Browsing by Author "Goeres, Darla"
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Item Analysis of CDC Bioreactor Internal Thermal Measurements and Sample Coupon Temperatures(2023 International Conference on Environmental Systems, 2023-07-16) Beitle, Eric; Murphy, Connor; Velez Justiniano, Yo-Ann; Goeres, DarlaThe Center for Disease Control and Prevention (CDC) bioreactor is an integral laboratory tool for the Environmental Control and Life Support Systems (ECLSS) biofilm formation and growth research program. Critical to this research is the need to adjust and maintain various surface temperatures of the coupons housed within the CDC Bioreactor. The purpose of this study was to provide quantitative temperature gradient information when the CDC Bioreactor was operating according to several process scenarios. Two primary process parameters were evaluated. For the first set of test parameters, the liquid level was maintained at 350 mL, with an inlet flowrate of 0.1 mL/min, 1 mL/min, 10 mL/min. The liquid was allowed to gravity drain out of the outlet spout. For the second set of test parameters, the liquid level within the reactor was maintained at 550 mL, with an inlet flow of 0.1 mL/min, 1 mL/min, 10mL/min and draining intermittently controlled to 0.8 mL/min to maintain the 550 mL level. Due to the placement of the thermocouple in the reactor, a difference in temperature occurred between the coupon surfaces and target Bioreactor temperature when operated according to the first set of test parameters. When the reactor was operated according to the second set of parameters, which resulted in the thermocouple being submerged, the temperature gradient was eliminated. The results demonstrated minimal temperature gradient between the top and bottom coupon surfaces for coupons placed in a single rod within the CDC Bioreactor for both sets of test parameters evaluated. The collection of this information helped to explain previous ECLSS biofilm formation test runs, along with providing guidance on best operating practices for future ECLSS experiments. The placement of the thermocouple also helps to explain the challenge of achieving and maintaining bulk liquid temperatures when biofilm is grown according to the standardized methods.Item Biofilm Management in a Microgravity Water Recovery System(50th International Conference on Environmental Systems, 7/12/2021) Velez Justiniano, Yo-Ann; Carter, Donald; Sandvik, Elizabeth; Stewart, Phil; Goeres, Darla; Sturman, Paul; Li, Wenyan; Johnson, Alexander; Cioanta, IulianBiofilm growth continues to be a significant concern for NASA�s current and future water systems. The International Space Station (ISS) Water Processor Assembly (WPA) produces potable water from a combination of humidity condensate and urine distillate. The WPA waste tank requires significant management to prevent biofilm growth from impacting downstream components. This issue is magnified for future NASA manned missions due to the need to place the vehicle�s life support system in a dormant state during uncrewed operations (e.g., when vehicle is in Mars orbit during surface mission). NASA personnel and the Center for Biofilm Engineering at Montana State University are evaluating various methods for mitigating biofilm growth, including reduced nutrient levels, thermal treatment, ultrasonic treatment, and identifying effective biocides in this application. This paper provides an overview of the current status on this effort.