LSU Mechanical Engineering Assistant Professor Manas Gartia is leading research into water purification and recycling systems in NASA spacecrafts. The research aims to make use of the radiation in space to curb a natural, yet tenacious, problem in all water filtration: membrane fouling.
Fouling is the process of membrane degradation due to particles depositing throughout the membrane. The radiation will specifically be used to eliminate biofouling, which refers to when microbial growth accumulates on the membrane as a biofilm and reduces water quality.
Based on a synthesized membrane material a student was working with for unrelated purposes, Gartia pitched his idea for a radiation-activated oxygen species with water filtration applications to NASA scientists. Gartia's idea piqued the interest of NASA Advisor Michael Flynn, a principal investigator into water recycling technology.
“Flynn was very excited," Gartia said. "He said ‘I’ve never seen this kind of idea before.’”
The membrane must be of a particular material that allows ionizing radiation to penetrate deeply into it and reduce bacterial growth. Only the high-frequency, short-wavelength radiation in space will suffice.
“Other radiation like UV Light will not penetrate deeply enough into the membrane," Gartia said. "You need to use the gamma and X-rays already available in space."
According to Gartia, Flynn wanted the technology to be used for NASA’s Gateway project, which aims to place a space station in orbit of the moon. Unlike the ISS which sees frequent visits and restocking, Gateway may go months without water resupplying, increasing the importance of an economical and minimalist approach to collecting resources.
“Even in space bacteria can grow," Gartia said. "This system is passively activated by radiation, so we won’t need to bring any extra power source to deal with it.”
As for safety, avoiding radiation contamination is a natural worthy. Gartia assures the filtration system will utilize materials with sufficiently high atomic masses in shielding enclosures to avoid any danger.
He’s also interested in applying this technology to filtration systems here on Earth.
Gartia said oil and gas industries extract about 2.1 billion gallons of produced water per day. Currently, most of this extracted water is injected back into the earth as a means of disposal, giving it no utility.
“If we can purify this water by separating these contaminants using some membrane technology, we can further utilize all that water," Gartia said.
Employing high-pressure and temperature thermal reactors, Gartia’s lab now focuses on bringing the design to something fully operational in the real world.
“We need to ensure this is stable," Gartia said. "We have looked into the science theory behind it, and now we turn to the engineering necessary to make it work in real situations. At the industrial scale we will also have to eventually scale it up.”
Gartia anticipates a system that can demonstrate the technology will be completed in the next two to three years.