Status of the Regenerative ECLS Water Recovery System

Abstract

The regenerative Water Recovery System (WRS) has completed its first full year of operation on the International Space Station (ISS). The major assemblies included in this system are the Water Processor Assembly (WPA) and Urine Processor Assembly (UPA). This paper summarizes the on-orbit status as of May 2010, and describes the technical challenges encountered and lessons learned over the past year.

Impact of acids on the structure and composition of Linde Type A zeolites for use in reverse osmosis membranes for recovery of urine-containing wastewaters

“…Two of the acid-producing compounds, sulfuric acid and chromium(VI) oxide, are added to the raw wastewater to inhibit microbial growth and prevent reaction of urea to produce ammonia [3]. The other two acid-producing compounds, sodium dihydrogen phosphate and potassium dihydrogen phosphate, occur naturally in human urine [3].…”

“…To aid in the reduction of dependence upon land-based resources [2], the National Aeronautics and Space Administration (NASA) is actively seeking methods for sustainable water recovery. Urine-containing wastewater is a proven excellent recyclable water source in space applications [3]; these waters are the focus of the Urine Processing Assembly (UPA) on the International Space Station (ISS). However, the current water recovery system (of which the UPA is a component) on the ISS recycles only 70% of the wastewater produced onboard, leaving 30% as a corrosive brine solution that is stored for later disposal as hazardous waste [3].…”

“…Urine-containing wastewater is a proven excellent recyclable water source in space applications [3]; these waters are the focus of the Urine Processing Assembly (UPA) on the International Space Station (ISS). However, the current water recovery system (of which the UPA is a component) on the ISS recycles only 70% of the wastewater produced onboard, leaving 30% as a corrosive brine solution that is stored for later disposal as hazardous waste [3]. Further processing of this brine through osmotic processes is a desirable option for increasing water recovery aboard the ISS.…”

Supportability Challenges, Metrics, and Key Decisions for Future Human Spaceflight

“…For example, the ISS ECLSS system has experienced several instances of component failure and/or degraded performance due to unanticipated issues, 18,44 63 or even changes in the concentration of calcium in crew urine due to physiological changes resulting from the microgravity environment. 63,64 Distributions on the values of failure rates or other parameters can be used to account for some of this uncertainty, but unknown risks will always remain.…”

Next Generation Life Support Project: Development of Advanced Technologies for Human Exploration Missions

“…The AWP is being designed to recycle more than 95% of exploration wastewater, increasing closure compared to the state of the art. The AWP could ultimately replace the funcsions of the Urine Processor Assembly (UPA) and reduce or eliminate the need for the multifiltration beds of the Water Processor Assembly (WPA) of the International Space Station (ISS) 13 .…”