Browsing by Author "Morse, Audra"
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Item Biologically Pre-Treated Habitation Waste Water as a Sustainable Green Urine Pre-Treat Solution(47th International Conference on Environmental Systems, 2017-07-16) Jackson, William; Thompson, Bret; Sevanthi, Ritesh; Morse, Audra; Meyer, Caitlin; Callahan, MichaelThe ability to recover water from urine and flush water is a critical process to allow long term sustainable human habitation in space or bases on the moon or mars. Organic N present as urea or similar compounds can hydrolyze producing free ammonia. This reaction results in an increase in the pH converting ammonium to ammonia which is volatile and not removed by distillation. The increase in pH will also cause precipitation reactions to occur. In order to prevent this urine on ISS is combined with a pretreat solution. While this process has been successful there are a number of draw backs including: storage and use of highly hazardous solutions, limitations on water recovery (<85%), and production of brine with pore dewatering characteristics. We evaluated the use of biologically treated habitation wastewaters (ISS and early planetary base) to replace the current pretreat solution. We evaluated both amended and un-amended bioreactor effluent. For the amended effluent we evaluated “green” pretreat chemicals including citric acid and citric acid amended with benzoic acid. We used a mock urine/air separator modeled after the urine collection assembly on ISS. The urine/air separator was challenged continually for ~6 months. Depending on the test point, the separator was challenged daily with donated urine and flushed with amended or un-amended reactor effluent. We monitored the pH of the urine, flush solution and residual pH in the urine/air separator after each urine event. We also evaluated solids production and biological growth. Our results support the use of both un-amended and amended bioreactor effluent to maintain the operability of the urine /air separator. The ability to use bioreactor effluent could decrease consumable cost, reduce hazards associated with current pre-treat chemicals, allow other membrane based desalination processes to be utilized, and improve brine characteristics.Item Environmental Characteristics of Traditional Construction and Maintenance Materials(Texas Department of Transportation, 2001-02) Mollhagen, Tony; Leggoe, Jeremy; Tock, Richard; Senadheera, Sanjaya; Nash, Phillip T.; Morse, AudraItem Further Investigations into the Performance of Membrane- Aerated Biological Reactors Treating a Space Based Waste Stream(45th International Conference on Environmental Systems, 2015-07-12) Christenson, Dylan; Sevanthi, Ritesh; Baldwin, Daniel; Morse, Audra; Jackson, W. Andrew; Meyer, Caitlin; Vega, Leticia; Pickering, Karen; Barta, DanielMembrane aerated biological reactors (MABR) have proven in terrestrial testing to be a sustainable and robust technology for treating space based waste streams that prove challenging for conventional systems due to high concentrations of carbon and nitrogen. Biological pretreatment stabilizes the waste stream without the use of harsh chemicals and also provides several distinct advantages including: 1) the conversion of NH3 to N2(gas), a required atmospheric component, or NOx species that are easily rejected by evaporative or membrane systems; 2) the transformation of organic matter to increase the efficiency of desalinization processes and produce a more stable waste product (brine); 3) the production of metabolic water; 4) the reduction in pH that facilitates membrane and distillation processes and reduces the required consumables and increases the life span of the processes; and 5) the potential elimination of the current hazardous pre-treat chemicals thereby producing a brine from which water can be recovered more easily. Work at both Texas Tech University (TTU) and Johnson Space Center (JSC) using the Counter-diffusion Membrane Aerated Nitrifying Denitrifying Reactor (CoMANDR) design has shown the ability of these systems to provide consistent and efficient carbon removal (>90%) and nitrification (>60%) when treating a space based waste stream consisting of urine, flush water, hygiene and laundry water, and humidity condensate. However, several areas were in need of further investigation. These include the ability of the system to handle on production urine feeding and the impact of membrane density on performance. The study of on production urine feeding allows us to determine the versatility of MABR bioreactors to a range of mission scenarios. Our past work has also identified operational issues for high density membrane modules in which the spacing between membranes is reduced. These high density modules can increase gas transfer but suffer from flow short circuiting due to biofilm bridging. We evaluated this relationship by operating MABRs with