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Although bioprocessors have been successfully tested in ground test experiments as primary wastewater processors [1, 2 and 3], the transition required for operation of a bioprocessor in microgravity is complicated by the absence of gravity and buoyancy-driven convection. Gases are present in the wastewater bioprocessor from numerous sources including aeration, metabolic production and operation. This paper presents an innovative approach to the delivery of metabolically-required oxygen to a bioprocessor. A bioprocessor that provides oxygen delivery and bacterial support using membranes has been developed and tested during the past two years. Bench-top laboratory results have demonstrated that Total Organic Carbon (TOC) degradation above 95%, and nitrification above 80% can be maintained, while denitrification typically ranged between 5-25% in a membrane bioprocessor system (MBS).

A gas trap is being developed for use in the internal thermal control system (ITCS) of Space Station Freedom. The function of the gas trap is to remove and vent noncondensed gases (NCG) that may be entrained in the ITCS water loop. Noncondensed gas bubbles in excessive concentrations can cause the performance of the centrifugal pump to degrade, block coolant flow in remote components, and cause inaccuracies in instrumentation readings. A design has been created utilizing polypropylene hydrophobic and nylon hydrophilic membranes. The hydrophobic membrane allows gas transfer from the water/gas mixture across the membrane to ambient, and blocks liquid flow at the expected ITCS pressure levels. The hydrophilic membrane permits ITCS water to flow through the membrane, and blocks noncondensed gas at the expected water pressure differential. The water leaving the hydrophilic membrane is degassed and exits from the gas trap.