Browsing by Author "Lunn, Griffin M."
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Item Analysis of Process Gases and Trace Contaminants in Membrane-Aerated Gaseous Effluent Streams(45th International Conference on Environmental Systems, 2015-07-12) Coutts, Janelle L.; Lunn, Griffin M.; Vega, Leticia M.; Meyer, CaitlinIn membrane-aerated biofilm reactors (MABRs), hollow fibers are used to supply oxygen to the biofilms and bulk fluid. A pressure and concentration gradient between the inner volume of the fibers and the reactor reservoir drives oxygen mass transport across the fibers toward the bulk solution, providing the fiber-adhered biofilm with oxygen. Conversely, bacterial metabolic gases from the bulk liquid, as well as from the biofilm, move opposite to the flow of oxygen, entering the hollow fiber and out of the reactor. Metabolic gases are excellent indicators of biofilm vitality, and can aid in microbial identification. Certain gases can be indicative of system perturbations and control anomalies, or potentially unwanted biological processes occurring within the reactor. In confined environments, such as those found during spaceflight, it is important to understand what compounds are being stripped from the reactor and potentially released into the crew cabin to determine the appropriateness or the requirement for additional mitigation factors. Reactor effluent gas analysis focused on samples provided from Kennedy Space Center’s sub-scale MABRs, as well as Johnson Space Center’s full-scale MABRs, using infrared spectroscopy and gas chromatography techniques. Process gases, such as carbon dioxide, oxygen, nitrogen, nitrogen dioxide, and nitrous oxide, were quantified to monitor reactor operations. Solid Phase Microextraction (SPME) GC-MS analysis was used to identify trace volatile compounds. Compounds of interest were subsequently quantified. Reactor supply air was examined to establish target compound baseline concentrations. Concentration levels were compared to average ISS concentration values and/or Spacecraft Maximum Allowable Concentration (SMAC) levels where appropriate. Based on a review of to-date results, current trace contaminant control systems (TCCS) currently on board the ISS should be able to handle the added load from bioreactor systems without the need for secondary mitigation.Item Dormancy and Recovery Testing for Biological Wastewater Processors(45th International Conference on Environmental Systems, 2015-07-12) Hummerick, Mary E.; Coutts, Janelle L.; Lunn, Griffin M.; Spencer, LaShelle; Khodadad, Christina L.; Birmele, Michele N.; Frances, Someliz; Wheeler, RaymondBioreactors, such as the aerated hollow fiber membrane type, have been proposed and studied for a number of years as an alternate approach for treating wastewater streams for space exploration. Several challenges remain to be resolved before these types of bioreactors can be used in space settings, including transporting the bioreactors with intact and active biofilms, whether that be to the International Space Station or beyond, or procedures for safing the systems and placing them into a dormant state for later start-up. Little information is available on such operations as it is not common practice for terrestrial systems. This study explored several dormancy processes for established bioreactors to determine optimal storage and recovery conditions. Procedures focused on complete isolation of the microbial communities from an operational standpoint and observing the effects of: 1) storage temperature, and 2) storage with or without the reactor bulk fluid. The first consideration was tested from a microbial integrity and power consumption standpoint; both ambient temperature (25°C) and cold (4°C) storage conditions were studied. The second consideration was explored; again, for microbial integrity as well as plausible real-world scenarios of how terrestrially established bioreactors would be transported to microgravity and stored for periods of time between operations. Biofilms were stored without the reactor bulk fluid to simulate transport of established biofilms into microgravity, while biofilms stored with the reactor bulk fluid simulated the most simplistic storage condition to implement operations for extended periods of nonuse. Dormancy condition did not have an influence on recovery in initial studies with immature biofilms (48 days old), however a lengthy recovery time was required (20+ days). Bioreactors with fully established biofilms (13 months) were able to recover from a 7-month dormancy period to steady state operation within 4 days (~1 residence cycle). Results indicate a need for future testing on biofilm age and health and further exploration of dormancy