Adu Sunday, Walker William Shane, Jackson William Andrew
Department of Civil, Environmental, and Construction Engineering, Texas Tech University, 911 Boston Avenue, Lubbock, TX 79409, USA.
Water and the Environment Research (WATER) Center, Texas Tech University, 911 Boston Avenue, Lubbock, TX 79409, USA.
Membranes (Basel). 2025 Jul 16;15(7):212. doi: 10.3390/membranes15070212.
The development of efficient and sustainable water recycling systems is essential for long-term human missions and the establishment of space habitats on the Moon, Mars, and beyond. Humidity condensate (HC) is a low-strength wastewater that is currently recycled on the International Space Station (ISS). The main contaminants in HC are primarily low-molecular-weight organics and ammonia. This has caused operational issues due to microbial growth in the Water Process Assembly (WPA) storage tank as well as failure of downstream systems. In addition, treatment of this wastewater primarily uses adsorptive and exchange media, which must be continually resupplied and represent a significant life-cycle cost. This study demonstrates the integration of a membrane-aerated biological reactor (MABR) for pretreatment and storage of HC, followed by brackish water reverse osmosis (BWRO). Two system configurations were tested: (1) periodic MABR fluid was sent to batch RO operating at 90% water recovery with the RO concentrate sent to a separate waste tank; and (2) periodic MABR fluid was sent to batch RO operating at 90% recovery with the RO concentrate returned to the MABR (accumulating salinity in the MABR). With an external recycle tank (configuration 2), the system produced 2160 L (i.e., 1080 crew-days) of near potable water (dissolved organic carbon (DOC) < 10 mg/L, total nitrogen (TN) < 12 mg/L, total dissolved solids (TDS) < 30 mg/L) with a single membrane (weight of 260 g). When the MABR was used as the RO recycle tank (configuration 1), 1100 L of permeate could be produced on a single membrane; RO permeate quality was slightly better but generally similar to the first configuration even though no brine was wasted during the run. The results suggest that this hybrid system has the potential to significantly enhance the self-sufficiency of space habitats, supporting sustainable extraterrestrial human habitation, as well as reducing current operational problems on the ISS. These systems may also apply to extreme locations such as remote/isolated terrestrial locations, especially in arid and semi-arid regions.
开发高效且可持续的水循环系统对于长期载人任务以及在月球、火星及其他星球建立太空栖息地至关重要。湿度冷凝水（HC）是一种低强度废水，目前在国际空间站（ISS）上进行回收利用。HC中的主要污染物主要是低分子量有机物和氨。这导致了水处理组件（WPA）储存罐中微生物生长以及下游系统故障等运行问题。此外，这种废水的处理主要使用吸附和交换介质，这些介质必须不断补充，且代表了相当大的生命周期成本。本研究展示了一种膜曝气生物反应器（MABR）用于HC的预处理和储存，随后进行苦咸水反渗透（BWRO）的集成系统。测试了两种系统配置：（1）定期将MABR流体送至以90%水回收率运行的间歇式反渗透，反渗透浓缩液送至单独的废液罐；（2）定期将MABR流体送至以90%回收率运行的间歇式反渗透，反渗透浓缩液返回MABR（MABR中盐分积累）。使用外部循环罐（配置2）时，该系统用单个膜生产了2160升（即1080人日）接近饮用水标准的水（溶解有机碳（DOC）<10毫克/升，总氮（TN）<12毫克/升，总溶解固体（TDS）<30毫克/升）。当MABR用作反渗透循环罐（配置1）时，单个膜可生产1100升渗透液；反渗透渗透液质量略好，但总体上与第一种配置相似，尽管运行期间没有浪费盐水。结果表明，这种混合系统有潜力显著提高太空栖息地的自给自足能力，支持可持续的外星人类居住，同时减少国际空间站目前的运行问题。这些系统也可能适用于极端地点，如偏远/孤立的陆地位置，特别是在干旱和半干旱地区。
