Advanced nitrogen removal from mature landfill leachate based on novel step-draining partial nitrification-denitrification and Anammox process: Significance of low volume exchange ratio

• Published in: Bioresource technology 2022-11, Vol.364, p.128025, Article 128025
• Main Authors: Jiang, Hao, Li, Xiyao, Zhang, Fangzhai, Wang, Zhong, Ren, Shang, Qiu, Jingang, Wang, Shuying, Peng, Yongzhen
• Format: Article
• Language: English
• Subjects: Anammox; Granule sludge; Landfill leachate; Partial nitrification and denitrification; Step-draining mode
• ISSN: 0960-8524; 1873-2976; 1873-2976
• DOI: 10.1016/j.biortech.2022.128025

[Display omitted] •Step-draining PND-AMX system achieved NRE and NRR of 98.3% and 3.07 kgN/(m3∙d).•COD and TIN were removed synergistically with full use of carbon source at 25% VER.•Adjusting VER of the two effluents obtained optimal NH4+ to NO2− ratio of Anammox.•ORP curves along depth of particles revealed sludge granulation mechanism.•Partial Anammox contributed 21.0% to TIN removal and had practical significance. To save external carbon source dosage and simplify NH4+ to NO2− ratio control strategy, this study established a novel step-draining based partial nitrification-denitrification and Anammox (PND-AMX) system for advanced nitrogen removal from mature landfill leachate. Separation of partial nitrification and denitrification was realized based on step-draining, achieving 74.8 % nitrogen removal. 25 % was the optimal volume exchange ratio for synergistic removal of organics and nitrogen, allowing full use of carbon source. NH4+ to NO2− ratio was easily controlled by varying the volume ratio of the first and second effluent of PND reactor. Brocadia, Kuenenia and Jettenia collectively accounted for 13.61 % in AMX reactor, contributing 21.0 % of nitrogen removal. Nitrogen removal efficiency and nitrogen removal rate reached 98.3 ± 1.2 % and 3.07 ± 0.09 kgN/(m3∙d), respectively. Partial Anammox process based on step-draining was easier to realize and of practical significance for application in treatment of landfill leachate.