Macro- and Micro-scale Contaminant Removal and Resource Recovery from Urine via the Freeze Concentration Process

摘要

Resource recovery, including that of urine water extraction, is one of the most crucial aspects of long-term life support in interplanetary space travel. This effort consequently examined an innovative approach to processing raw, undiluted urine based on low-temperature freezing. A strategy uniquely different from NASA's current emphasis on either 'integrated' (co-treatment of mixed urine, grey, and condensate waters) or 'high-temperature' distillation processing strategies, whereby this liquid freeze-thaw (LiFT) procedure avoids both chemical and microbial cross-contamination concerns while at the same time securing highly desirable reductions in likely energy requirement levels. In essence, this research effort investigated an innovative, first-generation eutectic freeze concentration strategy for extraction of potable water from urine. The existing project's experimental unit, which couples the sequential steps normally associated with conventional eutectic freeze crystallization (e.g., seed crystal growth followed by ice ripening, concentration, washing, extraction, and final ice-water recovery), has proven capable of generating high-quality product water, (i.e., greater than 99% reduction of contaminant concentrations; inorganics, organics, biological and antibiotics), along with a theoretical percent water recovery of 85-95%.