length.Item Hollow Fiber Membrane Bioreactor Systems for Wastewater Processing: Effects of Environmental Stresses Including Dormancy Cycling and Antibiotic Dosing(46th International Conference on Environmental Systems, 2016-07-10) Coutts, Janelle; Hummerick, Mary; Lunn, Griffin M.; Larson, Brian; Spencer, Lashelle; Kosiba, Michael; Khodadad, Christina; Catechis, JohnHollow fiber membrane bioreactors (HFMBs) have been studied for a number of years as an alternate approach for treating wastewater streams during space exploration. While the technology provides a promising pre-treatment for lowering organic carbon and nitrogen content without the need for harsh stabilization chemicals, several challenges must be addressed before adoption of the technology in future missions. One challenge is the transportation of bioreactors containing intact, active biofilms as a means for rapid start-up on the International Space Station or beyond. Similarly, there could be a need for placing these biological systems into a dormant state for extended periods when the system is not in use, along with the ability for rapid restart. Previous studies indicated that there was little influence of storage condition (4 or 25ºC, with or without bulk fluid) on recovery of bioreactors with immature biofilms (48 days old), but that an extensive recovery time was required (20+ days). Bioreactors with fully established biofilms (13 months) were able to recover from a 7-month dormancy within 4 days (~1 residence). Further dormancy and recovery testing is presented here that examines the role of biofilm age on recovery requirements, repeated dormancy cycle capabilities, and effects of long-duration dormancy cycles (8-9 months) on HFMB systems. Another challenge that must be addressed is the possibility of antibiotics entering the wastewater stream. Currently, for most laboratory tests of biological water processors, donors providing urine may not contribute to the study when taking antibiotics because the effects on the system are yet uncharacterized. A simulated urinary tract infection event, where an opportunistic, pathogenic organism, E. coli, was introduced to the HFMBs followed by dosing with an antibiotic, ciprofloxacin, was completed to study the effect of the antibiotic on reactor performance and to also examine the development of antibiotic-resistant communities within the system.Item Next Generation Life Support Project Status(44th International Conference on Environmental Systems, 2014-07-13) Barta, Daniel J.; Chullen, Cinda; Vega, Leticia; Cox, Marlon R.; Aitchison, Lindsay T.; Lange, Kevin E.; Pensinger, Stuart J.; Meyer, Caitlin E.; Flynn, Michael; Richardson, Tra-My Justine; Jackson, W. Andrew; Abney, Morgan B.; Birmele, Michele N.; Lunn, Griffin M.; Wheeler, Raymond M.Next Generation Life Support (NGLS) is one of more than 20 technology development projects sponsored by NASA’s Game Changing Development Program. The NGLS Project develops selected life support technologies needed for humans to live and work productively in space, with focus on technologies for future use in spacecraft cabin and space suit applications. Over the last 3 years, NGLS had five main project elements: Variable Oxygen Regulator (VOR), Rapid Cycle Amine (RCA) swing bed, High Performance Extravehicular Activity (EVA) Glove (HPEG), Alternative Water Processor (AWP) and Series-Bosch Carbon Dioxide Reduction. The RCA swing bed, VOR and HPEG tasks are directed at key technology needs for the Portable Life Support System (PLSS) and pressure garment for an Advanced Extravehicular Mobility Unit (EMU). Focus is on prototyping and integrated testing in cooperation with the Advanced Exploration Systems (AES) Advanced EVA Project. The HPEG Element, new this fiscal year, includes the generation of requirements and standards to guide development and evaluation of new glove designs. The AWP and Bosch efforts focus on regenerative technologies to further close spacecraft cabin atmosphere revitalization and water recovery loops and to meet technology maturation milestones defined in NASA’s Space Technology Roadmaps. These activities are aimed at increasing affordability, reliability, and vehicle self-sufficiency while decreasing mass and mission cost, supporting a capability-driven architecture for extending human presence beyond low-Earth orbit, along a human path toward Mars. This paper provides a status of current technology development activities with a brief overview of future plans.Item A novel ion exchange system to purify mixed ISS waste water brines for chemical production and enhanced water recovery(44th International Conference on Environmental Systems, 2014-07-13) Lunn, Griffin M.; Spencer, LaShelle E.; Ruby, Anna Maria