Pilot-scale PSSBR(Phase Separated Sequencing Batch Reactor) was operated to evaluate requirement of external carbon sources(${Delta}gCOD/{Delta}gNO_3^{-}-N$) in denitrification. Methanol and fermented food waste were used as external carbon sources. Methanol and fermented food waste were fed to the anoxic state of first reactor and concentration were 50 and 40 mgCOD/L on the basis of concentration in reactor, respectively. In case that external carbon source was not used, average $NO_3^{-}-N$ concentration in effluent was 22.49 mg/L. When methanol and fermented food waste were fed, average $NO_3^{-}-N$ concentration in effluent were 10.13 mg/L and 6.3 mg/L, respectively and requirement of external carbon sources were 4.04 and 2.5 ${Delta}gCOD/{Delta}gNO_3^{-}-N$, respectively. Fermented food waste was better than methanol in denitrification efficiency. Therefore fermented food waste could be one of the excellent external carbon sources for nitrogen removal in biological nutrient removal process.