NASA to test wastewater treatment system for long-duration space missions

NASA’s Kennedy Space Center in Florida sent a mobile wastewater treatment system to the University of North Dakota in Grand Forks. The unit will help prepare for long-duration missions on the Moon and Mars.

Graduate students at the university will integrate the Divergent Deployable Wastewater Treatment Facility with the university’s Integrated Lunar/Martian Analog Habitat to test the combined units under conditions designed to closely mimic the challenges of operating on another planetary surface.

Housed inside an 8.5-by-24-foot trailer, the facility brings together three biological reactor systems, a vertical garden, water-polishing hardware, environmental monitoring, autonomous control software, and safety systems. The trailer was outfitted at NASA Kennedy to function as a deployable laboratory and to travel between at least two simulation test sites as the technology matures.

Unlike wastewater systems on Earth, this facility keeps waste streams separate. That divergent approach is important for small crews, because wastewater from four to eight people can be highly concentrated. Urine, hygiene water, laundry water, fecal waste, and food waste each contain different levels of salts, solids, carbon, nitrogen, phosphorus, and other compounds. Treating them separately allows each stream to be processed by the reactor best suited for the job.

To do that, the system uses three different bioreactors to treat waste streams. The Anaerobic Phototrophic Membrane Bioreactor processes fecal and food waste and converts it into a nutrient-rich wastewater that can support plant growth. The Suspended Aerobic Membrane Bioreactor processes urine and flush water. The Membrane Aerated Biological Reactor treats graywater from hygiene and laundry activities.

Collectively, the bioreactors process nutrients to feed the facility’s vertical garden and prepare the water for reuse. Inside that garden, crops will grow hydroponically, or without using soil, by using nutrient solutions derived from the bioreactors. Researchers will compare crop performance with plants grown using standard hydroponic nutrients.

At North Dakota, under a NASA EPSCoR (Established Program to Stimulate Competitive Research) grant, the facility was connected to the Integrated Habitat through a bathroom interface that includes a urine-diverting toilet. The setup will allow different waste streams to be separated at the source and sent to the correct treatment systems.

In parallel, the team is developing novel membrane-based separation technologies intended for future integration into the divergent wastewater facility to improve water recovery efficiency, contaminant rejection, and overall system resilience for long-duration habitation missions.

NASA researchers also are exploring how wastewater-recovered resources could support in-space manufacturing. One effort is studying how nutrient-rich water from bioregenerative wastewater systems could feed microbes that produce lactic acid, which can be turned into polylactic acid. The material could one day serve as a binder for 3D printing with lunar or Martian regolith, the loose, fragmental surface material, or could be used for replacement parts, extending the value of recovered waste beyond water and food systems.