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Pretreatment of urine using Oxone® and sulfuric acid is baselined in the International Space Station (ISS) waste water reclamation system to control odors, fix Ammonia and control microbial growth. In addition, pretreatment is recommended for long term flight use of urine collection and two phase separation to reduce or eliminate fouling of the associated hardware and plumbing with urine precipitates. This is important to the ISS application because the amount of maintenance time for cleaning and repairing hardware must be minimized. This paper describes the development of a chemical pretreatment system based on solid tablet shapes which are positioned in the inlet urine collection hose and are dissolved by the entrained urine at the proper ratio of pretreatment to urine. Building upon the prior success of the developed and tested solid Oxone tablet, a trade study and tests were completed to confirm if a similar approach would be appropriate for the sulfuric acid injection method.

Separation of a two-phase gas/liquid flow stream into the respective gas and liquid constituents with minimum or no carryover is a necessary and challenging requirement in space vehicle life support systems in a micro-gravity environment. This paper will describe testing of two types of Russian MIR water separators in a one-gravity environment at conditions typical of each separator's MIR operating envelope. Presently on MIR, two types of two-phase separator designs, a static separator design and a rotary separator design, are used in several applications. The static separator design is used in the potable water processor. In addition, static separators are used in a carbon dioxide reduction system which is under development for MIR. A rotary separator design is used in both the urine processor and the hygiene water processor systems.

Pretreatment of urine is required in space station waste water recovery systems to control odors, fix urea, and control microbial growth. Also, recent testing and experience on the shuttle orbiter waste water plumbing has discovered that pretreatment is required for long term use of urine separator hardware to reduce or eliminate fouling of the hardware and plumbing with urine precipitates. This is important for international Space Station (ISS) application because the amount of maintenance time for cleaning and repairing hardware must be minimized. This paper describes the development and initial testing of a pretreatment method produced by a trade study which looked at several different pretreatment methods. The tests used hardware previously flown as a Design Test Objective (DTO) experiment on the Orbiter.

The Shuttle Orbiter Design Test Objective (DTO) test effort of the Extended Duration Orbiter (EDO) Urinal Subassembly and the EDO Waste Collector Subsystem (WCS) has been conducted on STS–52 and STS–54 flights respectively. The objective of these DTO test flights was to prove out the new waste collection concepts and hardware including convenient and safe in–flight servicing, human factor enhancements, natural biodegradation, and hardware configuration. Actual DTO testing included real time zero gravity collection of liquid and solid human waste as well as special on–board set–ups for performance evaluation of the commode. The results of the hardware operation on these Orbiter flights along with post flight test evaluation are contained and discussed in this report. Any improvements resulting from this evaluation can be considered for use on the similar Space Station Waste Management Design.

The existing Shuttle Waste Collector Subsystem, (WCS) as designed, has a capacity limitation based on present flight durations. To accommodate the planned longer flight durations required for the Shuttle, a new concept for human waste collection, compaction and storage has been developed. This new commode is configured to fit into the existing Shuttle Waste Management compartment and also includes changes derived from the various lessons learned from the existing commode and previous crew flight debriefings. The new commode features brushless DC motor driven Fan/Separators for urine collection, individual disposable bags for fecal collection with mechanized compaction and in-flight removable canisters that allow natural biodegradation of the stored solid waste. The first full assembly of the new configuration commode has been designed, fabricated, tested and delivered to NASA/JSC Houston for further evaluation.