Table 2. Effect of different feeding conditions on the effluent characteristics of the cathode and the MFC performance.
| Period | Flow (L·d−1) | COD (mg COD·L−1) | NO3 − (mg N-NO3 −·L−1) | NO2 − (mg N-NO2·L−1) | N2O (mg N-N2O·L−1) | N2 (mg N-N2·L−1) | Cd (A·m−3 NCC) | CE (%) |
| Period 1 (Autotrophic with NO3 −) | 2.0±0.3 | n.d. | 22.6±0.3 | 0.2±0.1 | 0.6±0.2 | 3.5±1.2 | 15.0±2.3 | 85±11 |
| Period 2 (Heterotrophic with NO3 −) | 1.4±0.5 | 31±22 | 20.7±4.8 | 2.1±3.4 | 4.0±1.9 | 3.8±1.8 | 11.0±7.0 | 58±17 |
| Period 3 (Autotrophic with NO2 −) | 1.2±0.2 | n.d. | 0.0±0.2 | 4.6±4.8 | 13.0±5.9 | 5.6±2.6 | 14.1±8.2 | 41±17 |
Concentrations of N2O and N2 were estimated on the basis of the electron balance at the cathode according to the method proposed of Virdis et al. [28].
NO3 −, nitrate; NO2 −, nitrite; N2O, nitrous oxide; N2, dinitrogen gas; Cd, current density; CE, coulombic efficiency.