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Abstract(s)
Os efluentes industriais diversas vezes são descarregados de forma descontrolada, sem o nível de tratamento adequado e contendo compostos refratários e tóxicos, revelando-se os processos oxidativos avançados uma opção interessante. Tais processos além de alta eficiência e elevada taxa de degradação, possuem baixo custo e se adequam às preocupações ambientais, o que torna viável a sua utilização. Dentre estes processos, destaca-se o Processo de Fenton que utiliza ferro (II) como catalisador e peróxido de hidrogénio como agente oxidante, formando grupos hidroxilo altamente reativos aos compostos indesejáveis no meio.
O presente trabalho teve por objetivo a otimização do processo de tratamento do lixiviado e do concentrado da osmose inversa dum Aterro Sanitário, pelo processo de Fenton, tendo sido introduzida como inovação a utilização de um reator de leito fluidizado. A eficiência do processo foi avaliada mediante parâmetros determinantes, tais como a Carência Química de Oxigénio, Sólidos Sedimentáveis e volume de lama formada. Para o lixiviado do aterro e o concentrado da unidade de osmose inversa foram obtidos valores da CQO de 12000 mg O2.L-1 e 25000 mg O2.L-1, respetivamente, o que indica claramente a necessidade e complexidade do tratamento a implementar.
Os ensaios Fenton foram realizados em batch, otimizando a razão Fe+2:H202. Para os dois efluentes a razão escolhida para prosseguir os ensaios foi 1:10 por demonstrar valores satisfatórios quer para remoção de CQO (Lixiviado – 57%; Concentrado – 63%), quer no volume de lama gerada (Lixiviado – 260 mL.L-1; Concentrado – 410 mL.L-1). Relativamente à % de remoção de CQO, destacou-se o ensaio na presença de leito de carvão ativado (Lixiviado - 68%; Concentrado - 82%), não diferindo significativamente a percentagem de lama formada.
O processo de tratamento prévio por coagulação/floculação, mostrou-se um possível aliado no aumento de remoção de CQO: 90% e 83% para o lixiviado e concentrado, respectivamente. Contudo, pouco favorável foi o volume de lama gerado no processo (Lixiviado – 910 mL.L-1; Concentrado – 870 mL.L-1). Foi comprovado que a reação de Fenton em reator de leito fluidizado, enchimento de carvão – 40% de volume, permite uma eficiência elevada de remoção de CQO.
Industrial effluents are often discharged of in an uncontrolled manner, without the proper treatment and include refractory and toxic compounds, with advanced oxidative processes proving to be an interesting option. These processes, in addition to high economic efficiency and high degradation rates, have low cost and are suitable according to environmental concerns, what makes viable their use. Among these processes, they include the Fenton Process that uses iron (II) as a catalyst and hydrogen peroxide as an oxidizing agent, forming hydroxyl groups that are highly reactive to undesirable compounds in the medium. The present work aimed to optimize the inverse osmosis treatment process at the landfill with the aid of the Fenton process, having been introduced as an innovation the use of fluidized bed reactor. An efficiency analysis was performed using determinant parameters, such as Chemical Oxygen Demand, Sedimentable Solids and volume of sludge formed. For soil leachate and crude concentrate from the reverse osmosis unit, COD values 12000 mg O2.L-1 and 25000 mg O2.L-1, respectively, are indicated which clearly indicates the need and use of the treatment to be implemented. The Fenton tests were performed in batch, optimizing the Fe+2:H202 ratio. For the two effluents, the ratio chosen to continue the tests was 1:10 for demonstrating satisfactory values both for COD removal (Leachate - 57%; Concentrate - 63%), and in the volume of sludge generated (Leachate - 260 mL.L-1; Concentrate - 410 mL.L-1). Regarding the% of COD removal, the test stood out in the presence of activated carbon bed (Leachate - 68%; Concentrate - 82%), not significantly differing in the percentage of sludge formed. The pretreatment process, by coagulation/flocculation proved to be a possible ally in increasing COD removal: 90% and 83% for leachate and concentrate, respectively. However, the volume of sludge generated in the process (Leachate - 910 mL.L-1; Concentrate - 870 mL.L-1) was not very favorable. It has been proven that the Fenton reaction in a fluidized bed reactor, coal filling - 40% volume, allows a high efficiency of COD removal.
Industrial effluents are often discharged of in an uncontrolled manner, without the proper treatment and include refractory and toxic compounds, with advanced oxidative processes proving to be an interesting option. These processes, in addition to high economic efficiency and high degradation rates, have low cost and are suitable according to environmental concerns, what makes viable their use. Among these processes, they include the Fenton Process that uses iron (II) as a catalyst and hydrogen peroxide as an oxidizing agent, forming hydroxyl groups that are highly reactive to undesirable compounds in the medium. The present work aimed to optimize the inverse osmosis treatment process at the landfill with the aid of the Fenton process, having been introduced as an innovation the use of fluidized bed reactor. An efficiency analysis was performed using determinant parameters, such as Chemical Oxygen Demand, Sedimentable Solids and volume of sludge formed. For soil leachate and crude concentrate from the reverse osmosis unit, COD values 12000 mg O2.L-1 and 25000 mg O2.L-1, respectively, are indicated which clearly indicates the need and use of the treatment to be implemented. The Fenton tests were performed in batch, optimizing the Fe+2:H202 ratio. For the two effluents, the ratio chosen to continue the tests was 1:10 for demonstrating satisfactory values both for COD removal (Leachate - 57%; Concentrate - 63%), and in the volume of sludge generated (Leachate - 260 mL.L-1; Concentrate - 410 mL.L-1). Regarding the% of COD removal, the test stood out in the presence of activated carbon bed (Leachate - 68%; Concentrate - 82%), not significantly differing in the percentage of sludge formed. The pretreatment process, by coagulation/flocculation proved to be a possible ally in increasing COD removal: 90% and 83% for leachate and concentrate, respectively. However, the volume of sludge generated in the process (Leachate - 910 mL.L-1; Concentrate - 870 mL.L-1) was not very favorable. It has been proven that the Fenton reaction in a fluidized bed reactor, coal filling - 40% volume, allows a high efficiency of COD removal.
Description
Mestrado de dupla diplomação com a UNIFACS - Universidade Salvador
Keywords
Processo de oxidação avançado Processo de Fenton Leito fluidizado Lixiviado Concentrado da osmose inversa