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- All Subjects: Environmental engineering
- Creators: Arizona State University
- Status: Published
Description
Wastewater-based epidemiology (WBE) has emerged as a powerful tool for community health assessment, using wastewater-borne biological and chemical markers as analytical targets. This study investigates the critical influence of sampling frequency on the resultant estimates of opioid consumption and the prevalence of SARS-CoV-2 infections at the neighborhood level using common WBE biomarkers including fentanyl, norfentanyl, and the SARS-CoV-2 N1 gene as targets. The goal was to assess sampling methodologies that include the impact of the day of the week and of the sampling frequency. Wastewater samples were collected two or three times per week over the course of five months (n=525) and analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) or reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) for target chemical or molecular indicators of interest. Results showed no statistically significant differences for days of the week (i.e., Tuesday vs. Thursday vs. Saturday) for 24-hour composite samples analyzed for fentanyl or SARS-CoV-2; however, concentrations of the human metabolite of fentanyl, norfentanyl, were statistically different between Tuesday and Saturday (p < 0.05). When data were aggregated either by Tuesday/Thursday or Tuesday/Thursday/Saturday to examine sensitivity to sampling frequency, data were not statistically different except for the Tuesday/Thursday weekly average and Saturday for norfentanyl (p < 0.05). These results highlight how sample collection and data handling methodologies can impact wastewater-derived public health assessments. Care should be taken when selecting an approach to the sampling frequency based on the public health concerns under investigation.
ContributorsAJDINI, ARIANNA (Author) / Halden, Rolf (Thesis advisor) / Driver, Erin (Committee member) / Conroy-Ben, Otakuye (Committee member) / Arizona State University (Publisher)
Created2023
Description
Mining-influenced water (MIW) is an acidic stream containing a typically acidic pH (e.g., 2.5), sulfate, and dissolved metal(loid)s. MIW has the potential to affect freshwater ecosystems and thus MIW requires strategies put in place for containment and treatment. Lignocellulosic sulfate-reducing biochemical reactors (SRBRs) are considered a cost-effective passive treatment for MIW and have been documented to continuously treat MIW at the field-scale. However, long-term operation (> 1 year) and reliable MIW treatment by SRBRs at mining sites is challenged by the decline in sulfate-reduction, the key treatment mechanism for metal(loid) immobilization. This dissertation addresses operational designs and materials suited to promote sulfate reduction in lignocellulosic SRBRs treating MIW. In this dissertation I demonstrated that lignocellulosic SRBRs containing spent brewing grains and/or sugarcane bagasse can be acclimated in continuous mode at hydraulic retention times (HRTs) of 7-12 d while simultaneously removing 80 ± 20% – 91 ± 3% sulfate and > 98% metal(loid)s. Additionally, I showed that decreasing the HRT to 3 d further yields high metal(loid) removal (97.5 ± 1.3% – 98.8 ± 0.9%). Next, I verified the utility of basic oxygen furnace slag to increase MIW pH in a two-stage treatment involving a slag stage and an SRBR stage containing spent brewing grains or sugarcane bagasse. The slag reactor from the two-stage treatment increased MIW pH from 2.6 ± 0.2 to 12 ± 0.3 requiring its re-combination with fresh MIW to reduce pH to 5.0 ± 1.0 prior to entering the lignocellulosic SRBRs. The lignocellulosic SRBRs from the two-stage treatment successfully continued to remove metal(loid)s, most notably cadmium, copper, and zinc at ≥ 96%. In additions to these outcomes, I performed a metadata analysis of 27 SRBRs employing brewers spent grains, sugarcane bagasse, rice husks and rice bran, or a mixture of walnut shells, woodchips, and alfalfa. I found that sugarcane bagasse SRBRs can remove between 94 and 168 mg metal(loid) kg–1 lignocellulose d–1. In addition, Bacteroidia relative abundances showed a positive correlation with increasing sulfate removal across all 27 SRBRs and are likely essential for the degradation of lignocellulose providing electron donors for sulfate reduction. Clostridia and Gammaproteobacteria were negatively correlated with sulfate reduction in the 27 SRBRs, however SRBRs that received alkalinized MIW had lower relative abundances of Clostridia, Gammaproteobacteria, and methanogenic archaea (known competitors for sulfate-reducing bacteria). Overall, my dissertation provides insight into lignocellulosic materials and operational designs to promote long-term sulfate-reduction in lignocellulosic SRBRs treating MIW.
