Abstract
Nitrogen removal through anammox is well-known for its low cost and less CO 2 emissions, in this process ammonium converted into nitrogen gas with the help of anammox. It is hypothesized that the presence of electrodes in upflow anaerobic sludge blanket-microbial fuel cell (UASB-MFC) might increase nitrogen removal. In order to check this, two experimental setup were used to remove ammonium with electrode (UASB-MFC) and without electrode (UASB), under anammox condition. Different parameters were analyzed including nitrate, nitrite, total nitrogen and voltage. After 164 days, the NH 4 + concentration in effluent was 3.20 mg/L and 4.23 mg/L, total inorganic nitrogen was 11.9 mg/L and 8.45 mg/L in UASB and UASB-MFC effluent respectively. Bacterial growth rate was calculated through biokinetic modelling, indicating anammox growth rate 0.00294 g VSS/m 3 .d in UASB-MFC with maximum voltage production of 774 mV. Metagenomic study was performed through 16S rRNA genome sequencing showed, Firmicutes phylum was high in both reactors, while J o u r n a l P r e-p r o o f Planctomycetes, abundance 2.8% showing anammox growth achievement only in UASB-MFC. Lower concentration of nitrate, nitrite and total inorganic nitrogen were found in the UASB-MFC effluent which suggested the higher conversion of ammonium into nitrogen gas. It is concluded that the presence of an electrode oxidizes more nitrogen; hence total nitrogen was removed much more than in the absence of an electrode.