Sodium Chloride Removal from International Space Station Wastewater Brine to Generate Plant Fertilizer



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50th International Conference on Environmental Systems


Water is a critical resource for human exploration beyond low earth orbit. There are two general mechanisms for wastewater recovery. The current practice on the International Space Station (ISS) is vapor compression distillation, which requires a significant amount of consumables and has a water recovery rate of around 75%. An alternative approach is a biological water processor (BWP), integrated with a forward osmosis secondary treatment system (FOST). The integrated system is expected to recover 95% of the initial wastewater volume. The remaining 5% is lost as a concentrated brine. For a closed-loop water recovery system, all nutrients should be recovered and reused. For far-term life support, plant systems will be introduced to grow in situ foods, as well as to regenerate O2 and remove CO2 from cabin air. To do so will require a continuous flow of nutrients or fertilizer. The wastewater brine provides a rich source of nutrients for plants, but its high sodium content presents a challenge for most food crops. Direct recycling of urine to crops for life support was tested in Bios-3 (Russia) and resulted in salinization of growth systems. Halophytic plants have been tested with high Na inputs but their yields are low. A thermal swing process has been proposed to separate NaCl from other salts in wastewater for use as plant fertilizer. The paper reports the initial proof of concept testing results, which showed that the thermal swing process is a promising approach for NaCl reduction from wastewater, as well as the tasks planned for further development.


Tesia Irwin, The Bionetics Corporation
Angie Diaz, URS Federal Services Inc
Wenyan Li, URS Federal Services
Griffin M. Lunn, QinetiQ North America
Lawrence Koss, Enterprise Advisory Services,
Raymond Wheeler, NASA
Michael Callahan, NASA
Andrew Jackson, Texas Tech University
Luz M. Calle, NASA
ICES303: Physio-Chemical Life Support- Water Recovery & Management Systems- Technology and Process Development
The 50th International Conference on Environmental Systems was held virtually on 12 July 2021 through 14 July 2021.


wastewater, sodium removal, fertilizer, brine, BWP