Advanced nitrogen removal from landfill leachate using real-time controlled three-stage sequence batch reactor (SBR) system.

Abstract A three-stage sequencing batch reactor (SBR), comprising pretreating SBR (SBR pre ), nitritation SBR (SBR ni ), and anaerobic ammonium oxidation (Anammox) SBR (SBR ana ), was developed for the nitrogen removal from mature landfill leachate. The concentrations of ammonia and chemical oxygen demand (COD) in the leachate were 2000 ± 100 and 2200 ± 200 mg/L, respectively. About 100 mg/L of organic substance was removed from SBR pre to reduce the negative effect on the Anammox process under real-time control. After acclimation for 40 days, the nitrite to nitrogen oxide ratio ( NO 2 - /NO x ) in SBR ni was above 0.95. The nitrogen removal efficiency reached 90% in SBR ana , and nitrogen load rate and nitrogen removal rate were 0.81 and 0.76 kg N/(m 3  d), respectively. The continuous filling process was used to avoid the nitrite inhibition on the Anammox activity. The quantitative PCR analysis of Anammox indicated the average Anammox gene ratio increased from 0.23% to 4.77% after 220 days operation.