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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).

The work presented in this paper summarizes the performance of subsystems used during an integrated advanced water recovery system test conducted by the Crew and Thermal Systems Division (CTSD) at NASA-Johnson Space Center (JSC). The overall objective of this test was to demonstrate the capability of an integrated advanced water recovery system to produce potable quality water for at least six months. Each subsystem was designed for operation in microgravity. The primary treatment system consisted of a biological system for organic carbon and ammonia removal. Dissolved solids were removed by reverse osmosis and air evaporation systems. Finally, ion exchange technology in combination with photolysis or photocatalysis was used for polishing of the effluent water stream. The wastewater stream consisted of urine and urine flush water, hygiene wastewater and a simulated humidity condensate.

The work presented in this paper summarizes the early results of an integrated advanced water recovery system test conducted by the Crew and Thermal Systems Division (CTSD) at NASA-Johnson Space Center (JSC). The system design and the results of the first two months of operation are presented. The overall objective of this test is to demonstrate the capability of an integrated advanced water recovery system to produce potable quality water for at least six months. Each subsystem is designed for operation in microgravity. The primary treatment system consists of a biological system for organic carbon and ammonia removal. Dissolved solids are removed by reverse osmosis and air evaporation systems. Finally, ion exchange technology in combination with photolysis or photocatalysis is used for polishing of the effluent water stream. The wastewater stream consists of urine and urine flush water, hygiene wastewater and a simulated humidity condensate.

This paper addresses the derivation of chemical ersatz recipes for use in the evaluation of development hardware designed for advanced spacecraft water recovery systems. The recipes simulate characteristics of wastewater generated on a transit mission and on an early planetary base (EPB). In addition, recipes are provided which simulate the water quality of the early planetary base wastewater as it moves through a combination biological and physical-chemical water recovery system. These ersatz are considered to be accurate representations of the wastewater as it passes through primary, secondary, and tertiary processing stages. The EPB ersatz formulas are based on chemical analyses of an integrated water recovery system performance test that was conducted over a period of one year. The major inorganic and organic chemical impurities in the raw wastewater, and in the effluent from the various subsystems, were identified and quantified.

The Biological Wastewater Processor Experiment Definition team is performing the preparatory ground research required to define and design a mature space flight experiment. One of the major outcomes from this work will be a unit-gravity prototype design of the infrastructure required to support scientific investigations related to microgravity wastewater bioprocessing. It is envisioned that this infrastructure will accommodate the testing of multiple bioprocessor design concepts in parallel as supplied by NASA, small business innovative research (SBIR), academia, and industry. In addition, a systematic design process to identify how and what to include in the space flight experiment was used.

Ground-based laboratory and closed-chamber human tests have demonstrated the ability of microbial-based biological processors to effectively remove carbon and nitrogen species from regenerable life support wastewater streams. Application of this technology to crewed spacecraft requires the development of gravity-independent bioprocessors due to a lack of buoyancy-driven convection and sedimentation in microgravity. This paper reports on the development and testing of membranebased biological reactors and addresses the processing of planetary and International Space Station (ISS) waste streams. The membranes provide phase separation between the wastewater and metabolically required oxygen, accommodate diffusion-driven oxygen transport, and provide surface area for microbial biofilm attachment. Testing of prototype membrane bioprocessors has been completed.