The purpose of this investigation is to explore the capabilities of a dialysis-membrane-based system for the in-line dosing of silver ions to treated water in spacecraft water recovery units. The spacecraft environmental control and life support system community (ECLSS) are interested in adopting silver ions as a biocide in future spacecraft water recovery processes since silver ions are effective biocide at concentrations that humans can safely consume. The system has been designed following the configuration of the Water Processor Assembly (WPA) aboard the International Space Station. In this configuration, silver ions have to be added at the last step in the WPA to inhibit the growth of microorganisms in the product water. The dialysis-membrane-based system has to supply silver ions into the potable water at concentrations ranging from 200 to 400 parts per billion during the entire water processing time. The silver ion delivery system has been prototyped by repurposing dialysis membranes used for the separation/purification of low molecular weight solutes. Consequently, the low molecular weight cutoff of the dialysis membrane controls the silver ion release from a concentrated silver ion reservoir and does not require any power. Both computational and experimental studies were conducted to examine the performance of the silver ion delivery and the feasibility of integrating this technology in future spacecraft water recovery units. The preliminary results from this investigation show that the dialysis-membrane-based passive biocide delivery system can supply sufficient silver ions to a stream of deionized water. Nevertheless, the outflow might require dilution, and the membrane may need to undergo preconditioning for optimal performance, especially for reuse.
","abstract_html":"<p>The purpose of this investigation is to explore the capabilities of a dialysis-membrane-based system for the in-line dosing of silver ions to treated water in spacecraft water recovery units. The spacecraft environmental control and life support system community (ECLSS) are interested in adopting silver ions as a biocide in future spacecraft water recovery processes since silver ions are effective biocide at concentrations that humans can safely consume. The system has been designed following the configuration of the Water Processor Assembly (WPA) aboard the International Space Station. In this configuration, silver ions have to be added at the last step in the WPA to inhibit the growth of microorganisms in the product water. The dialysis-membrane-based system has to supply silver ions into the potable water at concentrations ranging from 200 to 400 parts per billion during the entire water processing time. The silver ion delivery system has been prototyped by repurposing dialysis membranes used for the separation/purification of low molecular weight solutes. Consequently, the low molecular weight cutoff of the dialysis membrane controls the silver ion release from a concentrated silver ion reservoir and does not require any power. Both computational and experimental studies were conducted to examine the performance of the silver ion delivery and the feasibility of integrating this technology in future spacecraft water recovery units. The preliminary results from this investigation show that the dialysis-membrane-based passive biocide delivery system can supply sufficient silver ions to a stream of deionized water. Nevertheless, the outflow might require dilution, and the membrane may need to undergo preconditioning for optimal performance, especially for reuse.</p>","abstract_has_math":false,"creators":["Garcia Fernandez, Rogelio Elias"],"institution":null,"degree_name":"Master of Science in Chemical Engineering (MSChE)","degree_level":"Thesis","degree_discipline":null,"degree_department":null,"school":null,"contributors":["Wickramasinghe, S. Ranil","Roe, Larry A."],"advisors":["Beitle, Robert R. Jr."],"committee_chairs":[],"committee_members":[],"year":2021,"date_issued":"2021-12-01T08:00:00Z","date_published":"2021-12-01T08:00:00Z","updated_at":"2026-07-24T00:59:08Z","subjects":["biocide dosing system","long-term space mission","silver biocide","space exploration","spacecraft water management","water recovery system","Aerodynamics and Fluid Mechanics","Space Vehicles","Transport Phenomena"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://scholarworks.uark.edu/etd/4322","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Wickramasinghe, S. Ranil","Roe, Larry A."]},{"key":"dc:contributor.advisor","label":"Advisor","values":["Beitle, Robert R. Jr."]