Study on the Treatment of Refined Sugar Wastewater by Electrodialysis Coupled with Upflow Anaerobic Sludge Blanket and Membrane Bioreactor

In this paper, refined sugar wastewater (RSW) is treated by electrodialysis (ED) coupled with an upflow anaerobic sludge blanket (UASB) and membrane bioreactor (MBR). The salt in RSW was first removed by ED, and then the remaining organic components in RSW were degraded by a combined UASB and MBR system. In the batch operation of ED, the RSW was desalinated to a certain level (conductivity < 6 mS center dot cm(-1)) at different dilute to concentrated stream volume ratios (V-D/V-C). At the volume ratio of 5:1, the salt migration rate J(R) and COD migration rate J(COD) were 283.9 g center dot h(-1)center dot m(-2) and 13.84 g center dot h(-1)center dot m(-2), respectively, and the separation factor a (defined as J(COD)/J(R)) reached a minimum value of 0.0487. The ion exchange capacity (IEC) of ion exchange membranes (IEMs) after 5 months of usage showed a slight change from 2.3 mmol center dot g(-1) to 1.8 mmol center dot g(-1). After the ED treatment, the effluent from the tank of the dilute stream was introduced into the combined UASB-MBR system. In the stabilization stage, the average COD of UASB effluent was 2048 mg center dot L-1, and the effluent COD of MBR was maintained below 44-69 mg center dot L-1, which met the discharge standard of water contaminants for the sugar industry. The coupled method reported here provides a viable idea and an effective reference for treating RSW and other similar industrial wastewaters with high salinity and organic contents.

Automated summary

In this study, refined sugar wastewater (RSW) was treated using electrodialysis (ED) coupled with an upflow anaerobic sludge blanket (UASB) and membrane bioreactor (MBR). The salt in RSW was first removed by ED, followed by degradation of remaining organic components using the combined UASB-MBR system. The results showed successful removal of salt and organic contaminants, meeting the discharge standard for the sugar industry. This coupled method provides a viable and effective approach for treating RSW and similar high salinity and organic content wastewaters.