Fouling behaviour, regeneration options and on-line control of biomass-based power plant effluents using microporous ceramic membranes

Abstract

The work presents an on-line filtration treatment for biomass-based power plant effluents using microporous ceramic symmetric membranes with an emphasis on establishment of fouling mechanisms and regeneration options in the process. The work also establishes the relationships among the membrane filterability, quality of permeate and flux to that of the pore size of ceramic membranes. For these purposes, two types of ceramic membrane configurations, i.e., seven-channeled and single-channeled (hollow type) tubes with identical pore size of 1.2 μm were selected for the experiments. On the other hand, raw effluents generated by the power plant were first pre-filtered using a 0.5 mm sieve and the resultant filtrate was further used for the present microfiltration trials by varying transmembrane pressure (TMP). Differences in the filterability of the effluents by the two membrane configurations at variable levels of TMP were explained using various membrane-fouling models. The filtration resistances that are acting in series were calculated using Darcy's and Poiseuille's law. Establishment of fouling mechanism/s of the membranes and its regeneration by adopting chemical cleaning and backflushing techniques were also an integral part of the study. The results suggest that microfiltration of effluents in a continuous crossflow mode with backflushing in regular intervals offer great advantage over efficiency and effectiveness in monitoring the contaminants in the raw effluents by physical methods. The study hence finds an on-line filtration solution in monitoring biomass-based power plant effluents in a benign way using microporous ceramic membranes.