Browsing by Author "Arai, Tatsuya"
Now showing 1 - 6 of 6
- Results Per Page
- Sort Options
Item 97% Water Recovery from Urine using Electro Oxidation Membrane Evaporator(2024 International Conference on Environmnetal Systems, 2024-07-21) Arai, Tatsuya; Fricker, JohnThe 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.Item Continued Development of the Electro Oxidation and Membrane Evaporator for Urine Processing and Water Recovery(50th International Conference on Environmental Systems, 7/12/2021) Arai, Tatsuya; Fricker, JohnThis paper describes the continued development of wastewater processing and water reclamation applications using the Electro Oxidation Membrane Evaporator (EOME). The EOME purifies wastewater (augmented urine, flush water, and pretreat) by breaking down organic compounds with powerful oxidants such as reactive oxygen species (ROS) and chlorine containing species (CCS) created from oxygen, water, and chloride salts in the wastewater on Boron?Doped?Diamond (BDD) coated electrodes. Waste heat generated from the electro?oxidation process is used to facilitate water evaporation through a gas?liquid contactor (GLC), allowing water evaporated from the wastewater to be recovered elsewhere. The purpose of developing and testing the EOME is to explore its potential for reducing the size, mass, power, and complexity of an Exploration wastewater treatment system, to increase the recovery of useful gases from waste products, and reduce waste volume. A full scale bench top EOME was developed based on previous work, including upgraded GLCs for evaporating water and a trace contaminant control system (TCCS) to capture previously identified off-gassed contaminants in the humid air. Tests with human urine were performed and gas and wastewater were sampled to help understand the EOME performance.Item Development status of air revitalization system in JAXA closed ECLSS for future crew module(48th International Conference on Environmental Systems, 2018-07-08) Sakai, Yoko; Arai, Tatsuya; Suehiro, Tomoya; Ito, Tsuyoshi; Oka, Toshiharu; Waseda, Shinpei; Shima, Asuka; Sakurai, MasatoThe Japan Aerospace Exploration Agency (JAXA) has been developing closed Environmental Control and Life Support System (ECLSS). Air revitalization system in closed ECLSS consists of five subsystems, CO2 removal assembly, Trace contaminant control assembly, CO2 reduction assembly, O2 generation assembly, and methane decomposing assembly. In this paper, development status of each subsystem exclude trace contaminant control assembly is reported. In CO2 removal system development, CO2 for almost 4 crews collected by low and narrow range of temperature swing of newly developed adsorbent. Full-scale test model of CO2 reduction system, loaded low temperature catalyst JAXA developed, has been completed. Prolonged test of electrolysis cell is in progress for examination O2 generation system architecture. Fundamental data for scale-up test of methane decomposition was conducted.Item Dormancy Protocol of Electro Oxidation Membrane Evaporator for Urine Processing and Water Recovery(2023 International Conference on Environmental Systems, 2023-07-16) Arai, Tatsuya; Fricker, JohnThe 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.Item Swing Bed Scrubber Design and Test Integration Results for Carbon Dioxide Removal in the Ventilation Test Loop 2.0(48th International Conference on Environmental Systems, 2018-07-08) Chullen, Cinda; Conger, Bruce; Mcmillin, Summer; Swickrath, Mike; Kanne, Bryan; Fricker, John; Arai, TatsuyaNASA is developing an advanced portable life support system (PLSS) to meet the needs of a new NASA advanced space suit. The PLSS provides the necessary oxygen, ventilation, and thermal protection for an astronaut performing a spacewalk. The PLSS ventilation subsystem is responsible for providing adequate carbon dioxide (CO2) and water vapor removal. To experimentally validate the performance of CO2 removal and advanced CO2 sensing systems, NASA Johnson Space Center developed the Ventilation Test Loop 2.0 (VTL2) and tested the Oceaneering Swing Bed Scrubber (SBS) that was fabricated and delivered under the Constellation program in 2015. The SBS was designed to continuously remove CO2 and water vapor from a space suit ventilation loop with a pair of thermally integrated amine beds that alternately adsorb and desorb water vapor and CO2. The SBS hardware was recently resurrected and reassembled to support a full battery of performance testing in the VTL2. This paper describes the design and development of the SBS and the VTL2 along with the performance test results of the SBS.Item Urine Processing and Water Recovery using Electro Oxidation and Membrane Evaporator(2020 International Conference on Environmental Systems, 2020-07-31) Arai, Tatsuya; Fricker, JohnThe Electro Oxidation and Membrane Evaporator (EOME) is a partial gravity compatible urine processor to oxidize urine and recover water from urine. The EOME purifies wastewater (augmented urine, flush water, and optional pretreat) by breaking down organic compounds with powerful oxidants such as reactive oxygen species and chlorine containing species. Waste heat generated from the electro-oxidation process facilitates water evaporation through a gas-liquid contactor (GLC), allowing water evaporated from the wastewater to be recovered elsewhere. The resulting brine is offloaded to a brine water recovery system to recover the remaining water. A full scale EOME was designed and 10 L of raw human urine was processed for oxidation. EOME successfully converted the urine into clear acid, dissolved precipitation, and removed total organic carbon (TOC). In order to test worst case for water evaporation, concentrated urine that simulated concentration after ~80% water evaporation was also tested. EOME demonstrated further water evaporation. The results indicate EOME has potential benefits including producing self-generated pretreat and flush water, self-cleaning the wastewater loop, delaying precipitation during water evaporation by oxidizing dissolved solids, and recovering useful gases (e.g., CO2, H2O, N2) from the oxidized components of wastewater which further closes the ECLSS loop. Future work includes increasing water evaporation rate, analysis of gas species leaving the GLC, development of a gas scrubber, and flight concept development.