Treatment of molasses wastewater in a membrane bioreactor: Influence of membrane pore size

Due to high chemical oxygen demand (COD) and its low biodegradability, molasses wastewater is usually classified as a high-strength industrial wastewater. The possibility and efficiency of a membrane bioreactor (MBR), containing lab-made membrane modules, in treating molasses containing wastewater was studied. The research was conducted in two phases, namely a first period of fed-batch operation followed by a second with continuous MBR operation. The results showed that more than 80, 90 and 30%, respectively, of the COD, total nitrogen (TN) and color were removed. There was a clear influence of the membrane pore size on trans-membrane pressure (TMP) build-up. Scanning electron microscopy and Fourier transformed infrared (FT-IR) analyses revealed no significant differences in organic constituents between the membrane cake layer and the activated sludge.

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► Membrane bioreactor was used to treat molasses containing wastewater.
► More than 80.9%, 90.1%, and 30% of COD, TN and color, respectively, were removed.
► Lower membrane fouling was observed for higher membrane pore size.
► Foulant autopsy showed no significant differences between the sludge and the cake.