Wastewater recycling on the ISS

How would you feel about drinking your own urine? To most, it is a measure that would only be taken in the direst of circumstances. However, astronauts on the International Space Station (ISS) have been drinking recycled urine every day for the past decade. In 2008, the ISS installed the Water Recovery System, a wastewater recycling device which converts urine, sweat, and atmospheric moisture into drinking water. This device has allowed the ISS to be much more self-sufficient and devices like it could serve to more sustainable produce clean water on Earth.  

Water is used for a variety of tasks on the International Space Station.  Activities such as scientific experiments, food rehydration, and astronaut hygiene all require that the ISS has an ample supply of water available for its passengers. Therefore, in order to meet all of the ISS’s demands, engineers developed the Water Recovery System. In a video explaining how the Water Recovery System works, astronaut Chris Hadfield explains that the system uses “filters and a keg-sized distiller that spins to create artificial gravity as well as move the waste water along” (VideoFromSpace, 2013).

​Initially, contaminants are removed from the wastewater in a rotating distillation unit. After the distillation phase, the water enters the station’s water processor assembly where it is treated and filtered before it can be reused by the inhabitants of the ISS (NASA Johnson, 2014). Hadfield also claims that even though astronauts are drinking recycled urine, “the water that we end up with [on the ISS] is purer than most of the water that you drink [on Earth] on a daily basis” (NASA Johnson, 2014).

Thanks to the Water Recovery System, the ISS produces up to 6000 liters of water each year and has been able to successfully reclaim about 93% of its water (VideoFromSpace, 2013).  These numbers are only expected to improve as wastewater recycling technologies are further developed. In fact, new wastewater recovery systems have been developed by NASA and the University of Puerto Rico which are not only capable of converting urine into drinking water but also producing electrical energy (Nicolau, 2014). This is an important step for humankind’s ability to sustain itself for long periods of time away from the planet.

On Earth, wastewater recovery systems similar to the Water Recovery System are relevant to realizing multiple of the UN’s Sustainable Development Goals. Wastewater recovery systems are able to improve access to potable water in remote or undeveloped locations on Earth. However, these systems can also be used in more developed regions in order to diversify water resources and reduce the environmental impact that cities have on their surrounding environments. In fact, Singapore has already implemented a nationwide wastewater recovery system. Singapore’s NEWater system collects the country’s sewage water and converts it into potable water. The majority of NEWater water that is produced is used for industrial consumption and not for drinking. However, PUB, Singapore’s National Water Agency, claims that it is “well within the WHO and USEPA’s requirements for drinking water" (Pub, 2018). One day soon, clean water may not originate in lakes and rivers, but instead may come from your own toilet.

SourcesNicolau, Eduardo, José J. Fonseca, José A. Rodríguez-Martínez, Tra-My Justine Richardson,
    Michael Flynn, Kai Griebenow, and Carlos R. Cabrera. 2014. "Evaluation of a Urea
    Bioelectrochemical System for Wastewater Treatment Processes." ACS Sustainable
    Chemistry & Engineering 2, no. 4 (2014): 749-54. doi:10.1021/sc400342x
Johnson, NASA. 2014."Recycling Water on Space Station." YouTube. Uploaded March 21, 2014.
    https://www.youtube.com/watch?v=womKV58QTHY.
Pub. 2018. "NEWater." PUB, Singapore's National Water Agency. November 26, 2018.
    https://www.pub.gov.sg/watersupply/fournationaltaps/newater.
SgPUB. 2016."NEWater: A Singapore Success Story." YouTube. Uploaded August 01, 2016.
    https://www.youtube.com/watch?v=DWWU-8_4wu0&feature=youtu.be.
VideoFromSpace. 2013. "Astronauts Drink Urine and Other Waste Water | Video." YouTube. Uploaded April 29, 2013. https://www.youtube.com/watch?v=ZQ2T9OJY1lg.

---