NASA Testing Breakthrough In Water Safety

Jerry James Stone writes "NASA and University of Utah chemists are developing advanced tech for testing the drinkability of water. The process just began a six-month run aboard the International Space Station. Water will be sampled either from the Space Station's or Shuttle's galley using a syringe. It is then forced through a chemically-imbued membrane, which changes color based on toxicity. The process itself will take about two minutes. It checks drinking water for iodine and silver, which are used to kill unwanted microbes."

Comments

Water Safety?

[SultanCemil]

How does checking for iodine and silver check for water safety? Also - proofreading would be nice - "which are to used kill..."? My god what do we pay editors for?

Re:Water Safety?

[Jurily]

I believe the procedure is as follows:

1. Get someone to drink before you.
2. Wait for them to die.

Re:Water Safety?

[Zantac69]

Its a pretty common test in drinking water plants to do a "residual" test. In the US, they normally check for residual chlorine in the water as it leave the drinking water plant - as residual chlorine = no bacteria (for the most part). They also send inspectors out periodically and actually test the water at the 'end of the line' to ensure there is a chlorine residual. On the space station/shuttle, they iodine and silver are easier to handle than chlorine and are used in combination to disinfect the water...so a residual of both should mean that any bacteria/viruses have been removed. Of course this does not address the removal of soluble organics and other contaminants...but those are a bit easier to remove than critters.

Overstated much?

[MadAnalyst]

The device checks for disinfectant (Ag or I). That is neat and all, but I wouldn't go for a "breakthrough in water safety." Sure, disinfectant means fewer bugs in the water. I won't say that isn't one good indicator of safer drinking water. But there is a host of atomic and molecular toxins that the device does nothing about. The EPA regulates for about 20 different things, bacteria being only a small part of it.

Re:Overstated much?

[Chrisq]

My guess is that it addresses a specific concern on the space station. Someone has determined that there is a single point of failure that could leave unsafe residual amounts of treatment chemicals in the water. So this is a breakthrough but only for people with a very specific problem.

It checks Iodine and Silver content?

[lordandmaker]

So it's less a test of it's drinkability as one of whether it's yet been processed into drinkable water?

I was hoping for something that'd be useful to people in remote places who want to drink out of a river. I know the article mentions spin-offs for bangladesh.

Re:It checks Iodine and Silver content?

[clone53421]

The test won't show whether the sieve is working, it'll just show whether you put the right number of iodine droplets in your bucket of filtered river water. Yeah, this is about as innovative as those paper strips you use to check the chlorine level in your pool.

Re:Bah...

[Whalou]

It might not be a good indicator if your neighbor is named Schrödinger.

Re:Bah...

[Hognoxious]

You have to do the test 9 times to be really sure.

drinkability of water?

[rossdee]

So when NASA finally gets to Mars, they'll be able to test the water in the (chinese built) hotel and see if iits fit to drink.

Bad article, !toxicity

[clone53421]

They aren't testing toxicity, they're testing for effective disinfection (by ensuring there is the correct residual disinfectant remaining in the water). That's pretty uninteresting, actually. It's standard practice to test for a disinfection residual in the water treatment industry.

Common disinfectants are chlorine (either gaseous or in hypochlorites, e.g. sodium hypochlorite = liquid bleach, or calcium hypochlorite which is in the form of solid granules or tablets), chloramines (a chlorine/ammonia compound), ozone, and ultraviolet. Ultraviolet, of course, is a one-time hit and leaves no residual disinfecting agent in the water. Ozone dissipates quite rapidly, so the residual is gone in a short matter of time. Chlorine dissipates over the course of several days, while chloramines stay in the water for several weeks. Large water systems typically need a disinfectant which will stay in the water for several days or weeks, because it takes that long for the water to travel from the treatment plant out through the piping system to the edges of the distribution region. You have to have an adequate disinfectant residual even at the edges of your system in order to prevent microbial growth inside your pipes.

Frankly, I'm very not-impressed with TFA. This is somewhat better, it at least explains the disinfection process and why they need to test for these two substances (iodine and silver):

NASA uses iodine as a disinfectant on U.S. space crafts, and Russians use pure-silver nanoparticles that at low levels are non-toxic, but it's a balancing act. If the levels of iodine and silver in the water are too low, microbes will grow, Porter said. Levels of iodine that are too high result in bad-tasting water that the astronauts will not drink, putting them at risk for dehydration. A long-term effect of drinking an excess of iodine is the possibility of developing thyroid problems. Excess levels of silver can permanently turn the skin a grayish-blue color.

Of course, if you really want the low-down on the process, you get it from NASA's website...