Browsing by Author "Stadler, Lauren"
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Item Evaluating the Swelling/Degradation Behavior of Calcium Alginate Beads in Synthetic Wastewater Under Varied Environmental Conditions(2024-04-17) Cadena Semanate, Eliana Salome; Getachew, Bezawit; Stadler, Lauren; Verduzco, RafaelBacteria encapsulation has gained attention as a promising technique to enhance the biodegradation of contaminants in wastewater. While encapsulation offers substantial benefits, including enhanced biological stability, higher biomass concentration, enhanced symbiotic relationships, and partition advantages, 1 it also presents challenges such as mass transfer limitations and matrix instability. This research seeks to gain insight into the behavior of calcium alginate beads under conditions simulating real-world wastewater environments. Dynamic weight change of beads was measured over time considering varying crosslinking degrees of CaCl2 (0.1M, 0.3M, 0.5M), different wastewater strengths (NaCl concentrations of 0 g/L, 15g/L, and 35g/L), and high turbulence (shaking at 200rpm). Results suggest that higher crosslinker concentrations yield smaller beads, but this does not significantly alter the maximum water uptake in synthetic wastewater. Moreover, beads show varying swelling and degradation rates depending on the medium’s ionic composition, especially in the presence of Na+ ions. Water uptake increased, and bead stability decreased with high NaCl concentrations. Similarly, high turbulence conditions increased the water uptake ratio. Overall, all of the beads resisted degradation and didn’t dissolve completely for at least 78 days. The study suggests a crosslinker concentration of 0.3M or higher is promising for optimal stability in wastewater applications. This research provides insights into the chemical and physical factors that affect the stability of calcium alginate beads in synthetic wastewater. However, further research is required to develop more effective matrixes for bacteria encapsulation for wastewater applications.Item Mesoscale Modeling of Distributed Water Systems Enables Policy Search(Wiley, 2023) Zhou, Xiangnan; Duenas-Osorio, Leonardo; Doss-Gollin, James; Liu, Lu; Stadler, Lauren; Li, Qilin; Nanosystems Engineering Research Center for Nanotechnology-Enabled Water TreatmentIt is widely acknowledged that distributed water systems (DWSs), which integrate distributed water supply and treatment with existing centralized infrastructure, can mitigate challenges to water security from extreme events, climate change, and aged infrastructure. However, it is unclear which are beneficial DWS configurations, i.e., where and at what scale to implement distributed water supply. We develop a mesoscale representation model that approximates DWSs with reduced backbone networks to enable efficient system emulation while preserving key physical realism. Moreover, system emulation allows us to build a multiobjective optimization model for computational policy search that addresses energy utilization and economic impacts. We demonstrate our models on a hypothetical DWS with distributed direct potable reuse (DPR) based on the City of Houston's water and wastewater infrastructure. The backbone DWS with greater than 92% link and node reductions achieves satisfactory approximation of global flows and water pressures, to enable configuration optimization analysis. Results from the optimization model reveal case-specific as well as general opportunities, constraints, and their interactions for DPR allocation. Implementing DPR can be beneficial in areas with high energy intensities of water distribution, considerable local water demands, and commensurate wastewater reuse capacities. The mesoscale modeling approach and the multiobjective optimization model developed in this study can serve as practical decision-support tools for stakeholders to search for alternative DWS options in urban settings.Item Public Health Interventions Guided by Houston’s Wastewater Surveillance Program During the COVID-19 Pandemic(Sage, 2023) Hopkins, Loren; Ensor, Katherine B.; Stadler, Lauren; Johnson, Catherine D.; Schneider, Rebecca; Domakonda, Kaavya; McCarthy, James J.; Septimus, Edward J.; Persse, David; Williams, Stephen L.Since the start of the COVID-19 pandemic, wastewater surveillance has emerged as a powerful tool used by public health authorities to track SARS-CoV-2 infections in communities. In May 2020, the Houston Health Department began working with a coalition of municipal and academic partners to develop a wastewater monitoring and reporting system for the city of Houston, Texas. Data collected from the system are integrated with other COVID-19 surveillance data and communicated through different channels to local authorities and the general public. This information is used to shape policies and inform actions to mitigate and prevent the spread of COVID-19 at municipal, institutional, and individual levels. Based on the success of this monitoring and reporting system to drive public health protection efforts, the wastewater surveillance program is likely to become a standard part of the public health toolkit for responding to infectious diseases and, potentially, other disease-causing outbreaks.Item Surface Imprinted Particles for the Removal of Coronaviruses from Aqueous Solution(2023-01-30) Senehi, Naomi; Alvarez, Pedro; Stadler, LaurenCoronaviruses are responsible for the deadly COVID-19 pandemic and are the second most common cause of the common cold. Efforts to monitor coronaviruses in wastewater treatment systems have skyrocketed, however, current analytical methods to quantify coronavirus virions require a combination of selective assays (e.g., RT-qPCR) and infectious assays (e.g., TCID50). When combined with devices such as sensors, molecular imprinting is a promising strategy to obtain a direct measure of specific infectious viruses. However, effective imprinting templates are yet to be elucidated. We designed and fabricated glycoprotein imprinted particles (GIPs). GIPs were found to selectively remove two types of coronaviruses (HCoV-OC43 and HCoV-NL63) efficiently from solution with greater than 1-log (90%) removal in under ten minutes. Selective adsorption was maximized at pH 6, the glycoprotein isoelectric point, which highlights the role of electrostatic interactions on separation efficiency and was confirmed using protein modeling. At pH 6, during competitive adsorption, the GIPs adsorbed more of the target virions (HCoV-OC43) than non-target virions (HCoV-NL63) which further promotes the use of glycoprotein templates for effective imprinted particles. Overall, these results highlight the benefits of GIPs and pave the way for imprinting techniques for the separation of other viruses.