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The Vapor Phase Catalytic Ammonia Removal (VPCAR) technology has been previously discussed as a viable option for the Exploration Water Recovery System. This technology integrates a phase change process with catalytic oxidation in the vapor phase to produce potable water from exploration mission wastewaters. A developmental prototype VPCAR was designed, built and tested under funding provided by a National Research Announcement (NRA) project. The core technology, a Wiped Film Rotating Device (WFRD) was provided by Water Reuse Technologies under the NRA, whereas Hamilton Sundstrand Space Systems International performed the hardware integration and acceptance test of the system. Personnel at the Ames Research Center performed initial systems test of the VPCAR using ersatz solutions. To assess the viability of this hardware for Exploration Life Support (ELS) applications, the hardware has been modified and tested at the MSFC ECLS Test Facility.

The Water Processor Assembly (WPA) for use on the International Space Station (ISS) includes various technologies for the treatment of waste water. These technologies include filtration, ion exchange, adsorption, catalytic oxidation, and iodination. The WPA hardware implementing portions of these technologies, including the Particulate Filter, Multifiltration Bed, Ion Exchange Bed, and Microbial Check Valve, was recently qualified for chemical performance at the Marshall Space Flight Center. Waste water representing the quality of that produced on the ISS was generated by test subjects and processed by the WPA. Water quality analysis and instrumentation data was acquired throughout the test to monitor hardware performance. This paper documents operation of the test and the assessment of the hardware performance.

Novel mesoporous bimetallic oxidation catalysts are described, which are currently under development for the deep oxidation (mineralization) of aqueous organic contaminants in wastewater produced on-board manned spacecraft, and lunar and planetary habitats. The goal of the ongoing development program is to produce catalysts capable of organic contaminant mineralization near ambient temperature. Such a development will significantly reduce Equivalent System Mass (ESM) for the ISS Water Processor Assembly (WPA), which must operate at 135°C to convert organic carbon to CO2 and carboxylic acids. Improvements in catalyst performance were achieved due to the unique structural characteristics of mesoporous materials, which include a three-dimensional network of partially ordered interconnected mesopores (5-25 nm).

The Conductivity Sensor designed for use in the Node 3 Water Processor Assembly (WPA) was based on the existing Space Shuttle application for the fuel cell water system. However, engineering analysis has determined that this sensor design is potentially sensitive to two- phase fluid flow (gas/liquid) in microgravity. The source for this sensitivity is the fact that free gas will become lodged between the sensor probe and the wall of the housing without the aid of buoyancy in 1-g. Once gas becomes lodged in the housing, the measured conductivity will be offset based on the volume of occluded gas. A development conductivity sensor was flown on the NASA Microgravity Plane (KC-135) to measure the offset, which was determined to range between 0 and 50%. This range approximates the offset experienced in 1-g gas sensitivity testing.

Hamilton Sundstrand Space Systems International (HSSSI) is currently under contract with NASA MSFC to design, fabricate and deliver the Water Processor Assembly (WPA) for the International Space Station (ISS). As part of this effort HSSSI has developed an oxidation catalyst for the catalytic reactor assembly in the WPA. This paper discusses full-scale development reactor testing and the status of the life testing of the oxidation catalyst used in the reactor.

An evaluation of a development Condensing Heat Exchanger (CHX) was conducted at the MSFC ECLS Test Facility. The purpose of this test was to assess the effect of particulates and metals in the CHX condensate on downstream components, primarily the Air/Water Separator and the Back Pressure Relief Valve (BPRV). This test was performed using a flight-like CHX to simulate the particulate load and the concentration of metals from the ISS CHX coating. Two designs of the flight BPRV used on ISS were tested to assess the effect of particulates on the valve operation. As expected, the original design of the BPRV showed it was susceptible to particulate blockage. Particulate levels were not as significant as those observed in condensate generated during ground tests of the Lab and Airlock modules.

Removal of low-molecular weight, polar, non-ionic contaminants such as urea and alcohols from aqueous solution is being accomplished using immobilized enzyme technology. Immobilized urease is used to catalyze urea hydrolysis for subsequent removal as ammonia. An alcohol oxidase enzyme-based catalyst is used to catalyze oxidation of alcohols, aldehydes, and similar compounds to organic acids, which are removed by ion exchange. Fixed bed reactors were successfully developed and delivered to NASA-MSFC for a segment of the Phase III Core Module Integrated Facility (CMIF) Water Recovery Test. Wastewater generated in the End-use Equipment Facility (EEF) was purified using a combination of Multifiltration Unibeds and Enzyme Unibeds. The enzyme beds effectively removed the targeted organics to levels below detection limits (<100-400 ppb). Also, based on the amount of TOC removed, the enzyme beds removed unidentified organic contaminants beyond those specifically targeted.