Advanced nitrogen removal via nitrite using stored polymers in a modified sequencing batch reactor treating landfill leachate

•Advanced nitrogen removal from landfill leachate with low C/N ratio was achieved.•SBR process was modified by adding anaerobic stage after feeding to store organics.•PHB and glycogen could both be the carbon source for endogenous denitritation.•GAOs are the functional species for nitrogen removal, and enriched via modified SBR.•The nitrite accumulation reached above 98%, which was basis of nitrogen removal.