Status of the Regenerative ECLSS Water Recovery System

Abstract

NASA has completed the delivery of the regenerative Water Recovery System (WRS) for 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 final effort to deliver the hardware to the Kennedy Space Center for launch on STS-126, the onorbit status as of April 2009, and describes some of the technical challenges encountered and lessons learned over the past year.

Strategies for stabilizing nitrogenous compounds in ECLSS wastewater: Top-down system design and unit operation selection with focus on bio-regenerative processes for short and long term scenarios.

“…Consumable use is low, with no pH control or other chemical additions (besides oxygen gas delivered to the hollow fibers). Unlike pretreatment or physical-chemical urea hydrolysis, the HFMB can handle VOC's and, when a combined wastewater stream is used, TOC removal can be over 95%, which can significantly reduce the work of downstream polishing 5 . The effluent is high in ammonia and dissolved carbon dioxide which allows nutrient recovery, refrigeration recovery, or atmospheric gas producing activities.…”

“…Water recovery is dependent on a number of factors, with one of the main limitations being salting out of the brine and hardness fouling the unit. The treated urine along with hygiene water and humidity condensate are then passed through a series of air-liquid separators to remove entrained air, multifunction filters to remove suspended and dissolved solids, a catalytic oxidation reactor to remove small chain organic compounds, and ion exchange to remove the rest of the dissolved ions and add iodine to the now potable water 5 . A simple schematic of the current ISS system is shown in Fig.…”

Life Support for a Low-Cost Lunar Settlement: No Showstoppers

“…The WPA produces iodinated water that is tested by onboard sensors and delivered through a potable water bus to the oxygen generation system (OGS) for oxygen production, the potable water system for crew consumption, and other systems/payloads. 9 Air recycling. Air recycling is accomplished on the ISS using (i) an OGS, (ii) a carbon dioxide removal assembly (CDRA), (iii) a Sabatier reactor, (iv) air contamination control (ACC), and (v) temperature and humidity control (THC) (Figs.…”