Name: Rayelle Gusmão Tessarollo
Type: MSc dissertation
Publication date: 29/03/2018
Advisor:
Name |
Role |
|---|---|
| Julio Tomás Aquije Chacaltana | Advisor * |
Examining board:
| Name |
Role |
|---|---|
| Gilberto Fonseca Barroso | External Examiner * |
| José Antônio Tosta dos Reis | Internal Examiner * |
| Julio Tomás Aquije Chacaltana | Advisor * |
Summary: Increasing microbial contamination of estuarine and coastal waters is an important issue in water quality management because of its implications for public health. The municipality of Vitória, capital of the state of Espírito Santo, is one of the Brazilian cities that suffer from the pollution problems of coastal waters. This work evaluated the contamination of the waters of the Vitória Island Estuarine System by domestic sewage, from the implementation of a numerical model, to analyze the distribution and concentration of the thermotolerant coliforms bacteria in this system and its relationship with the hydrodynamic forcing, under the principles of computational fluid mechanics. In the modeling, the behavior of thermotolerant coliforms was simulated considering or not the decay process. The two approaches were applied in two distinct scenarios. The first scenario considered only the measured values of thermotolerant coliforms from the five tributaries (Santa Maria da Vitória river, Bubu river, Itanguá river, Aribiri river and Marinho river). The second scenario considered the values of thermotolerant coliforms measured in the five tributaries and also the estimated values of urban point sources that in the Vitória Bay and Canal da Passagem. In addition, using the Lagrangian virtual derivers launched at the mouth of the Santa Maria da Vitória river, the residence time for the different tracer groups was obtained, crossing the mouth of the Bay of Vitória and the Canal da Passagem. The water quality model was validated and the value obtained for the concordance index was 0.92, indicating a satisfactory agreement between the results of the model and the data of the samplings and the average absolute percentage error was 27.12%. The results of the bacterial dispersion allow us to state that the currents confers high effluent dilution and dispersion capacity in the study area. The highest bacterial concentrations are close to the sources and although the processes involved in the decay of the bacteria decrease their concentrations along the estuary, the thermotolerant coliforms plume reaches the beaches by advection. The tracers launched in the south arm and in the north arm of the landing of the Santa Maria of the River have an average residence time of approximately 36 days and 38 days to leave the Bay of Vitoria, respectively. The tracers launched on the north arm had a residence time 37.5 days to leave the Passage Channel.
