Air Revitalization for Vacuum Environments

NASA's Liquid Sorbent Carbon Dioxide Removal System was designed as an alternative to the current CO2 removal technology used on the International Space Station (ISS), which uses solid zeolite media that is prone to dusting, has a low absorption capacity, and requires high regeneration temperatures and frequent maintenance. Motivated by CO2 removal systems on submarines, NASA innovators began investigating the use of liquid sorbents. Liquid sorbents have a capacity four times greater than solid zeolites, require low regeneration temperature, and need fewer unreliable moving mechanical parts than solid based systems. While submarine CO2 scrubbers spray an adsorbing chemical directly into the air stream and allow the liquid to settle, NASA's new system uses a capillary driven 3D printed microchannel direct air/liquid contactor in a closed loop system. The Liquid Sorbent Carbon Dioxide Removal System is robust and reliable, while being low in weight, volume, and power requirements. The system is capable of reaching equilibrium when the liquid sorbent surface is being regenerated at a rate equal to the rate of absorption into the liquid.

This invention is a system and associated method that is a two step process. It provides a contaminant treatment pouch, referred to as a urine cell or contaminant cell that converts urine or another liquid containing contaminants into a fortified drink, engineered to meet human hydration, electrolyte and caloric requirements. It uses a variant of forward osmosis (FO) to draw water from a urine container into the concentrated fortified drink as part of a recycling stage. An activated carbon pretreatment removes most organic molecules. Salinity of the initial liquid mix (urine plus other) is synergistically used to enhance the precipitation of organic molecules so that activated carbon can remove most of the organics. A functional osmotic bag is then used to remove inorganic contaminants. If a contaminant is processed for which the saline content is different than optimal for precipitating organic molecules, the saline content of the liquid should be adjusted toward the optimal value for that contaminant.

Because resupply of commodities for long duration space missions would be prohibitively expensive and could take an extensive length of time to reach habitats in orbit around or on other planetary bodies, it is critical that astronauts have the ability to recycle and reuse local waste streams to provide resources such as clean water, fuel, and nutrients for growing plants. Scientists at Kennedy Space Center and the University of South Florida have developed a technology that addresses this critical mission need. The modular system design incorporates all wastewater streams and some food waste including urine water, hygiene water, humidity condensate, Sabatier water, fecal waste, laundry water, and organic food waste. These sources are fed simultaneously into the system, and a function-driven, sequential purification process occurs. The primary processes include carbon conversion, phase separation (solid/liquid/gas), disinfection, nutrient/salts management, and salts balancing to generate a clean water stream. The heart of the closed-loop bio-regenerative system is an anaerobic membrane bioreactor (AnMBR), which takes raw wastewater streams and utilizes an anaerobic microbial consortium to carry out the breakdown of the organic matter. An ultrafiltration membrane captures and destroys pathogenic bacteria and viruses. The AnMBR system generates a clean water stream containing fertilizer constituents which can be used to cultivate either microalgae (for food, pharma/nutraceuticals, fuel or bioplastics) in photobioreactors or crops in hydroponic systems. The system also generates methane and hydrogen gas which can be used for fuel (or conversion to bioplastics), and CO2 which can be used to support plant growth.

NASA's system was developed for smaller-scale, space-based applications. However, the technology is scalable for larger industrial and municipal water treatment applications. Implementation of the Ammonia Recovery System could significantly reduce nitrogen content from water treatment processes, meaningfully improving the quality of water. This system offers a novel way to reduce nitrogen water pollutants, while allowing for the nitrogen to be collected and reused- reducing environmental and public health risks and providing an environmentally friendly fertilizer option. NASAs environmental solutions work to sustain life on earth through space based technology The adaptable nature of this system gives it potentially broad applications in a wide variety of industries; it is particularly ideal for on-site remediation of wastewater in places like condo complexes, hotels and water parks. Current methods of ammonia recovery could not meet NASAs mission requirements, so a new process was devised to optimize for high ammonia selectivity, simplicity, low volume , low power usage and zero contaminants in the effluent. To do this, NASA designed a novel regenerable struvite-formation system for the capture of ammonia. This system has three primary functions: 1) Removal of ammonia from wastewater using a media that is highly selective for ammonia 2) Capture of the ammonia for later use (e.g., as a fertilizer) 3) Regeneration of the capture media for reuse in the system

The COSM employs NASA's Cryogenic Flux Capacitor core to store liquid oxygen (at 90 K) in silica aerogel material at ambient pressure, and then discharges cold oxygen gas into an in-line flow loop in response to heat input. If the composition of the incoming effluent stream contains gases with condensation or freezing points above the 90 K oxygen storage temperature--such as carbon dioxide or water vapor--these gasses can be removed from the stream as it moves through the COSM. The current COSM is sized to be wearable on the person but can be easily scaled to much larger sizes and various geometries. COSM is designed with a long "cold path" which provides for greater residence times which increase the probability that condensable/freezable gases will be trapped in the COSM. Also, the longer the cold path, the longer the time a COSM can be used prior to the oxygen being depleted and the scrubbed gasses liberated. Two COSM geometries have been designed, built, and tested-a round spiral and a prismatic serpentine--to achieve long cold paths, and intrinsic vapor cooling to manage heat loads.