Evaluation of Alternative Urine Pre-Treatment Strategies

摘要

The goal of urine pre-treatment for space missions is to prevent ammonia formation, other off-gas formation, microbial growth and uric acid precipitation. Additionally, urine pre-treatment can reduce biological activity to prevent bio-fouling of systems. While current treatment methods are adequate to prevent volatilization and most scaling and growth issues, they are generally not compatible or adversely affect potential water processing applications. Significant advantages may be obtainable by developing new pre-treatment strategies designed to both stabilize urine for storage but also optimize its stabilization to promote ease of treatment in potential physio/chemical processes. The specific aim of the work was to explore alternative urine pre-treatment alternatives to oxone that may be used synergistically with proposed technologies for urine recycling while still meeting stabilization requirements. Advanced oxidation technologies, such as ozone and UV may be used to pre-treat urine. Both technologies can be operated on demand and have a significant advantage over consumable technologies and they have the potential to meet the minimum requirements of urine stabilization including inactivation of urease enzyme, disinfection, and oxidation of noxious odors. The other urine pre-treatment strategy considered was struvite (MgNH_4PO_4 ·6H_2O) formation. Struvite reactions have the ability to remove ammonia which reduces the potential for ammonia off-gas formation.