J.; McCaskill, AndrewThe International Space Station water recovery system produces a sizable portion of waste water brine. This brine is highly toxic and contains a significant volume of water. With new biological techniques that do not require waste water chemical pretreatment, the resulting brine would be chromium-free, nitrate rich, and could be used for fertilizer recovery in future plant systems. Using a system of ion exchange resins may remove hardness, sulfate, phosphate and nitrate from these brines leaving only sodium and potassium chloride. At this point modern chlor-alkali cells can be utilized to produce a low salt stream as well as an acid and base stream. The first stream (low salt) can be used to gain higher water recovery through recycle to the water separation stage while the last two streams can be used to regenerate the ion exchange beds used here, as well as other ion exchange beds in the ISS. Conveniently these waste products from ion exchange regeneration would be suitable as plant fertilizer. In this report the performance of state of the art resins designed for high selectivity of target ions under brine conditions was determined. Using ersatz ISS waste water we can evaluate the performance of specific resins and calculate mass balances to determine resin effectiveness and process viability. If this system is feasible then we will be one step closer to closed loop environmental control and life support systems (ECLSS) for current or future applications.Item Self-Cleaning Boudouard Reactor for Full Oxygen Recovery from Carbon Dioxide(46th International Conference on Environmental Systems, 2016-07-10) Hintze, Paul E.; Muscatello, Anthony C.; Gibson, Tracy L.; Captain, James G.; Lunn, Griffin M.; Devor, Robert W.; Bauer, Brint; Parks, SteveOxygen recovery from respiratory carbon dioxide is an important aspect of human spaceflight. Methods exist to sequester the carbon dioxide, but production of oxygen needs further development. The current International Space Station Carbon Dioxide Reduction System (CRS) uses the Sabatier reaction to produce water (and ultimately breathing air). Oxygen recovery is limited to 50% because half of the hydrogen used in the Sabatier reactor is lost as methane, which is vented overboard. The Bosch reaction, which converts carbon dioxide to oxygen and solid carbon is capable of recovering all the oxygen from carbon dioxide, and is a promising alternative to the Sabatier reaction. However, the last reaction in the cycle, the Boudouard reaction, produces solid carbon and the resulting carbon buildup eventually fouls the nickel or iron catalyst, reducing reactor life and increasing consumables. To minimize this fouling and increase efficiency, a number of self-cleaning catalyst designs have been created. This paper will describe recent results evaluating the designs.Item Sodium Chloride Removal from International Space Station Wastewater Brine to Generate Plant Fertilizer(50th International Conference on Environmental Systems, 7/12/2021) Irwin, Tesia; Diaz, Angie; Li, Wenyan; Lunn, Griffin M.; Koss, Lawrence; Wheeler, Raymond; Callahan, Michael; Jackson, Andrew; Calle, Luz M.Water is a critical resource for human exploration beyond low earth orbit. There are two general mechanisms for wastewater recovery. The current practice on the International Space Station (ISS) is vapor compression distillation, which requires a significant amount of consumables and has a water recovery rate of around 75%. An alternative approach is a biological water processor (BWP), integrated with a forward osmosis secondary treatment system (FOST). The integrated system is expected to recover 95% of the initial wastewater volume. The remaining 5% is lost as a concentrated brine. For a closed-loop water recovery system, all nutrients should be recovered and reused. For far-term life support, plant systems will be introduced to grow in situ foods, as well as to regenerate O2 and remove CO2 from cabin air. To do so will require a continuous flow of nutrients or fertilizer. The wastewater brine provides a rich source of nutrients for plants, but its high sodium content presents a challenge for most food crops. Direct recycling of urine to crops for life support was tested in Bios-3 (Russia) and resulted in salinization of growth systems. Halophytic plants have been tested with high Na inputs but their yields are low. A thermal swing process has been proposed to separate NaCl from other salts in wastewater for use as plant fertilizer. The paper reports the initial proof of concept testing results, which showed that the thermal swing process is a promising approach for NaCl reduction from wastewater, as well as the tasks planned for further development.