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A novel bio-electrochemical system with sand/activated carbon separator, Al anode and bio-anode integrated micro-electrolysis/electro-flocculation cost effectively treated high load wastewater with energy recovery

Gao, Changfei, Liu, Lifen, Yang, Fenglin
Bioresource technology 2018 v.249 pp. 24-34
activated carbon, aeration, air, aluminum, ammonium nitrogen, bioanodes, catalysts, cathodes, chemical oxygen demand, electric power, electrical resistance, energy recovery, fouling, granules, iron, liquids, manganese, microorganisms, oxidation, power generation, sand, wastewater
A novel bio-electrochemical system (BES) was developed by integrating micro-electrolysis/electro-flocculation from attaching a sacrificing Al anode to the bio-anode, it effectively treated high load wastewater with energy recovery (maximum power density of 365.1 mW/m³ and a maximum cell voltage of 0.97 V), and achieving high removals of COD (>99.4%), NH₄⁺-N (>98.7%) and TP (>98.6%). The anode chamber contains microbes, activated carbon (AC)/graphite granules and Al anode. It was separated from the cathode chamber containing bifunctional catalytic and filtration membrane cathode (loaded with Fe/Mn/C/F/O catalyst) by a multi-medium chamber (MMC) filled with manganese sand and activated carbon granules, which replaced expensive PEM and reduced cost. An air contact oxidation bed for aeration was still adopted before liquid entering the cathode chamber. micro-electrolysis/electro-flocculation helps in achieving high removal efficiencies and contributes to membrane fouling migration. The increase of activated carbon in the separator MMC increased power generation and reduced system electric resistance.