Lightweight Contingency Urine Recovery System Concept Development 2007-01-3037
The Lightweight Contingency (LWC) Urine System is a contingency urine recovery system that produces a liquid food product. It does this on an individual (personal) basis thus removing the concerns associated with shared urine recycle. The system uses activated carbon treatment followed by forward osmosis (FO) to provide a hydration and electrolyte fluid (a sports drink) for crew consumption.
The system hardware consists of an initial urine collection device containing an activated carbon matrix. This is followed by transfer of the treated urine into an FO membrane treatment cell. The FO treatment cell consists of a 2 L plastic bag. This FO bag is a robustly constructed intravenous (IV) surgical fluid drip bag equipped with input and output ports and an internally mounted cellulose triacetate membrane. All components are light weight disposable plastic, the system is potentially wearable, and it uses no electrical power.
Current performance testing indicates acceptable flux rates and water recovery percentages over 6 to 12 hours of optimal urine treatment. Using the unmodified off the shelf activated carbon and FO treatment membrane, inorganic contaminant removal is better than 90% and Total Organic Carbon (TOC) removal is better than 99% of initial urine values. Final TOCs are in the 25 mg/l to 100 mg/l range for the current, commercially available FO cell and actual urine. Urea/NH4, and flux testing to date has used the commercial membrane and controlled ersatz urine.
Initially, the system's urine recycle function is intended for contingency/emergency use only, but will do so at a significant mass savings when compared to contingency water supplies and/or conventional water treatments.