a range of specific surface areas and treating an Early Planetary Base waste stream.Item Handling Issues for Lead and Asbestos in Bridge Construction(Texas Department of Transportation, 2008-02) Taylor, Jedediah; Newhouse, Charles D.; Morse, AudraItem Handling Issues for Lead and Asbestos in Bridge Construction(Texas Department of Transportation, 2008-02-29) Taylor, Jed; Newhouse, Charles D.; Morse, AudraItem Investigations into the Performance of Membrane-Aerated Biological Reactors Treating a Space Based Waste Stream(46th International Conference on Environmental Systems, 2016-07-10) Sevanthi, Ritesh; Christenson, Dylan; Jackson, William; Morse, Audra; Meyer, Caitlin; Vega, Leticia; Shull, SarahTwo demonstration size membrane aerated biological reactors (MABR) CoMANDR 1.0 and CoMANDR 2.0 have previously demonstrated their ability to stabilize an early planetary base (EPB) waste stream over operating periods of ~1 year. Biological stabilization includes oxidation (>90%) of dissolved organic matter to CO2, partial conversion of organic N to NOx-, and reduced pH. Biological stabilization has a number of advantages including: 1) elimination of hazardous pre-treat chemicals; 2) production of N2(gas); 3) production of metabolic water; 3) a low pH effluent that facilitates membrane and distillation processes; and 4) a effluent that produces a better quality and less hazardous brine for water recovery. Preliminary analysis suggests that water recovery systems that integrated biological treatment may trade favorably compared to all physical/chemical systems. However, previous systems have incorporated reactor geometries and membrane specific surface areas which are not flight compatible. The R-CoMANDR (rectangular Counter-diffusion Membrane Aerated Nitrifying Denitrifying Reactor) system was developed to evaluate the ability of the smaller footprint reactor treat the range of possible waste streams (e.g. ISS to EPB) as well as the potential to operate without a feed tank. Individual waste streams (e.g. urine, hygiene, laundry, humidity condensate) are directly fed to the reactor on production. We will present performance data and evaluate the new flight like system design compared to previous systems.Item Long Term Biological Treatment of Space Habitation Waste Waters in a One Stage MABR: Comparison of Operation for N and C Oxidation With and Without Simultaneous Denitrification(48th International Conference on Environmental Systems, 2018-07-08) Sevanthi, Ritesh; Salehi Pourbavarsad, Maryam; Morse, Audra; Jackson, Andrew; Callahan, MichaelAerobic biological stabilization has been previously demonstrated for full size MABR’s (CoMANDR 1.0, CoMANDR 2.0, and R-CoMANDR) over operating periods of ~1 year. These systems have successfully treated a variety of possible habitation waste streams including an ISS (urine + flush and humidity condensate) and Early Planetary Base (EPB) wastewater (urine, flush water, hygiene wastewater, and laundry). Biological stabilization has a number of advantages including: 1) elimination of hazardous pre-treat chemicals; 2) production of NOx species (that can be easily rejected by evaporative or membrane systems); 3) elimination of volatile organic constituents; 4) a low pH effluent that facilitates membrane and distillation processes; and 5) an effluent that produces a better quality and less hazardous brine for water recovery. Previous work has primarily evaluated aerobic operation in which organic carbon and nitrogen is converted to CO2 and NOx-, respectively. An alternative to aerobic operation would be to include anoxic operation to promote denitrification and production of N2 gas. This allows for production of make-up gas as well as reduces the O2 demand and can increase ammonia oxidation efficiency. We evaluated the operation of a full scale (2 crew/day) MABR operated to perform oxidation of organic carbon and nitrogen with and without simultaneous reduction of oxidized N to N2 gas, simultaneous nitrification denitrification (SNDN). The system was challenged with a variety of space habitation wastewaters ranging from an ISS composition to a possible EPB waste stream under both continuous and on-production feeding modes. The system has been operated for over 2.5 years. We report on an overall comparison of aerobic oxidation and SNDN operational regimes to evaluate the system with the best overall attributes to support recycling of space habitation waste streams.Item Mind the gap: A process for diffusing innovative instructional strategies across STEM departments(2021-12) Cremeans, Lesley; McNaughtan, Jon; Paton, Valerie; Morse, AudraThe persistent gender gap across science, technology, engineering, and mathematics (STEM) education in the U.S. is a critical issue for the projected growth and innovation of STEM industries. Females earn a lower percentage of bachelor’s degrees across STEM academic fields compared to males. Federal