However, the length of the phases {feast (aerobic) famine (anoxic)} should be adjusted to ensure the maintenance of the synthesised PHAs under aerobic conditions and their depletion in the anoxic phase. Although the rate of endogenous denitrification is low, the internal storage compounds can be used to meet the need of denitrification via nitrite (Chen et al., 2013), which requires less organic carbon than the conventional denitrification. Post-anoxic denitrification via nitrite driven by storage compounds was successfully achieved in a SBR operated with an aerobic/anoxic/extended-idle regime by Chen et al. (2013) treating wastewater from a septic tank. The results indicated that this treatment process could achieve desirable and stable nitrogen removal efficiency.