Ciencias Exactas y Ciencias de la Salud
Permanent URI for this collectionhttps://hdl.handle.net/11285/551039
Pertenecen a esta colección Tesis y Trabajos de grado de las Maestrías correspondientes a las Escuelas de Ingeniería y Ciencias así como a Medicina y Ciencias de la Salud.
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- Characterization of the spatial variations in the structure and diversity of microbial communities within and between the stages of a wastewater treatment plant based on passive methods(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2017-11-24) Verduzco Garibay, Marycarmen; SENES GUERRERO, CAROLINA; 253929; Senés Guerrero, Carolina; tolmquevedo, emipsanchez; Anda Sánchez, José de; Escuela de Ingeniería y Ciencias; Campus Monterrey; Gradilla Hernández, Misael SebastiánWastewater is frequently discharged directly to water bodies without any treatment in developing countries. Despite the efforts to treat a higher percentage of sewage, wastewater treatment plants (WWTP) often end up abandoned due to the high maintenance and operational costs. Consequently, untreated wastewater often reaches water bodies and causes several pollution problems, such as eutrophication, affecting the communities' public health. To achieve the Sustainable Development Goal (SDGs) number six of the United Nations, which seeks to substantially improve water quality by 2030, lowering the release of pollutants and toxins into wastewater and safe reuse and recycling of treated water. It is crucial to switch from centralized to decentralized WWTP systems that require less maintenance and operation costs. Microorganisms are essential in wastewater treatment since they are involved in nutrient and organic matter removal through several metabolic pathways. However, microbial communities are susceptible to environmental variation, design and operational features of WWTP. Moreover, few studies have been performed focusing on the microbial communities within the treatment stages of complete decentralized systems. Therefore, this work's general objective was to characterize the spatial variations of the bacterial communities occurring in a decentralized wastewater treatment plant. This work is composed of three chapters. Chapter one describes the problem statement and context, research question, solution overview, and main contributions. Chapter two describes the types of constructed wetlands (CW) and the pollutant removal processes that occur within them. Additionally, this chapter discusses the effect of environmental parameters as well as operational and design factors on the structure, diversity, and activity of microbial communities. Chapter three presents the characterization of bacterial communities of a decentralized WWTP (the system under analysis) composed of a ST, an UAF, and a HFCW. Microbial characterization was carried out by high-throughput sequencing of 16S rRNA (V3-V4 region) to evaluate the spatial distribution of bacteria communities within a septic tank (ST), an up-flow anaerobic filter (UAF), and a horizontal flow constructed wetland (HFCW). Moreover, the effect of physicochemical parameters on the structure and diversity of bacterial communities was analyzed. Finally, chapter four describes future perspectives of this work and the importance of investigating the mechanisms to remove pathogenic microorganisms in the CW and the influence of iron in microbial communities' behavior during wastewater treatment.
- Mathematical Modelling of a Domestic Wastewater Treatment System Combining a Septic Tank, an Up flow Anaerobic Filter, and a Constructed Wetland(Instituto Tecnológico y de Estudios Superiores de Monterrey) Fernández del Castillo Barrón, Alberto; SENES GUERRERO, CAROLINA; 253929; Senés Guerrero, Carolina; puelquio, emipsanchez; De Anda Sánchez, José; Díaz Torres, Osiris; Escuela de Ingeniería y Ciencias; Campus Monterrey; Gradilla Hernández, Misael SebastiánWastewater treatment is essential for environmental protection, public health, and to ensure water supply for future generations. Conventional treatment technologies, such as activated sludge, are energy-intensive and require constant maintenance as they were designed for large cities. These technologies are not suitable for wastewater treatment in small communities and rural areas. Decentralized treatment approaches combining Anaerobic Reactors (AR) and Constructed Wetlands (CW) have proven more appropriate in these cases. These passive treatment methods require low investment and maintenance. Additionally, they allow for onsite water reuse and energy generation. The combined configuration of an AR sequentially coupled with a CW have proven to be an efficient system by which the limitations of the individual units (AR and CW) are overcome. Chapter one provides the motivation related to global needs of wastewater treatment, problem statement and context, which is the deficit of treatment and current technologies deficiencies. The research question and solution overview provided by the mathematical modeling applied to decentralized treatment technologies. Finally, the main contributions of this work to the state of the art are detailed. In Chapter 2, several systems combining three types of AR (Up-flow Anaerobic Sludge Blanket, Anaerobic Baffled Reactor, and Up-flow Anaerobic Filter) with CW are reviewed as well as their capabilities and drawbacks. An emphasis was made to analyze their performances, characteristics, and the processes involved in pollutant removal (solids, organic matter, nutrients, and sulfate). In Chapter 3, the experimental work of this thesis is presented. Mathematical modeling of the pollutant removal processes occurring in wastewater treatment plants can provide detailed and valuable information. More profound knowledge provided by these models is useful for predicting the future behavior of the treatment systems and can be applied to optimize the operation and facilitate monitoring. Optimal operation procedures and feasible monitoring are essential to ensure the successful implementation of these technologies in rural areas and small communities where investment budgets are limited. The system's efficiency and robustness can also be increased by applying mathematical modeling in design and control. The experimental system evaluated consisted of a Septic Tank (ST), an Up-flow Anaerobic Filter, and a Horizontal Flow Constructed Wetland (HFCW). Sampling was done biweekly for three months. BOD5, COD, TSS, TKN, ON, NH4+, NO2- and NO3- levels were measured. The experimental data was used to develop three different mathematical models: First order kinetics models, Linear Multiple Regression models, and Mass balance models. The first-order kinetic models developed were efficient to predict pollutant removal with significant precision. Multiple linear regression models were found to help reduce the cost and time of monitoring procedures. These models also reflected physical, chemical, and biological processes involved in pollutant removal in a logical manner. Finally, mass balance models indicated that the system is highly tolerant to influent wastewater variations.