and state agencies have released calls for proposals to support innovative instructional strategies in introductory STEM learning environments that are aimed at promoting student engagement. This call to action is important because the lowest rate of retention in undergraduate (UG) STEM education occurs during the first and second academic years. However, a large-scale adoption of innovative instructional strategies across introductory STEM education has been slow. Consequently, the gender gap remains persistent. Diffusion research suggests that the communication and social structures of an organization are systematic barriers that can impact the spread of information across an organization. The purpose of this qualitative case study is to explore a process for diffusing innovative instructional strategies to academic departments.Item Modification and assessment of a residential summer program for high school women(2018) Cloutier, Aimee; Zheng Yew, Guo (TTU); Gupta, Siddhartha (TTU); Dissanayake, Kalpani (TTU); Monaco, Paula; Mengel, Susan (TTU); Morse, AudraThe importance of reducing the gender gap in engineering programs by recruiting and retaining female students is well recognized. Although women hold roughly half of all jobs in the United States, only 24% of STEM jobs are occupied by women. The problem is even more pronounced for engineering, where women held about 12% of jobs as of 2013 (Corbett & Hill, 2015). Consequently, interactive, hands-on outreach programs are a common tool used by universities to encourage interest in engineering from K–12 students. Engineering—Get Into Real Learning (E-GIRL) is a week-long, residential summer program offered by Texas Tech University for female high school students. The primary goal of the program is to help participants make informed decisions about engineering majors and careers. To this aim, the purposes of the program are: (1) to offer a platform for female high school students to learn about the various disciplines of engineering offered at Texas Tech University and other universities; (2) to provide a realistic university experience, including coursework, social, and professional development opportunities; and (3) to provide hands-on exposure to a real-world engineering problem. E-GIRL ran for the second time in the summer of 2016, based on the favorable support it received in 2015. Primary components of this year’s program were a multidisciplinary group project focused on the theme of CO2 capture and storage, as well as a series of two-hour classes taught by university faculty and graduate students in the following six engineering disciplines: chemical engineering, civil engineering, environmental engineering, industrial engineering, mechanical engineering, and computer science. This paper presents the multidisciplinary structure of the program and its connection to the project that was assigned to program participants. The curriculum structure, the in-class activities, and the method of delivery for each discipline are explained in depth. The assessment of the program’s second year, including comparisons to the results from the first year and modifications to the program based on feedback from previous program participants, are discussed. Assessment was conducted through engineering skills assessment questionnaires, which required students to self-evaluate their competence in 18 skill sets before and after the program. These skill sets are qualities often identified to be important for engineers, and encompass traits associated with problem solving, project management, teamwork, and communication skills. Key results show improved self-assessment for most of the engineering skills after the program. Additionally, the skills that did not show improved self-assessment ratings after the program were consistent throughout both years. Qualitative results show a more matured and complete understanding of engineering and the individual engineering disciplines upon completion of the program. Through oral presentations, participants demonstrated in-depth engagement with the environmental conservation theme of the project. The environmental conservation theme is consistent with the participants’ aspirations for considering an engineering career and championing sustainability, which was highlighted by program participants in 2015 as a desired additional focus of the program. Overall, the program provided an opportunity for participants to experience the multidisciplinary nature of engineering, aided participants’ understanding of the roles of individual engineering disciplines, and furnished a realistic preview of student life in a university.Item Performance of a Full Scale MABR (CoMANDR 2.0) for Pre-treatment of a Habitation Waste Stream Prior to Desalination(44th International Conference on Environmental Systems, 2014-07-13) Sevanthi, Ritesh; Christenson, Dylan; Cummings, Elizabeth; Nguyen, Kevin; Morse, Audra; Jackson, W. AndrewRecycling