http://repositorio.ufc.br/handle/riufc/501 2026-04-08T21:36:05Z http://repositorio.ufc.br/handle/riufc/85408 Título: Sistemas hidrológicos em transformação: impactos das mudanças antrópicas na dinâmica hidrológica da bacia hidrográfica do Rio São Francisco, Brasil Autor(es): Lima, Carlos Eduardo Sousa Abstract: In the Anthropocene, the increasing human influence on the hydrological cycle of watersheds has made their water availability and response patterns to climate extremes – both wet and dry – depend on both natural and anthropogenic factors. In this context, this thesis evaluated the impact of anthropogenic changes on the hydrological dynamics of watersheds. As a case study, the São Francisco River Watershed (BHSF) and the Grande River Basin (GRB), an important sub-basin of the BHSF, were used. Three different approaches were employed for this proposed assessment: the first applied more generally to the BHSF, while the second and third were applied more specifically to the GRB. In the first approach, the concept of climate elasticity of streamflow was applied to 10 sub-basins of the BHSF, enabling an evaluation of streamflow sensitivity to climate variations and the decomposition of total streamflow variation into climatic and anthropogenic components. In the second, a new methodology for assessing the impact of human activities on the development of hydrological droughts was proposed: the Drought Roulette Analysis (DRA). In the third, the watershed was interpreted as a complex hydrological system with multiple equilibrium states that switch between them in response to climatic and anthropogenic forcing. The results from these approaches led to the conclusion that anthropogenic activities have decreased water availability, increased the sensitivity of streamflow to climate variations, and slowed hydrological recovery after drought events, with streamflow deviations persisting even after precipitation levels are restored. Equally important, the results from the third approach showed that a watershed can naturally exhibit a non- stationary hydrological regime characterized by multiple hydrological states and a variable rainfall-runoff relationship; anthropogenic activities, in turn, modulate this non-stationarity, accentuating the asymmetry in transitions between these states. Additionally, incorporating information on hydrological states significantly improved the hydrological modeling process, providing a more dynamic representation of the variable rainfall-runoff relationship. Overall, these findings point to a dynamic risk to water availability and hydrological extremes in the BHSF, and more specifically in the Grande River watershed. This dynamic risk arises from the non-stationarity of the hydrological regime, which, although it can be caused by natural factors (climate variability), is strongly linked to human interventions induced in these watersheds. These interventions, in addition to potentially generating non-stationarity, modify transitions between hydrological states and the patterns of drought evolution. The aforementioned dynamic risk introduces significant uncertainty into the water resource management and planning process when not properly considered. The capacity of anthropogenic activities to modulate the non-stationarity of the hydrological regime, as well as the observed hydrological impacts of these activities, underscores the need for integrated management that considers both natural and human factors, along with their interactions and compensatory effects. Tipo: Tese 2026-01-01T00:00:00Z http://repositorio.ufc.br/handle/riufc/85371 Título: Avaliação da produção de biometano em biodigestores com sobras e restos de alimentos por meio de recirculação e inoculação de consórcio microbiológico Autor(es): Souza, Debora Nery de Abstract: The increasing energy demand, the growing volume of waste, the challenges in its proper management, and consequently its inadequate final disposal have necessitated the search for sustainable solutions. Accordingly, this study aimed to evaluate the generation of biogas and biomethane produced through anaerobic digestion of food waste in reactors with different recirculation configurations, varying organic loads, and utilizing a hydrolytic microbial consortium. In an initial phase, two 1.3 m3 reactors were operated semi-continuously: reactor 01 with recirculation at four bottom points and reactor 02 with a single bottom point. Subsequent phases assessed the effect of varying organic load (1% and 5% volatile solids – VS) and bioaugmentation with a hydrolytic microbial consortium (Bacillus subtilis [KJ870046.1] and Alcaligenes faecalis [CP013119.1]). Subsequently, the potential use of the digestate as biofertilizer was evaluated. Various physicochemical parameters were monitored over 90 days. Reactor 01 demonstrated higher efficiency in organic matter degradation, with lower solid concentrations and 60% volatile solids (VS) removal, compared to 8% in reactor 02, in addition to producing more biogas (35.80 Nm3) and biomethane (67.17%) than reactor 02 (26.73 Nm3 biogas and 64.57% biomethane). In the subsequent phases, the microbiological reactor with 1% VS (RM1) and the control reactor with 5% VS (RC5) showed higher efficiency in organic matter degradation with 71% VS removal, compared to 50% for RC1 and 49% for RM5. However, the microbiological reactors produced higher accumulated biogas volumes (22.74 Nm3 for RM5 and 21.22 Nm3 for RM1) relative to the control reactors (17.33 Nm3 for RC5 and 13.37 Nm3 for RC1). In evaluating the potential use of digestates as biofertilizers, the biodigesters with four-point bottom recirculation (R1 and RM1) exhibited greater stabilization than the digestate from the biodigester with single-point bottom recirculation (R2), displaying lower C/N ratios (0.79 and 1.25 for R1 and RM1, respectively, versus 1.63 for R2) and lower sodium concentrations (0.26 and 0.21 g/Kg for R1 and RM1, respectively, versus 0.30 g/Kg for R2). All evaluated