Palm oil mill effluent treatment using a two-stage microbial fuel cells system integrated with immobilized biological aerated filters

An integrated system of two-stage microbial fuel cells (MFCs) and immobilized biological aerated filters (I-BAFs) was used to treat palm oil mill effluent (POME) at laboratory scale. By replacing the conventional two-stage up-flow anaerobic sludge blanket (UASB) with a newly proposed upflow membrane-less microbial fuel cell (UML-MFC) in the integrated system, significant improvements on NH3–N removal were observed and direct electricity generation implemented in both MFC1 and MFC2. Moreover, the coupled iron–carbon micro-electrolysis in the cathode of MFC2 further enhanced treatment efficiency of organic compounds. The I-BAFs played a major role in further removal of NH3–N and COD. For influent COD and NH3–N of 10,000 and 125 mg/L, respectively, the final effluents COD and NH3–N were below 350 and 8 mg/L, with removal rates higher than 96.5% and 93.6%. The GC–MS analysis indicated that most of the contaminants were satisfactorily biodegraded by the integrated system.