{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/137702"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/137702","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"Assessment of a Passive Sampler for Aquifer Microbial Community Profiling and Comparison of Porous Media","abstract":"Managed aquifer recharge (MAR) with advanced treated wastewater is a promising strategy to combat aquifer depletion; however, its impact on native microbial communities remains insufficiently characterized. Concerns include the potential introduction of pathogens, antibiotic resistance genes (ARGs), and trace organic pollutants, as well as the disruption of native microbial processes critical for contaminant degradation in groundwater. However, it is very challenging to sample aquifer microbes in situ, especially in a representative, time-resolved fashion. With this goal, we developed a passive sampler that employs removable cartridges containing solid media designed to re-create the aquifer environment in a controlled fashion and support consistent, repeatable, time-series sampling. A bench-scale, continuous-loop study compared microbial community dynamics across three candidate porous media: native aquifer sediment, zirconia beads, and laboratory-grade silica sand. 16S rRNA gene amplicon sequencing was applied to profile microbial communities and revealed that native aquifer sediment from the aquifer of study best reflected influent microbial composition and temporal shifts, particularly among the dominant bacterial phyla Proteobacteria, Bacteroidota, Planctomycetota, and Verrucomicrobiota. Native sediment also exhibited more spatial consistency in microbial diversity. Based on these findings, a full-scale, 3Dprinted sampler using native sediment was developed for long-term monitoring in MAR systems to support future study of the impacts of introduction of advanced treated water into an aquifer.","abstract_html":"Managed aquifer recharge (MAR) with advanced treated wastewater is a promising strategy to combat aquifer depletion; however, its impact on native microbial communities remains insufficiently characterized. Concerns include the potential introduction of pathogens, antibiotic resistance genes (ARGs), and trace organic pollutants, as well as the disruption of native microbial processes critical for contaminant degradation in groundwater. However, it is very challenging to sample aquifer microbes in situ, especially in a representative, time-resolved fashion. With this goal, we developed a passive sampler that employs removable cartridges containing solid media designed to re-create the aquifer environment in a controlled fashion and support consistent, repeatable, time-series sampling. A bench-scale, continuous-loop study compared microbial community dynamics across three candidate porous media: native aquifer sediment, zirconia beads, and laboratory-grade silica sand. 16S rRNA gene amplicon sequencing was applied to profile microbial communities and revealed that native aquifer sediment from the aquifer of study best reflected influent microbial composition and temporal shifts, particularly among the dominant bacterial phyla Proteobacteria, Bacteroidota, Planctomycetota, and Verrucomicrobiota. Native sediment also exhibited more spatial consistency in microbial diversity. Based on these findings, a full-scale, 3Dprinted sampler using native sediment was developed for long-term monitoring in MAR systems to support future study of the impacts of introduction of advanced treated water into an aquifer.","abstract_has_math":false,"creators":["Riddley, Mia Raye"],"institution":"Virginia Tech","degree_name":"Master of Science","degree_level":"masters","degree_discipline":"Civil Engineering","degree_department":"Civil and Environmental Engineering","school":null,"contributors":[],"advisors":[],"committee_chairs":["Liao, Jingqiu","Pruden, Amy"],"committee_members":["Schreiber, Madeline E."],"year":2025,"date_issued":"2025-07-14","date_published":"2025-07-14","updated_at":"2026-07-22T22:19:41Z","subjects":["Managed aquifer recharge","soil aquifer treatment","passive sampler","microbial dynamics monitoring","water reclamation/reuse"],"languages":[],"rights":["In Copyright"],"rights_urls":["http://rightsstatements.org/vocab/InC/1.0/"],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/10919/137702","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.committeechair","label":"Committee Chair","values":["Liao, Jingqiu","Pruden, Amy"]},{"key":"dc:contributor.committeemember","label":"Committee Member","values":["Schreiber, Madeline E."]},{"key":"dc:contributor.department","label":"Department","values":["Civil and Environmental Engineering"]},{"key":"dc:creator","label":"Author","values":["Riddley, Mia Raye"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2025-09-09T19:38:15Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2025-09-09T19:38:15Z"]},{"key":"dc:date.issued","label":"Date","values":["2025-07-14"]},{"key":"dc:publisher","label":"Institution","values":["Virginia Tech"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"dc:type.dcmitype","label":"Dc Type Dcmitype","values":["Text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Civil Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["masters"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Virginia Polytechnic Institute and State University"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Managed aquifer recharge","soil aquifer treatment","passive sampler","microbial dynamics monitoring","water reclamation/reuse"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:rights","label":"Dc Rights","values":["In Copyright"]},{"key":"dc:rights.uri","label":"Rights