Study of the performance of bench-scale electro-membranes bioreactor in leachate treatment

In the present study, the integration of the electrochemical process with a membrane bioreactor was used as a new technology for leachate treatment. In the electro-membrane bioreactor (EMBR), aluminum electrodes were used as anodes and cathodes. The EMBR was operated at a current density of ۰.۵ mA/cm۲ and a solids retention time of ۹۰ days to remove common contaminants such as ammonia-nitrogen (NH۳-N), chemical oxygen demand (COD), phosphate (PO۴۳--P), and ultraviolet absorbance at ۲۵۴ nm (UV۲۵۴). The maximum removal efficiencies of COD and NH۳-N were above ۹۸%. The average removal efficiency of PO۴۳--P by the EMBR system was ۹۳%, which was significant compared to previous studies. The removal rate of humic substances based on UV۲۵۴ was provided at approximately ۹۶.۹۵%. The trans-membrane pressure rate was acceptable for ۸۰ days in the EMBR, which could be related to sludge size improvement and filtration resistance through the occurrence of electrocoagulation, electrophoresis, and electroosmosis mechanisms. The mean removal efficiencies in the EMBR were ۹۰, ۹۱.۲۵, ۹۶, and ۸۷.۵ % for chromium (Cr), cadmium (Cd), zinc (Zn), and iron (Fe), respectively. The slight change of mixed liquor-suspended solids (MLSS) in the leachate treatment reactor showed that the microorganisms in the new EMBR system had high adaptation. Based on the results, the EMBR is a promising technology to improve leachate treatment performance due to its excellent removal efficiency of common contaminants, metal removal, and reducing fouling.

Keywords:

Electro MBR , Leachate treatment , Electric field , Membrane fouling , Metal removal