As part of the NASA Specialized Center of Research and Training in Advanced Life Support (NSCORT-ALS) at Purdue University, a complementary disinfection process, which uses ultra-violet (UV) radiation as the primary disinfectant and iodine as the residual disinfectant, is being developed. UV radiation was selected as the primary disinfectant because it is effective at inactivating a broad spectrum of microorganisms and has minimal potential to form disinfection byproducts. Iodine, which is effective at inactivating many microorganisms was selected as the residual disinfectant because it has the potential for dual use as an on-line UV monitor and a disinfectant. The dual use of iodine will be achieved using different iodine species. I2 will be used for secondary disinfection. Iodide (I-) and iodate (IO3-) will be used in the chemical actinometer to monitor the efficacy of the UV system. The actinometer system will consist of a small capillary tube installed within the UV reactor through which an I-/IO3- solution is pumped. When the actinometer solution is exposed to UV radiation, triiodide (I3-) is produced. The quantum yield for I3- formation will be used to evaluate the performance of the UV system. The iodine species present in the photo-reacted solution must be converted to I2 for use as a secondary disinfectant. Because of toxicological issues related to iodine exposure, residual iodine will be removed from the potable water at the point-of-use. The removed iodine will be transformed back to I- and reused in the actinometer system. The iodine recycle process will be continued throughout the mission duration, thereby limiting the need for
Related Documents:WM1, WM2, WM3, WM8
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Ernest R. Blatchley III
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Project 8 - Water Disinfection
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Internal Documents: Management: External Advisory
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