URI","values":["http://rightsstatements.org/vocab/InC/1.0/"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://hdl.handle.net/10919/137702"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Managed aquifer recharge (MAR) with advanced treated wastewater is a promising strategy to combat aquifer depletion; however, its impact on native microbial communities remains insufficiently characterized. Concerns include the potential introduction of pathogens, antibiotic resistance genes (ARGs), and trace organic pollutants, as well as the disruption of native microbial processes critical for contaminant degradation in groundwater. However, it is very challenging to sample aquifer microbes in situ, especially in a representative, time-resolved fashion. With this goal, we developed a passive sampler that employs removable cartridges containing solid media designed to re-create the aquifer environment in a controlled fashion and support consistent, repeatable, time-series sampling. A bench-scale, continuous-loop study compared microbial community dynamics across three candidate porous media: native aquifer sediment, zirconia beads, and laboratory-grade silica sand. 16S rRNA gene amplicon sequencing was applied to profile microbial communities and revealed that native aquifer sediment from the aquifer of study best reflected influent microbial composition and temporal shifts, particularly among the dominant bacterial phyla Proteobacteria, Bacteroidota, Planctomycetota, and Verrucomicrobiota. Native sediment also exhibited more spatial consistency in microbial diversity. Based on these findings, a full-scale, 3Dprinted sampler using native sediment was developed for long-term monitoring in MAR systems to support future study of the impacts of introduction of advanced treated water into an aquifer."]},{"key":"dc:description.abstractgeneral","label":"General Abstract","values":["Though more of the earth is covered in water in comparison to land, only a small portion of this water is drinkable and can sustain human life. It is important to acknowledge that water operates in a “circle of life”, whereas no water is new water. Every drop of water we use to drink or even flush our toilets has been cycled through every phase of life. Therefore, it is imperative that we preserve the drinking water resources that we have, as we embrace the challenges of providing sustainable freshwater resources in the face of climate change and increased water demand. One way that we are able to do this is through managed aquifer recharge (MAR) into groundwater, which is a vital source of drinking water that is under severe pressure across the United States. Groundwater provides nearly half of the domestic water use in the U.S, including both private and public well supplies. MAR technologies work to address the growing water concerns by taking highly treated wastewater and pumping it into groundwater systems, which allows us to store water for later consumption. MAR helps prevent problems like land subsidence and supports long-term use of water for drinking, farming, and other needs. However, there are still important questions about how this practice affects subsurface ecosystems, particularly the microbial communities that naturally exist in groundwater. The use of this technology has been popularized around the world and within the U.S. there are 36 states as of 2020 using MAR. With the growing usage, there is an important to have a comprehensive understanding of the effects of using MAR for both human and environmental health today and in the future. Such effects could be on both “bad” microbes, which cause disease, and “good” microbes, which can help to biodegrade pollutants in the environment. MAR could accidentally introduce pathogens or antibiotic resistance genes (ARGs) into these systems, while on the other hand, enhancing the diversity of microbes capable of further breaking down any residual pollutants in the MAR water. To study these effects, scientists need ways to collect microbial samples over time without disturbing the aquifer environment. To address this, we developed a passive sampler that mimics natural aquifer conditions and allows for periodic collection of microbes. In a controlled lab experiment, we tested three materials inside the sampler: native aquifer sediment, zirconia beads, and sand to see which best captured changes in microbial communities over time. Using DNA sequencing, we found that the sediment was the most effective. It captured a more stable and representative picture of the microbial community, especially over time, and showed similarities to the microbes present in the surrounding water. Based on these findings, we created a full-scale version of the passive sampler using 3D printing and sediment as the core material. This tool can now be used in MAR systems to monitor microbial changes. Understanding these changes is essential for ensuring that MAR is not only effective but also safe for the environment and public health."