Browsing by Author "Snyder, Sarah"
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Item ISS Waste Water Pretreatment Via DNA Pattern Picofilter Using Inorganic Brine Simulant(50th International Conference on Environmental Systems, 7/12/2021) Franco, Carolina; Lunn, Griffin; Snyder, Sarah; Link, Bruce; Melendez, Orlando; Dominguez, JesusAstronauts in the International Space Station need as much water as they can access, whether it comes from people's breath, sweat or urine, recycled shower water or from hand-washing. It is of vital importance that any type of water gets recycled and filtrated through different methods so it can be re-used. Recently, a company called Cerahelix, Inc. offered a ceramic tubular membrane element that uses DNA strands as a pattern in a sol-gel process that allows the sintered product to have a pore size in the picometer scale and claims to achieve ten times higher purity than other commercially available ceramic filters. This should allow higher purities and yields at reduced energy costs and theoretically allow near total dewatering of the reject stream and 80%+ polyvalent ion removal. A triplicate set of tests at two different pHs were performed with Cerahelix filters using an inorganic brine simulant in order to test and evaluate the efficiency of its PicoHelixTM membrane and determine feasibility for spacecraft and similar wastewater pretreatment processes. Several ions were studied but emphasis was placed on the polyvalent ions, SO42-, PO43-, Mg2+, and Ca2+; these ions should be rejected almost entirely from the feed solution and, therefore, the masses for the corresponding ions would be as close to zero as the feed permeates through the filter. Initial test results show that at a pH of 4.2, permeation of the polyvalent ions vary from 59% to 74% and at pH of 8.0 permeates vary from 72% to 87%, a very small amount was retained in the reject. Extended Nernst Planck (ENP) approach that describes the mass transfer process in the pico-filtration membranes was used to build a model and be able to explain the experimental outcome.Item Wastewater Brine Purification and Recovery through Electrodialysis Ion Exchange(50th International Conference on Environmental Systems, 7/12/2021) Hancock, Matthew; Snyder, Sarah; Hintze, PaulReutilizing resources onboard the International Space Station (ISS) and for future deep space missions are critical for mission longevity and sustainability. Wastewater brine produced from water recovery systems contain chemical species that could be processed into a potential fertilizer for future plant systems. This can be achieved through a process called electrodialysis ion exchange. Wastewater containing inorganic salt components are fed through a series of ion exchange membranes to produce fertilizer (a phosphate rich stream), electrolysis-grade water, and other useful commodities. Electrodialysis cells consisting of anion and cation exchange membranes, monovalent anion exchange membranes, and bipolar membranes were utilized to achieve selective ion exchange. The use of the electrodialysis cells were effective for both water extraction and ion separation. Ions successfully diffused across their respective membranes into the concentrate, acid, and base streams. This resulted in pure water, a phosphate rich stream, and a separate anion/hydrogen and cation/hydroxide stream. However, sulfate and some phosphate ions were able to diffuse through the monovalent anion exchange membrane into the acid stream. This resulted in predominantly phosphate ions remaining in the concentrate. Optimization of the process was accomplished by altering flowrates of each stream and initial volumes, adjusting the power input and resulting current through each cell, and varying the starting parameters by splitting the inorganic waste input into the diluate and the concentrate. As expected, increasing the flowrate and the power input to each cell reduced the overall time of the process. However, mission constraints may require a longer duration process in order to reduce the power consumption. Further analysis will be required to determine the power input necessary to achieve ion diffusion effectively and in a timely manner.