Construction of microsensors and its application in biofilms used in wastewater treatment / Construção de microssensores e sua aplicação para estudo de biofilme empregado no tratamento de água residuária

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

The goal of the current research was the construction of amperometric and potentiometric microsensors to measure dissolved oxygen (DO), hydrogen sulfide (H IND.2S), nitrite, nitrate, ammonium and pH in biofilms applied at wastewater treatment. The biofilms that were analyzed with the constructed microsensors were grown at the surface of flat-plate reactors, which were operated in five distinct experiments under different operational conditions. The growth media that had total Kjeldahl nitrogen (TNK) of 40 ± 10 mg/L and carbon oxygen demand (COD) of 90 ± 5 mg/L was used as feed of the flatplate reactors during the experiments. The reactors were inoculated with sludge originating from activated sludge reactor located in Rio Claro (SP). Alkalinity, pH, COD, NO IND.3POT.-, NO IND.2POT.-analyses of the affluent and effluent of the reactors were carried out for the accompaniment of the operational conditions of the flat-plate reactors. Concomitantly to the last ones, microprofiles of DO, pH, nitrate and ammonium were obtained in the biofilms. The DO microsensors constructed showed a good performance when they were applied to measure oxygen concentrations in the microenvironments in biofilms. Ammonium and pH microelectrodes allowed the verification of the variations of pH and ammonium concentrations in the direction from the bulk liquid to the biofilm that occurred at the flatplate reactors. The nitrate microsensor has not presented selectivity for its primary ions (NO IND.3POT.-) and it was evidenced that the same one detected the concentration of nitrate and nitrite (NO IND.XPOT.-). The nitrite microsensor could not be constructed since the membrane that would be used was not available in the market. The H IND.2Smicroelectrodes had shown efficiency in measuring aqueous solutions with different concentrations of dissolved H IND.2S; however these devices were not applied in biofilms.

ASSUNTO(S)

microsensors wastewater treatment biofilms microssensores flat-plate reactors tratamento de água residuária célula de fluxo biofilmes

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