Advanced nitrogen removal from landfill leachate via a two-stage combined process of partial nitrification-Anammox (PNA) and partial denitrification-Anammox (PDA)

• Published in: The Science of the total environment 2022-03, Vol.810, p.151186-151186, Article 151186
• Main Authors: Qiu, Jingang, Li, Xiyao, Peng, Yongzhen, Jiang, Hao
• Format: Article
• Language: English
• Subjects: Anaerobic Ammonia Oxidation; Anammox; Bioreactors; Denitrification; Landfill leachate; Nitrification; Nitrogen; Oxidation-Reduction; Partial denitrification; Partial nitrification; Sewage; Two-stage treatment; Waste Water; Water Pollutants, Chemical
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2021.151186

In this study, a two-stage combined process of partial nitrification-Anammox (PNA) and partial denitrification-Anammox (PDA) was established achieving advanced nitrogen removal from landfill leachate. The PNA sludge used to treat reject water adapted to the leachate in 37 days, resulting in fast start-up of the PNA process with a nitrogen removal rate (NRR) of 0.22 kgN/(m3·d). Partial denitrification (PD) was induced using sodium acetate and proceeded in a stepwise manner using sludge fermentation liquid (SFL), achieving a NO3−-N to NO2−-N transformation ratio (NTR) of 52.1 ± 1.1% within 16 days. PDA was established via the addition of mature Anammox biofilms. The nitrogen removal efficiency (NRE) of this system was 97.6 ± 1.5%, of which PNA and PDA contributed 74.8 ± 4.0% and 18.7 ± 4.1%, respectively. Nitrosomonas (2.6% in PNA), Thauera (16.0% in PDA) and Candidatus Brocadia (23.0% in PNA, 1.4% in PDA) were dominant in the two-stage system. This study provides valuable and novel insights, supporting the practical application of PNA-PDA processes in landfill sites. [Display omitted] •A two-stage combined PNA and PDA process was established to treat leachate.•Fast adaptation of mature PNA sludge to leachate shortened the PNA start-up time.•The carbon source of PD could be transformed from sodium acetate to SFL.•PDA acted as polishing process to achieve the effluent TN of 14.0 ± 2.0 mg/L.•Nitrosomonas, Thauera and Candidatus Brocadia were dominant in this system.