Dormancy Protocol of Electro Oxidation Membrane Evaporator for Urine Processing and Water Recovery

The Electro Oxidation Membrane Evaporator (EOME) is a NASA-funded advanced technology for processing wastewater electrochemically. EOME creates powerful oxidants from the salts in urine that break down organic compounds in the urine. Waste heat from the process is advantageously used to evaporate water from urine, and then the water vapor is condensed and collected for final processing before reuse. This paper describes work performed in 2022 to develop and demonstrate dormancy protocols for EOME shutdown prior to habitat dormancy and for restart upon return months later. The protocols were developed with special regard to minimizing operational crew time and consumables. The proposed protocols require adding a single 40 gram dose of acid to the wastewater on departure day, operating EOME normally for several hours, then draining the wastewater from EOME and powering off the system. Upon return to the habitat, after collection of several liters of urine in EOME, EOME is powered on and operated normally. The tests representing these protocols successfully demonstrated that EOME performance was retained after the 164-day dormancy.