Determination of Organic Carbon and Ionic Accountability of Various Waste and Product Waters Derived from ECLSS Water Recovery Tests and Spacelab Humidity Condensate

Development testing of the Space Station Freedom (SSF) Water Recovery and Management Subsystem is being conducted by the Marshall Space Flight Center Environmental Control and Life Support (ECLS) Branch and the Boeing Missiles and Space Division. The testing program is designed to define integrated subsystem performance, one aspect of which is assessing the quality of the waste and product waters. Recent efforts have focused on maximizing the characterization of water contaminants to more fully account for the total organic carbon and ionic conductivity of the various waste and product waters. Total organic carbon accountability improved with the application of new analytical methods for certain classes of water soluble compounds. Methods developed for the detection of aldehydes, glycols, and low-level total organic carbon are discussed. Efforts to achieve accountability for water conductivity are demonstrated through the development of a model applying basic principles of ionic equivalent conductances and equilibria relationships. Data is presented to summarize the results of accountability efforts for various ECLSS waste and product waters generated during the recent WRT Stage 4/5 Test and the humidity condensate obtained from the STS-37 Spacelab Mission and EMU testing at the Johnson Space Center.