POTENTIALLY TOXIC MICROORGANISMS CAN GROW IN ACTIVATED CARBON AND ION EXCHANGE BEDS USED FOR POST-TREATMENT IN SPACECRAFT WATER RECOVERY SYSTEMS.

POTENTIALLY TOXIC MICROORGANISMS CAN GROW IN ACTIVATED CARBON AND ION EXCHANGE BEDS USED FOR POST-TREATMENT IN SPACECRAFT WATER RECOVERY SYSTEMS. ORDINARY BIOCIDES DISSOLVE IN WATER AND, IF USED, WOULD LEACH FROM THE BEDS. THIS PROJECT INVOLVES BOUND BIOCIDES THAT WOULD NOT LEACH INTO WATER OR AFFECT THE PURIFICATION PROPERTIES OF POST-TREATMENT SYSTEMS. TWO APPROACHES WILL BE TAKEN USING BIOCIDAL AGENTS THAT ARE MADE NON-LEACHABLE BY CHEMICAL OR FREE RADICAL ATTACHMENT TO THE POST-TREATMENT BED: (1) QUATERNARY AMMONIUM MONOMER BIOCIDES ATTACHED TO CARBON OR ION EXCHANGE RESIN SURFACE VIA CHEMICAL REACTION OR BY FREE RADICAL GRAFTING USING CERIUM, OZONE, PEROXIDE, OR UV ACTIVATION AND (2) IN SITU BONDING OF ZINC PEROXIDE WITH CARBON BLACK AND/OR ION EXCHANGE RESIN FORMED BY REACTION OF ZINC ACETATE WITH HYDROGEN PEROXIDE IN SITU. FOR BED TREATMENTS, TEST METHODS FOR OBSERVING GROWTH OF BACTERIA ON AN ANION EXCHANGE OR ACTIVATED CARBON BED WILL INCLUDE EITHER ASTM G21(22) AND/OR THE DEVELOPMENT OF A MORE RAPID TEST METHOD USING CIRCULATING RIVER WATER. MODIFIED ACTIVATED CARBON AND ION EXCHANGE BEDS WILL BE EXAMINED FOR POSSIBLE LOSS OF PURIFICATION PROPERTIES, AND THE EFFLUENT WILL BE ANALYZED BY MASS SPECTROMETRY FOR PRESENCE OF TOXIC PRODUCTS.