digestates presented micronutrient concentrations below the maximum limits established for biofertilizers and macronutrient values below the reference values stipulated by Brazilian and European legislation. It is concluded that four-point bottom pumping recirculation proved more efficient than single- point recirculation, that the bioaugmentation strategy with the hydrolytic microbial consortium was effective for both biogas and biomethane production and organic matter degradation in the biodigesters, and that, generally, all digestates showed potential for use as complementary mineral fertilizer, contributing to the system's circular economy and aiding in environmental sustainability. Tipo: Tese 2025-01-01T00:00:00Z http://repositorio.ufc.br/handle/riufc/84809 Título: Otimização do traçado de redes coletoras de esgoto utilizando estratégias de caminhos mínimos em árvores de busca em largura Autor(es): Farias, Guilherme Marques Abstract: The layout of sewer collection networks is one of the most challenging phases in the planning of sanitation systems, with a significant influence on implementation costs and the hydraulic performance of the network. In urban areas with irregular terrain and high population density, conventional methods, based on the manual interpretation of contour lines and the designer's experience, tend to result in suboptimal solutions, culminating in inverted sections, overloading of manholes, and the need for deep excavations. These limitations reinforce the importance of automated approaches capable of integrating topographic and hydraulic criteria in the layout definition process. Given this scenario, this work proposes the development of an algorithm for the automatic generation of sewer collection network layouts, using shortest path strategies applied to breadth-first search trees. The methodology considers aspects related to Graph Theory, with nodes representing manholes and edges corresponding to pipe sections, and applies routines to identify and correct terminal nodes and nodes with multiple outlets. Criteria such as relative slope, accumulated length, and penalties for sections running against the gravitational flow were used to select hydraulically more favorable and economically viable trajectories. The model was validated in three real-world case studies: the Alto da Expectativa and Belchior neighborhoods in the municipality of Sobral, Ceará, and a large-scale network in Villa Hermosa, Dominican Republic. The results demonstrated the algorithm's effectiveness in reducing the number of inverted sections and reorganizing sub-basins to balance contributing areas, even in scenarios with 3.157 sections, 2.206 nodes, and 219 terminal nodes, as in the case of the Villa Hermosa network. Furthermore, economic efficiency was observed in the Belchior neighborhood case study, where the optimized layout resulted in cost reductions for piping and excavation of approximately R$ 90.302,74. Computational time ranged from three seconds in smaller networks to four minutes for the Villa Hermosa network. The proposed algorithm stood out for its ability to explore all possible paths in the graph, select the most efficient route, and offer a robust and applicable solution for urban planning in the area of basic sanitation projects. Tipo: Tese 2026-01-01T00:00:00Z http://repositorio.ufc.br/handle/riufc/84168 Título: Calibração automática do coeficiente de Manning em redes de drenagem urbana por inteligência computacional com análise de equifinalidade Autor(es): Araujo, Rafael Brito Aguiar de Abstract: Urban stormwater management is a challenge intensified by urbanization, requiring the use of hydrological models like SWMM. The precision of these models, however, depends on the calibration of sensitive parameters, notably the Manning coefficient (n). This process is hindered by the scarcity of observed data, the time-consuming nature of manual calibrations, and the equifinality phenomenon, where multiple parameter sets can yield similar results. Literature establishes theoretical foundations but points to the need for hybrid approaches that integrate computational intelligence to overcome these limitations, especially in estimating parameters for unmonitored locations. This thesis aimed to develop a methodology focused on two computational tools to perform the automatic calibration of the Manning coefficient in sub basins and conduits of urban drainage networks. The methodology of Program 1 (sub-basins) applied Genetic Algorithms (GA) to optimize the N-Imperv and N-Perv coefficients, implementing a statistical strategy to filter the best solutions, seeking to mitigate equifinality. The methodology of Program 2 (conduits) used a hybrid approach: it applied the False Position Method for the calibration of sections with observed data and then used these results to train Machine Learning (ML) models, which estimated the coefficients in sections without observed data. The results from Program 1 revealed that calibration based on surface runoff flow data is superior to that based on depth data, allowing for the nearly perfect identification of N-Imperv (errors < 0.2%). However, N-Perv (pervious) proved to be a parameter of difficult identification and high sensitivity, whose calibration is strongly dependent on other model configurations, such as the selected infiltration method. The results from Program 2 confirmed the effectiveness of the hybrid ML approach, whose precision was directly proportional to the monitoring coverage. The research also empirically confirmed equifinality by demonstrating that large errors in Manning parameters can still produce hydraulically acceptable errors in water depth. The work concludes that the combination of physical models, optimization algorithms (GA), and machine learning techniques are viable strategies for automatic calibration, but obtaining high-precision results in drainage networks remains dependent on a significant amount of monitoring data. Tipo: Tese 2025-01-01T00:00:00Z