Determinação do fluxo crítico e fluxo limite em membrana de microfiltração utilizada no pós-tratamento de esgoto doméstico

• Autor(a) principal: Oliveira, Amanda Tobias Costa de
• Data de Publicação: 2016
• Tipo de documento: Trabalho de conclusão de curso
• Idioma: por
• Título da fonte: Repositório Institucional da UFRN
• Texto Completo: https://repositorio.ufrn.br/handle/123456789/40821
• topic: Fluxo crítico em membranas; Fluxo limite em membranas; Microfiltração; Fouling; Método de degraus de pressão; Velocidade tangencial; Membrane threshold flux; Membrane limiting flux; Microfiltration; Fouling; Pressure-step method; Crossflow velocity; CNPQ::ENGENHARIAS::ENGENHARIA SANITARIA::TRATAMENTO DE AGUAS DE ABASTECIMENTO E RESIDUARIAS

The threshold flux and limiting flux concepts represent an important advance in membrane technology, for they allow the identification of optimal operating conditions for fouling control, one of the main obstacles in membrane application for water and wastewater treatment. In this study, the pressure-step method was applied to a microfiltration membrane system fed with anaerobic filter’s effluent in order to determine the threshold and limiting fluxes. Throughout the experiments, the pressure was gradually increased to a maximum value and then it was decreased to the initial value, while the permeate flux was measured. Three fouling parameters were defined and calculated from the pressure-step tests results: average flux in the step (Jm), fouling rate (dJ/dt) and initial flux increase (ΔJ0). The results showed smaller flux values, for the same pressure, in the descending phase than in the ascending phase, indicating the formation of a irreversible fouling layer. Furthermore, Jm did not reach a stabilization plateau, which would indicate the limiting flux. Since the crossflow velocity could not be kept constant, the fouling rate (dJ/dt) decreased with pressure increase, affecting the ΔJ0 results, which would indicate the threshold flux. It was concluded that it is not possible to determine the threshold flux and the limiting flux without constant crossflow velocity.