Biological nitrogen removal from landfill leachate using anaerobic–aerobic process: Denitritation via organics in raw leachate and intracellular storage polymers of microorganisms

A system which combined ASBR with pulsed SBR (PSBR) was introduced to enhance COD and nitrogen removal from the real landfill leachate. ASBR was used to degrade the organics from raw leachate mainly. Three equal feeds mode was applied in PSBR operation. The results obtained from the joint operation period (157 days) show that the COD removal rate of ASBR was 83–88% under the specific loading rate of 0.43–0.62 gCOD gVSS−1 day−1. PSBR’s operation can be divided into four phases according to the different influent NH4+-N which increased to 800–1000 mg L−1 finally, and total nitrogen (TN) removal rate of more than 90% with the effluent TN of less than 40 mg L−1 was obtained. PHB and glycogen can act as electron donor for endogenous denitritation orderly with the hypothetical function from DNGAOs. Consequently, the system achieved COD and TN removal rate of 89.61–96.73% and 97.03–98.87%, respectively, without any extra carbon source addition.