ContributorsMiranda, Evelyn Monica (Author) / Delgado, Anca G (Thesis advisor) / Santisteban, Leonard (Committee member) / Hamdan, Nasser (Committee member) / Rittmann, Bruce (Committee member) / Arizona State University (Publisher)
Created2023
Description
This dissertation encompasses the interaction of antimicrobial chemicals and emerging contaminants with multi-drug resistant (MDR) bacteria and their implications in engineered systems. The aim is to investigate the effect of combination antimicrobials on MDR bacteria E. coli, evaluate the extent of synergism and antagonism of utilizing two distinct biocidal chemicals, and evaluate the influence of endocrine-disrupting chemicals (EDCs) on protein production in response to stressors. Resistance mechanisms of bacteria such as E. coli include the use of protein systems that efflux excess nutrients or toxic compounds. These efflux proteins activate in response to environmental stressors such as contaminants and antimicrobials to varying degrees and are major contributors to antibiotic resistance in pathogenic bacteria. As is the case with engineered microbial environments, large quantities of emerging contaminants interact with bacteria, influencing antibiotic resistance and attenuation of these chemicals to an unknown degree. Interactions of antimicrobials on MDR bacteria such as E. coli have been extensively studied for pathogens, including synergistic combinations. Despite these studies in this field, a fundamental understanding of how chemicals influence antibiotic resistance in biological processes typical of engineered microbial environments is still ongoing. The impacts of EDCs on antibiotic resistance in E. coli were investigated by the characterization of synergism for antimicrobial therapies and the extrapolation of these metrics to the cycling of EDCs in engineered systems to observe the extent of antibiotic resistance proteins to the EDCs. The impact of this work provides insight into the delicate biochemistry and ongoing resistance phenomena regarding engineered systems.
ContributorsNovoa, Diego Erick (Author) / Conroy-Ben, Otakuye (Thesis advisor) / Abbazadegan, Morteza (Committee member) / Krajmalnik-Brown, Rosa (Committee member) / Arizona State University (Publisher)
Created2022
Description
The measurement of the radiation and convection that the human body experiences are important for ensuring safety in extreme heat conditions. The radiation from the surroundings on the human body is most often measured using globe or cylindrical radiometers. The large errors stemming from differences in internal and exterior temperatures and indirect estimation of convection can be resolved by simultaneously using three cylindrical radiometers (1 cm diameter, 9 cm height) with varying surface properties and internal heating. With three surface balances, the three unknowns (heat transfer coefficient, shortwave, and longwave radiation) can be solved for directly. As compared to integral radiation measurement technique, however, the bottom mounting using a wooden-dowel of the three-cylinder radiometers resulted in underestimated the total absorbed radiation. This first part of this thesis focuses on reducing the size of the three-cylinder radiometers and an alternative mounting that resolves the prior issues. In particular, the heat transfer coefficient in laminar wind tunnel with wind speed of 0.25 to 5 m/s is measured for six polished, heated cylinders with diameter of 1 cm and height of 1.5 to 9 cm mounted using a wooden dowel. For cylinders with height of 6 cm and above, the heat transfer coefficients are independent of the height and agree with the Hilpert correlation for infinitely long cylinder. Subsequently, a side-mounting for heated 6 cm tall cylinder with top and bottom metallic caps is developed and tested within the wind tunnel. The heat transfer coefficient is shown to be independent of the flow-side mounting and in agreement with the Hilpert correlation.
The second part of this thesis explores feasibility of employing the three-cylinder concept to measuring all air-flow parameters relevant to human convection including mean wind speed, turbulence intensity and length scale. Heated cylinders with same surface properties but varying diameters are fabricated. Uniformity of their exterior temperature, which is fundamental to the three-cylinder anemometer concept, is tested during operation using infrared camera. To provide a lab-based method to measure convection from the cylinders in turbulent flow, several designs of turbulence-generating fractal grids are laser-cut and introduced into the wind tunnel.
ContributorsGupta, Mahima (Author) / Rykaczewski, Konrad (Thesis advisor) / Pathikonda, Gokul (Thesis advisor) / Middel, Ariane (Committee member) / Arizona State University (Publisher)
Created2024