Development and Fabrication of a Breadboard Electrochemical Water Recovery System

A breadboard Electrochemical Water Recovery System (EWRS) that is designed to produce potable water from a composite waste stream without the use of expendables is described in this paper. Umpqua Research Company working together with NASA/JSC developed a sequential three-step process to accomplish this task. Electrolysis removes approximately 60% of the organic contaminants from ersatz composite waste water containing a total organic carbon (TOC) concentration of 707 mg/L. The contaminants in this solution consist of organic and inorganic impurities common to laundry, shower, handwash, and urine waste water. Useful gases and organic acids are the chief by-products of the first step. The partially oxidized electrolysis solution is then transferred to the electrodialysis process where ionized organic and inorganic species are concentrated into a brine. The deionized solution of recovered water contains ∼6% of the original organic contaminants and >90% of the original water. This solution is then treated by the catalytic oxidation posttreatment process reducing the TOC level to <500 μg/L. The overall TOC reduction by EWRS is >99.9%. The technology has application for treatment of real composite waste water produced in space-based habitat environments. Sensor selection for process control, methods for foam prevention, and the characterization of individual processes leading to the optimization and integration are presented. The water recovery system's size, capacity, power usage, operation conditions, and performance in processing ersatz composite waste water are described. The breadboard system will be delivered and installed in NASA-JSC's regenerative water recovery test bed facility for evaluation and development testing.