The Brine Evaporation Bag (BEB) was designed for dewatering the residual brine generated from a spacecraft's primary wastewater treatment systems. The BEB is a closed bag structure with hydrophobic membranes in its sidewalls to facilitate the dewatering of the concentrated brine that fills it. In order to provide the energy required to dewater the brine, the BEB is placed inside a heating chamber such as the Heat Melt Compactor (HMC). As the temperature of the brine increases, the water in the brine transforms to water vapor. The water vapor then leaves the brine and passes through the membrane installed in the sidewall of the BEB. The HMC provides the condensation and subsequent handling of the water produced by this process and delivers it to the primary water processor. As a result, the BEB is left with either a highly concentrated brine liquid or a solid inside the bag. The BEB process has an advantage over traditional drying techniques in that it is resistant to precipitation and scaling failure. The focus of this paper is on the initial design concepts and testing of the BEB. This includes the testing of various membrane materials: an expanded polytetrafloroethylene, two expanded polypropylene, and a reticulated polypropylene. The results of this study showed that the reticulated polypropylene was the most mechanically stable when compared to the other membrane materials. The BEB was also able to achieve 96% water recovery without fouling the membrane.
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