or put to good use, without being truly new.

Wooden chopping boards.

[Jason Pollock]

Trees are great at dealing with bacteria.

We soon found that disease bacteria such as these were not recoverable from wooden surfaces in a short time after they were applied, unless very large numbers were used. New plastic surfaces allowed the bacteria to persist, but were easily cleaned and disinfected. However, wooden boards that had been used and had many knife cuts acted almost the same as new wood, whereas plastic surfaces that were knife-scarred were impossible to clean and disinfect manually, especially when food residues such as chicken fat were present.

http://faculty.vetmed.ucdavis....

Re:Take That, Capitalists!

[CanHasDIY]

Filtering out "99%" of harmful bacteria may be like filtering out 99% of bullets fired at you....

So, I take it you're not a fan of Lysol or Purell?

What a silly thing to say; as if not filtering 99% of something harmful is a better idea...

Somebody Probably Thought of That

[Anonymous Coward]

"Somebody probably thought of that" is more likely to be untrue than true. You probably are the first person to think of that. And even if you aren't you might be the first person to act on the idea. And even if you aren't you might be the first person to succeed where others have failed. And even if you aren't, you might learn something. So don't ever say that, "somebody probably thought of that."

Filtering water through wafers of wood is not obvious to me. I do engineering for a living. If you are wondering why no one ever discovered something before, go back to paragraph one and repeat.

Re:Somebody Probably Thought of That

[K. S. Kyosuke]

It *is* obvious - after a fashion - since plants are generally doing just that; i.e., they use their root systems and cappilaries to absorb water including some impurities up to a certain size. The issue of "can we cut away a part of a plant tissue and filter water through it?" is probably more of a quantitative nature, rather than qualitative. As in, what is the filtering capacity? Does it clog? If it does, how often does it need to be changed? Does it rot? If so, how often does it need to be changed? The qualitative issues here seem to be "given that we're killing the plant, how does it affect the filtration process?" and "what preparation techniques can we employ to increase the practicality?". It's not that we don't have any filtration media, it's about how our knowledge and manufacturing processes make the individual filtration media more or less practical.

Re:First time?

[Anonymous Coward]

If this is true, then this is a really profound discovery that could help millions of people.

What I'm wondering, is why no other society, that we know of, has discovered this low-tech, yet seemingly incredibly useful thing previously?

Maybe because all of the other materials and equipment required to make it work.

You mean like some sort of cutting implement to cut down the branch?

I think the hatchet was invented at least 10 years ago?

Re:First time?

[Em Adespoton]

If this is true, then this is a really profound discovery that could help millions of people.

What I'm wondering, is why no other society, that we know of, has discovered this low-tech, yet seemingly incredibly useful thing previously?

Well, I learned this technique as part of my Aboriginal American studies when I was growing up -- I think it's more likely that our western culture has "lost" this knowledge than that nobody has discovered it before.

Re:First time?

[K. S. Kyosuke]

1) Someone mentions a new discovery.
2) Find a passage in the Bible containing the (rather common) keywords, without actually using your brain to check that the passage has identical informational value.
3) ???
4) Prophet!