Cathodic fluidized granular activated carbon assisted-membrane bioelectrochemical reactor for wastewater treatment

• Fluidized granular activated carbon (GAC) can effectively reduce membrane fouling.
• GAC can act as a part of the cathodic electrode for enhancing electricity production.
• The membrane bioelectrochemical reactor achieves nearly 100% removal of organics.
• Energy consumption by the MBER is estimated as 0.38 kWh m−3 or 0.25 kWh kgCOD−1.

A membrane bioelectrochemical reactor (MBER) is a system integrating membrane filtration into microbial fuel cells. To control membrane fouling, fluidized granular activated carbon (GAC) was applied to the cathodic compartment of an MBER, which was examined for contaminant removal and electricity generation with low or medium strength synthetic wastewater. The MBER was operated for more than 160 days and achieved nearly 100% removal of organic compounds, regardless of presence/absence of GAC. However, fluidized GAC alleviated the membrane fouling issue and maintained transmembrane pressure (TMP) between 10 and 15 kPa with 24 g of GAC. The presence of GAC also enhanced current generation from 200.3 to 256.0 A m−3, because some GAC might have functioned as a part of the cathodic electrode through physical contact with the electrode during fluidization. A higher aeration intensity could benefit both membrane fouling control (via scouring effect) and electricity generation (via oxygen supply), but required a higher energy demand. The energy consumption of the MBER including pumping and aeration was estimated to be 0.38 kWh m−3 or 0.25 kWh kgCOD−1, lower than that of conventional membrane bioreactors (MBRs). Those results encourage further investigation and development of the MBER technology to treat wastewater in an energy efficient way.

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