The Electro Oxidation Membrane Evaporator (EOME) is a NASA-funded advanced technology that combines advanced oxidation process (AOP) and membrane distillation (MD) for water recovery from wastewater. The redox cell in EOME creates powerful oxidants that break down organic compounds in the urine. Waste heat from AOP is advantageously used to evaporate water from urine. Water vapor is condensed and filtered for final processing before reuse. This paper describes work performed in 2023 to continuously run EOME and recover water from urine. Urine doses were added intermittently to the system while urine/wastewater that had been already in the system was being processed continuously. The redox current was 25 – 50 A. The average water evaporation rate was 12.5 g/min. In the first half of the test, the wastewater volume in the loop was decreased to 3 – 3.6 L after each dose by evaporating water. After achieving 97% water recovery, the max wastewater concentration and conductivity after each dose were maintained at ~95% and ~230 mS/cm, respectively. A total of 132-L urine was processed and 97.7% water recovery was achieved. Wastewater pH remained around 7, and conductivity was found to be a promising direct indicator of the progress in the electrochemical wastewater processing.
Arai et al. (Sun,) studied this question.