- Differential Transcriptome and Lipidome Analysis of the Microalga Desmodesmus abundans Under a Continuous Flow of Model Cement Flue Gas in a Photobioreactor(Instituto Tecnológico y de Estudios Superiores de Monterrey) Mora Godínez, Shirley María; Pacheco Moscoa, Adriana; Senés Guerrero, CarolinaMicroalgae represent a potential strategy for flue gas mitigation as they capture CO2 at high rates. Flue gases can also supply certain nutrients and, as a result, it can be valorized through biomass conversion into value-added compounds. The objective of this study was to characterize growth and analyze transcriptome, lipidome and cellular structure and composition of Desmodesmus abundans under continuous flow of cement model flue gas (MFG) in a 1 L photobioreactor using two strains adapted for nine years to atmospheres of 50% CO2 and air, referred to as HCA (high CO2 acclimated) and LCA (low CO2 acclimated), respectively. Controls with the LCA strain were also evaluated in air, CO2 and CO2+cement kiln dust (CKD). Higher initial growth rates were observed with strain HCA; however, at the end of the run (5 days) similar biomass productivity was reached by the two strains (0.30-0.34 g d.w. L-1 d-1). As expected, the CO2 control presented the highest growth rate (1.7-fold higher than under MFG), and when CKD was incorporated a slightly decreased (14 %) in growth was observed. Transcriptome analysis by RNA-seq, performed at day 4, resulted in a de novo assembly of 70 458 contigs with a N50 of 1 677 bp. Strain comparison under MFG resulted in 16 435 up-regulated and 4 219 down-regulated genes for strain HCA. Most of these genes were related with nucleotide, amino acid and carbon metabolisms; specifically, C3 and C4 cycle, glycolysis and gluconeogenesis, and TCA cycle, where almost all the contigs were up-regulated. In accordance, cell component GO terms up-regulated were in cell wall, chloroplast and photosystems. Likewise, starch and TAG metabolism were up-regulated. Cell structure analysis by SEM and TEM showed that most cells of both strains under MFG were unicellular contrary to typical Desmodesmus morphology; under air, some cells still preserved a grouping morphology. Strains cell size under MFG was similar (17-37 μm2), while under air cells were significant smaller (7-13 μm2). Both strains under MFG possessed high content of starch granules, a disorganized chloroplast and several lipid bodies, while a thicker cell wall was only observed in strain HCA. Biomass composition at the end of the run (day 5) showed no differences in proximate analysis between strains under MFG. A 1.8 to 2-fold higher protein content in strain LCA was found in complete medium (BG-11) than under MFG (BG-11-N-S). Under MFG, LCA presented the highest starch content (47.2 ± 22.3 % d.w) followed by HCA (23.1 ± 4.5 % d.w). On the contrary, HCA showed a higher content of pigments compared to LCA but the highest values were found in the control with only CO2. Lipidome analysis resulted in 663 detected features. Under MFG no many differences were found between strains by day 5; however, clear differences were observed at day 4 when both strains were in exponential growth. Particularly, 12 glycerolipids (GL) and 18 glycerophospholipids (GP) increased, and 27 GL and 3 GP decreased in HCA compared LCA. Still, most differences were found when strain LCA under MFG was compared with CO2+CKD (incomplete vs complete culture medium) that showed changes in GL (42 increased and 27 decreased) and GP (58 increased and 42 decreased), possibly attributed to low N in MFG. The results presented in this study show significant differences between strains HCA and LCA under MFG. However, most differences were observed at the transcriptome level (day 4), while biomass production was comparable at the end of the experimental period (day 5). Morphological changes appeared to be induced by the high CO2 condition at the moment of growth, with no significant differences between acclimated strains, except for a thicker cell wall in the HCA strain. Overall, both strains presented a high content of starch that represents a high value compound under MFG. Further studies could contemplate continuous cultures under MFG with longer experimental periods (>5 days) to validate differences between strains. Also, explore differences between strains at the genome level such as synonymous mutation rates by sequencing and studies of epigenetic changes. Additionally, metabolome and proteome analysis to better understand differences under the different control conditions.