Navegando por Autor "BARBOSA, Renata Kelly da Costa"

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Avaliação do tratamento de efluentes da indústria de alumina no contexto dos impactos da mineração na Amazônia Oriental
(Universidade Federal do Pará, 2014-06-26) BARBOSA, Renata Kelly da Costa; BERRÊDO, José Francisco; http://lattes.cnpq.br/1338038101910673; FRANÇA, Silvia Cristina Alves; http://lattes.cnpq.br/9463680545957601
The state of Pará has one of the world's largest mineral reserves, and bauxite, the rock from which aluminum is extracted is particularly plentiful here. However, the process for obtaining aluminum produces impactful environmental waste (red mud), a highly caustic residue. The general objective of this study was to characterize the effluent (solid and liquid phases) generated by alumina refining, and to evaluate the efficiency of the DAF ( Dissolved Air Flotation) process in order to improve the quality of this, so that it might be possible to reuse the water. The observed results were as follows: the chromium concentration in Pará River is higher than the legal limit. The riverbed sediment has low bioavailability due to its characteristics of silt and fine sand, and is composed mainly of quartz. The collected phytoplankton and oysters near the refinery showed high levels of aluminum and other chemical elements (Ca, Co, Cu, Mg and S), especially when compared with those from the control point. The red mud is composed of fine particles of chemical composition 50% Fe2O3 and Al2O3. DAF tests showed satisfactory results with solids removal efficiency reaching 99% with T-8 and 99.4% in the E-4f, with final turbidity values less than reached 8.5 NTU. The recycle ratio and the concentration of flocculant were shown to be important variables in the experiments, and showed exhibited better results in the removal efficiency of solids. Acute and chronic ecotoxicological tests showed good results in the efficiency of wastewater treatment by using the DAF. It is expected that this study will contribute to scientific knowledge, and may serve as an alternative for the treatment of effluent from the alumina industry. Moreover, the study reached important results that can help improve the quality of waste water and its reuse in the manufacturing process, which can reduce water consumption and environmental risks.