Oct. 17, 2008 -- Ask Bob Bagdigian for a drink of water and you may get more than you bargained for. He's been working on a system that gives new life to urine and perspiration and it's ready for prime time aboard the International Space Station this fall.
Bagdigian, the project manager for NASA's Regenerative Environmental Control and Life Support System, explains to Discovery News' Irene Klotz why he still has friends.
IK: So, how long have you been working on this?
BB: In some fashion, since I first hired on at Marshall back in '85. Back then, we were doing early technology development and trade studies to decide the best way of making this type of water recovery process. That activity evolved and in 1998 we were authorized to begin producing the flight systems that would go to the ISS.
IK: Is there anything like this on Earth?
BB: Our system is a combination of technologies, some of which are used in many applications on the Earth, some of which are unique in the way we've integrated them for space station applications.
IK: Any companies interested in developing this for use on Earth?
BB: There have been some commercial applications of specific parts of the system. One of the things we do is add iodine to the final water for microbial control and that technique has been used in some other non-NASA applications, one of which was a humanitarian effort ... to purify water which was sent to northern Iraq and Kurdish villages.
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IK: Oh, how long ago was that?
BB: Two or three years ago. It was done by a charity, Concern for Kids.
IK: So, this system is headed to the space station, which next year is supposed to have its crew size doubled from three to six. Can't the Russian system currently in use be modified for six people?
BB: The Russians do have some capability dating back to some of the earlier space stations, Salyut and Mir, but their system is limited to collecting water out of the cabin atmosphere. When people live in a closed environment, the release water is in the form of perspiration and respiration. That water is condensed out of the air-conditioning unit and the Russians have been operating a condensate water processor. They take the humidity condensate and reprocess it. Because it is only processing humidity condensate, it does not have the capability to process urine, like our system does. Our system processes a combination of urine and humidity condensate.
IK: How much water can be reclaimed?
BB: We're expecting our ISS system to be called up to process a little less than 50 pounds of water per day, which is about six gallons a day. That in combination with the Russian system can support a crew of six.
IK: Is the system completely self-sustaining?
BB: Our system can recover about 92 percent of the water available to us in the combined wastewater that we get. We put the urine through a distillation process separate from the other wastewater we get and we can recover about 85 percent of the water. We take that and combine it with the humidity, which we can recover 100 percent, and that works out to be on the average a low-90 percent recovery efficiency overall.
IK: How much does it cost, like if I wanted to put one in my house?
BB: You probably wouldn't want to put one in your house just yet, get some economies of scale. It's about $250 million and that includes an oxygen generation system already aboard the ISS.
IK: So until the gas price gets really, really expensive, it's probably cheaper for me to continue to go to the grocery store and get my water?
BB: Get it out of your tap.
IK: Water from my tap has a very strong chlorine smell. I think I'd rather drink urine than chlorine. It seems a lot healthier.
BB: Actually we did blind taste tests of the water we were able to produce from urine and humidity condensate and tap water that had been put through a similar kind of treatment process. Nobody had any strong objections to the water. The most common comment we got back related to the faint taste of iodine was in the water. It gives it what people described as a medicinal kind of taste.
IK: Do you notice a difference?
BB: I taste the iodine, but other than that it is just as refreshing as any other kind of water. I've got some in my 'frig. It tastes fine to me.
IK: When you offer that to people do you tell them where it came from?
BB: Yeah, usually.
IK: After or before they drink?
BB: They're usually interested to know it beforehand.
IK: Have you ever given it to someone and told them afterward what they're drinking?
BB: No.
IK: Really? You're a really nice man, aren't you?
BB: Well, I usually like to see if knowing where it comes from if they're still willing to go ahead and drink it.
IK: And do they? What's been the response?
BB: Yes, people have a natural curiosity about it.
IK: How does this system work? How does an astronauts' urine go through the process of becoming water for his oatmeal in the morning?
BB: Urine is collected and temporarily stored in storage tanks and then it goes through a process called vapor compression distillation. That's just a long word for a boiling process in which we generate a relatively purified steam from the urine. We do that in a distillation process that we had to optimize for operation in microgravity. In microgravity, the vapor and the liquid tend to not separate like they do on Earth. The distillation process actually rotates to create some gravitation forces within the fluid that then allow the vapor and the liquid to separate. That steam that we generate is then obviously much cleaner than the urine from which it was derived, but still is not nearly clean enough for astronauts to drink. So we then combine that distillate with the humidity condensate that's collected from the air conditioning systems of the space station and that combined mix then flows though the remainder of our system.
There are a number of steps. The first thing we do is remove any residual gas or trapped air from the water. Doing that in microgravity requires a unique step. We use a rotary separator again to induce gravitation forces that will separate that gas from the liquid. From there, we then pass the water through a relatively standard filtration device that will remove a solid particulate matter from the water -- hair, lint, skin cells -- relatively minor things, but stuff that still needs to be taken out nonetheless.
Next the water goes though multi-filtration beds -- our name for some treatment beds that include a combination of filtration media, much like you can find in commercial-off-the-shelf devices that are sold to treat tap water at home, things like activated carbon and ion-exchange resins. The water that comes out is pretty clean but there are still some trace organic material contaminants in the water, so the next thing we do is process the water through a catalytic oxidation process. That's just a fancy name for a processor where we add oxygen, we heat the water up to a very high temperature, we run it over a catalyst and under those conditions those trace organic contaminants are converted to other chemical forms that make them subsequently removable by traditional ion exchange resins that we have downstream.
We run the water through an ion exchange bed, add iodine to the water and at that point it is now potable water, meets our water quality requirement. The water is stored in a tank and is available for use whenever the crewmembers have a need.
IK: How long does it take for all that to happen?
BB: We can process a full days worth of wastewater in less than 24 hours, so today's drinking water was yesterday's waste.
IK: What's your background?
BB: I'm a chemical engineer by training.
IK: So in your wildest dreams, did you one day imagine that you'd be recycling pee?
BB: No, I certainly didn't imagine that. When I was a kid I was always kind of fascinated with the space program, built rockets and all those kinds of thing. When I finished college and got my chemical engineering degree, even then I didn't think that I had much of a match for the space program. It wasn't until NASA contacted me looking for someone with my background that I made the connection. As an engineer, there's nothing more exciting and rewarding to work on than the space program. One of the most rewarding things about of my particular part is relatively so few people are working on what I work on. It is pretty neat being part of a relatively small number of people who do this kind of thing for a living.
IK: So after a designing a system that lets people drink their urine and perspiration, what's next for you?
BB: I've been transitioning out of my space station job to supporting the exploration program, in particular I'm supporting architecture studies about how we would design and operate an outpost on the lunar surface.
IK: You've sort of moved on from designing the bathroom and plumbing systems into looking at the whole house?
BB: No, I'm still the bathroom-and-kitchen guy, but the house is now on the moon.
Got something to say? E-mail your questions, comments or concerns to discoveryspace@discovery.com.
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