waste water is a critical and crucial step to support sustainable long term habitation in space. Water is one of the largest contributors to the cost of space travel and the associated life support systems. In closed loop life support systems, membrane aerated biological reactors (MABRs) through biological reactions can reduce the dissolved organic carbon (DOC) and ammonia (NH3) concentration as well as decrease the pH of the waste water, leading to a more stable solution with less potential to support biological growth or promote carryover of un-ionized ammonia as well as producing a higher quality brine. We have previously demonstrated the successful performance over a 1 year period of a demonstration size MABR system, CoMANDR 1.0 (Counter-diffusion Membrane Aerated Nitrifying Denitrifying Reactor). This system was able to generally achieve DOC reductions of >90% and ammonium conversion rates of >50% over a range of loading rates. However, due to the very high specific surface area (SSA) (260 m2/m3) the system had poor hydraulic performance after one year of continual operation. The CoMANDR 2.0 system was developed to evaluate the impact of reduced specific surface area (200 m2/m3) as well as investigate the impact of low total air flow in to the system and forced hibernation periods (periods of no human habitation). The system was fed daily with un-stabilized wastewater composed of donated urine, ersatz hygiene water, humidity condensate, and laundry water. The liquid side system was continually monitored for pH, TDS, DO, and Temperature, and the influent and effluent monitored daily for DOC, TN, NOx, and NH4. The gas side system was continuously monitored for O2, CO2, and N2O was monitored intermittently in the effluent gas. Results support the ability of the system to effectively reduce organic carbon by over 90% and convert up to 70% of the total influent N to non-organic forms (e.g. NOx or N2). We have also demonstrated that for at least up to 4 weeks, CoMANDR may be placed in a recycle mode and can be brought back on line with no start up required supporting the ability to intermittently operate the system. Additionally, the system could handle low air and oxygen (80 mL/min) flow rates with a loading of 20 L/day and achieve high carbon removal.Item Transport Spill Containment for Texas Highways(Texas Department of Transportation, 2009-08-31) Morse, AudraItem A Two-Stage Biological Reactor for Treatment of Space Based Waste Waters(48th International Conference on Environmental Systems, 2018-07-08) Salehi Pourbavarsad, Maryam; Sevanthi, Ritesh; Ducon, Daniela; Morse, Audra; Jackson, Andrew; Callahan, MichaelPrevious works on Membrane Aerated Biological Reactors (MABR) CoMANDR 1.0, CoMANDR 2.0, and R-CoMANDAR have demonstrated their ability to stabilize various space based waste streams over operating periods of ~1 year. Biological stabilization includes reducing the pH, conversion of organic N to NOx- and oxidation of dissolved organic matter to CO2. These processes produce a more stable waste product (brine), facilitate distillation processes, and enable evaporative or membrane based systems. An alternative to aerobic operation would be to include anoxic operation to promote denitrification and production of N2 gas. This results in a reduced O2 demand and increases ammonia oxidation efficiency. Denitrification can be accomplished in either a single reactor (Simultaneous Nitrification Denitrification) or in a two-stage system with separate aerobic and anoxic reactors. We evaluated the performance of both architectures in pilot scale systems (1-2 crew/d). Each system was continuously operated for over 2 years during which they processed a variety of habitation waste streams including ISS (International Space Station), Transit, and EPB (Early Planetary Base) in both a continuous and on production feed mode. Here we report the results of the two stage system. Results indicate that the two stage system can successfully remove organic carbon, lower pH and convert organic N to N2 gas. Organic carbon and organic N oxidation reaction rates for the two stage system are similar to past studies for single stage aerobic systems. The two stage system is more complex and requires an additional pump. While no maintenance was required on the system during the nearly two year period of operation, the packed bed did produce N2 gas for many operational test points. The performance and comparison of operational conditions are detailed below.Item Use of Alternative Water Sources(Texas Department of Transportation, 2005-10) Rajagopalan, Srinath; Morse, Audra; Fedler, Clifford; Jackson, Andrew; Jayawickrama, PriyanthaItem WRC Newsletter (Feb 2002)(Water Resources Center, 2002-02) Morse, AudraItem WRC Newsletter (Oct 2001)(Water Resources Center, 2001-10) Jackson, Andrew; Thompson, David; Morse, Audra; Crabtree, Greg; Rainwater, Ken