An Analysis of Urine Pretreatment Methods for Use on Space Station Freedom

Water reclamation from human urine will be the basis of the closed loop Water Recovery Management (WRM) system on Space Station Freedom (SSF). Pretreatment is necessary to collect and process urine, fix and prevent ammonia formation, inhibit microbial growth and prevent solids precipitation. Pretreatment must be accomplished immediately upon collection to prevent damage to urine collection and handling equipment. Currently, a chemical injection scheme is an integral part of the SSF Urinal design. The reagents used will be based on compatibility with Urinal and Urine Processor components, performance of necessary pretreatment functions, quality of reclaimed water, resupply costs and development risks. These factors are compared for various pretreatment methods currently under consideration for use on SSF.