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The recovery of resources for reuse from the processing of diverse waste materials produced by a crew in space-based closed life support systems is essential for the success of long duration space missions. Lynntech, Inc. is investigating and developing a waste processor that uses thermal solubilization and wet oxidation at elevated pressure and an electrochemical process for solid waste processing for closed life support systems. The electrochemical process uses a packed bed anode that oxidizes waste at temperatures <100°C and operates at atmospheric pressure. This approach offers an alternative to high temperature thermal processes for solid waste treatment. Incorporated into the packed bed reactor design is a method that shows potential for regenerating a liquid electrolyte enabling the electrochemical process to operate for long periods without having to be replaced.

The post-treatment purification of water recovered from hygiene, metabolic and humidity condensate waste water is essential to regenerative water reclamation technology life support systems. Lynntech, Inc., working with NASA-JSC has developed an electrochemical reactor that generates ozone and hydrogen peroxide. The electrochemical reactor is the basis for an advanced oxidation process in which electrochemically generated oxidants are used in combination with ultraviolet irradiation to produce hydroxyl radicals in a reclaimed water stream which in turn oxidize dissolved organic impurities to carbon dioxide. This paper describes the design and fabrication of an automated breadboard reactor system based on this principle. The system operates at low temperature and requires no chemical expendables. Kinetics and performance test results are presented showing the removal of organic impurities and disinfection features to produce potable water quality.

Long duration activities by man in space requires a regenerable CO2 removal system. Current systems under study include those based on the oxygen/hydrogen fuel cell and an amine resin. Both approaches are based on well-known acid-base chemistry of CO2. Our efforts are directed at the development of electroactive CO2 carrier molecules that are capable of binding CO2 when in the reduced form and releasing CO2 in the oxidized form. The successful development of these carriers would provide the chemical basis for a more efficient CO2 removal system and offers other potential advantages as well. The general requirements and advantages of electroactive CO2 carrier molecules are discussed. In addition, studies on carrier molecules which demonstrate the feasibility of this approach are described.

The kinetics of the Sabatier methanation reaction, the reduction of carbon dioxide with hydrogen to methane and water, was investigated for 58 percent nickel on kieselguhr catalyst and 20 percent ruthenium on alumina catalyst. Differential rate data from an experimental program were correlated with a power function rate equation both for forward and reverse reactions. The kinetic parameters of activation energy, frequency rate constant and reaction order were determined for the rate equation. The values of these parameters were obtained from an Arrhenius plot of the experimental differential rate data. Also the carbon monoxide side reaction effect was measured and included in the correlation of parameters. The reaction was found to fit the rate equation experimentally within the temperature range 421°K, where the reaction effectively begins, to 800°K where the reaction rate drops and departs from the rate equation form.