},{"key":"dc:creator","label":"Author","values":["Garcia Fernandez, Rogelio Elias"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2021"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2022-05-13T07:00:00Z"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Thesis"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science in Chemical Engineering (MSChE)"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["biocide dosing system","long-term space mission","silver biocide","space exploration","spacecraft water management","water recovery system","Aerodynamics and Fluid Mechanics","Space Vehicles","Transport Phenomena"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://scholarworks.uark.edu/etd/4322"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["The purpose of this investigation is to explore the capabilities of a dialysis-membrane-based system for the in-line dosing of silver ions to treated water in spacecraft water recovery units. The spacecraft environmental control and life support system community (ECLSS) are interested in adopting silver ions as a biocide in future spacecraft water recovery processes since silver ions are effective biocide at concentrations that humans can safely consume. The system has been designed following the configuration of the Water Processor Assembly (WPA) aboard the International Space Station. In this configuration, silver ions have to be added at the last step in the WPA to inhibit the growth of microorganisms in the product water. The dialysis-membrane-based system has to supply silver ions into the potable water at concentrations ranging from 200 to 400 parts per billion during the entire water processing time. The silver ion delivery system has been prototyped by repurposing dialysis membranes used for the separation/purification of low molecular weight solutes. Consequently, the low molecular weight cutoff of the dialysis membrane controls the silver ion release from a concentrated silver ion reservoir and does not require any power. Both computational and experimental studies were conducted to examine the performance of the silver ion delivery and the feasibility of integrating this technology in future spacecraft water recovery units. The preliminary results from this investigation show that the dialysis-membrane-based passive biocide delivery system can supply sufficient silver ions to a stream of deionized water. Nevertheless, the outflow might require dilution, and the membrane may need to undergo preconditioning for optimal performance, especially for reuse.
"]},{"key":"dc:title","label":"Title","values":["Preliminary Development of The Dialysis-Membrane-based Passive Biocide Delivery System for Spacecraft Water Recovery Units"]}]}],"canonical_facts":{"dc:contributor":["Wickramasinghe, S. Ranil","Roe, Larry A."],"dc:contributor.advisor":["Beitle, Robert R. Jr."],"dc:creator":["Garcia Fernandez, Rogelio Elias"],"dc:date":["2021"],"dc:date.available":["2022-05-13T07:00:00Z"],"dc:description.abstract":["The purpose of this investigation is to explore the capabilities of a dialysis-membrane-based system for the in-line dosing of silver ions to treated water in spacecraft water recovery units. The spacecraft environmental control and life support system community (ECLSS) are interested in adopting silver ions as a biocide in future spacecraft water recovery processes since silver ions are effective biocide at concentrations that humans can safely consume. The system has been designed following the configuration of the Water Processor Assembly (WPA) aboard the International Space Station. In this configuration, silver ions have to be added at the last step in the WPA to inhibit the growth of microorganisms in the product water. The dialysis-membrane-based system has to supply silver ions into the potable water at concentrations ranging from 200 to 400 parts per billion during the entire water processing time. The silver ion delivery system has been prototyped by repurposing dialysis membranes used for the separation/purification of low molecular weight solutes. Consequently, the low molecular weight cutoff of the dialysis membrane controls the silver ion release from a concentrated silver ion reservoir and does not require any power. Both computational and experimental studies were conducted to examine the performance of the silver ion delivery and the feasibility of integrating this technology in future spacecraft water recovery units. The preliminary results from this investigation show that the dialysis-membrane-based passive biocide delivery system can supply sufficient silver ions to a stream of deionized water. Nevertheless, the outflow might require dilution, and the membrane may need to undergo preconditioning for optimal performance, especially for reuse.
"],"dc:identifier":["https://scholarworks.uark.edu/etd/4322"],"dc:subject":["biocide dosing system","long-term space mission","silver biocide","space exploration","spacecraft water management","water recovery system","Aerodynamics and Fluid Mechanics","Space Vehicles","Transport Phenomena"],"dc:title":["Preliminary Development of The Dialysis-Membrane-based Passive Biocide Delivery System for Spacecraft Water Recovery Units"],"thesis:degree_level":["Thesis"],"thesis:degree_name":["Master of Science in Chemical Engineering (MSChE)"]},"updated_at":"2026-07-24T00:59:08Z"}