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Master of Science"]},{"key":"dc:format.medium","label":"Dc Format Medium","values":["ETD"]},{"key":"dc:format.mimetype","label":"Dc Format Mimetype","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Assessment of a Passive Sampler for Aquifer Microbial Community Profiling and Comparison of Porous Media"]}]}],"canonical_facts":{"dc:contributor.committeechair":["Liao, Jingqiu","Pruden, Amy"],"dc:contributor.committeemember":["Schreiber, Madeline E."],"dc:contributor.department":["Civil and Environmental Engineering"],"dc:creator":["Riddley, Mia Raye"],"dc:date.accessioned":["2025-09-09T19:38:15Z"],"dc:date.available":["2025-09-09T19:38:15Z"],"dc:date.issued":["2025-07-14"],"dc:description.abstract":["Managed aquifer recharge (MAR) with advanced treated wastewater is a promising strategy to combat aquifer depletion; however, its impact on native microbial communities remains insufficiently characterized. Concerns include the potential introduction of pathogens, antibiotic resistance genes (ARGs), and trace organic pollutants, as well as the disruption of native microbial processes critical for contaminant degradation in groundwater. However, it is very challenging to sample aquifer microbes in situ, especially in a representative, time-resolved fashion. With this goal, we developed a passive sampler that employs removable cartridges containing solid media designed to re-create the aquifer environment in a controlled fashion and support consistent, repeatable, time-series sampling. A bench-scale, continuous-loop study compared microbial community dynamics across three candidate porous media: native aquifer sediment, zirconia beads, and laboratory-grade silica sand. 16S rRNA gene amplicon sequencing was applied to profile microbial communities and revealed that native aquifer sediment from the aquifer of study best reflected influent microbial composition and temporal shifts, particularly among the dominant bacterial phyla Proteobacteria, Bacteroidota, Planctomycetota, and Verrucomicrobiota. Native sediment also exhibited more spatial consistency in microbial diversity. Based on these findings, a full-scale, 3Dprinted sampler using native sediment was developed for long-term monitoring in MAR systems to support future study of the impacts of introduction of advanced treated water into an aquifer."],"dc:description.abstractgeneral":["Though more of the earth is covered in water in comparison to land, only a small portion of this water is drinkable and can sustain human life. It is important to acknowledge that water operates in a “circle of life”, whereas no water is new water. Every drop of water we use to drink or even flush our toilets has been cycled through every phase of life. Therefore, it is imperative that we preserve the drinking water resources that we have, as we embrace the challenges of providing sustainable freshwater resources in the face of climate change and increased water demand. One way that we are able to do this is through managed aquifer recharge (MAR) into groundwater, which is a vital source of drinking water that is under severe pressure across the United States. Groundwater provides nearly half of the domestic water use in the U.S, including both private and public well supplies. MAR technologies work to address the growing water concerns by taking highly treated wastewater and pumping it into groundwater systems, which allows us to store water for later consumption. MAR helps prevent problems like land subsidence and supports long-term use of water for drinking, farming, and other needs. However, there are still important questions about how this practice affects subsurface ecosystems, particularly the microbial communities that naturally exist in groundwater. The use of this technology has been popularized around the world and within the U.S. there are 36 states as of 2020 using MAR. With the growing usage, there is an important to have a comprehensive understanding of the effects of using MAR for both human and environmental health today and in the future. Such effects could be on both “bad” microbes, which cause disease, and “good” microbes, which can help to biodegrade pollutants in the environment. MAR could accidentally introduce pathogens or antibiotic resistance genes (ARGs) into these systems, while on the other hand, enhancing the diversity of microbes capable of further breaking down any residual pollutants in the MAR water. To study these effects, scientists need ways to collect microbial samples over time without disturbing the aquifer environment. To address this, we developed a passive sampler that mimics natural aquifer conditions and allows for periodic collection of microbes. In a controlled lab experiment, we tested three materials inside the sampler: native aquifer sediment, zirconia beads, and sand to see which best captured changes in microbial communities over time. Using DNA sequencing, we found that the sediment was the most effective. It captured a more stable and representative picture of the microbial community, especially over time, and showed similarities to the microbes present in the surrounding water. Based on these findings, we created a full-scale version of the passive sampler using 3D printing and sediment as the core material. This tool can now be used in MAR systems to monitor microbial changes. Understanding these changes is essential for ensuring that MAR is not only effective but also safe for the environment and public health."],"dc:description.degree":["Master of Science"],"dc:format.medium":["ETD"],"dc:format.mimetype":["application/pdf"],"dc:identifier.uri":["https://hdl.handle.net/10919/137702"],"dc:publisher":["Virginia Tech"],"dc:rights":["In Copyright"],"dc:rights.uri":["http://rightsstatements.org/vocab/InC/1.0/"],"dc:subject":["Managed aquifer recharge","soil aquifer treatment","passive sampler","microbial dynamics monitoring","water reclamation/reuse"],"dc:title":["Assessment of a Passive Sampler for Aquifer Microbial Community Profiling and Comparison of Porous Media"],"dc:type":["Thesis"],"dc:type.dcmitype":["Text"],"thesis:degree_discipline":["Civil Engineering"],"thesis:degree_level":["masters"],"thesis:degree_name":["Master of Science"],"thesis:institution_name":["Virginia Polytechnic Institute and State University"]},"updated_at":"2026-07-22T22:19:41Z"}