Low energy treatment of landfill leachate using simultaneous partial nitrification and partial denitrification with anaerobic ammonia oxidation

• Published in: Environment international 2019-06, Vol.127, p.452-461
• Main Authors: Wu, Lina, Li, Zhi, Huang, Shan, Shen, Mingyu, Yan, Zhibin, Li, Jin, Peng, Yongzhen
• Format: Article
• Language: English
• Subjects: Anaerobic ammonia oxidation; Denitrification; Landfill leachate; Partial nitrification
• ISSN: 0160-4120; 1873-6750
• DOI: 10.1016/j.envint.2019.02.071

An up-flow anaerobic sludge blanket reactor (UASB), anoxic/oxic (A/O)–anaerobic ammonia oxidation reactor (ANAOR or anammox reactor), and anaerobic sequencing batch reactor (ASBR) were employed in the treatment of landfill leachate with partial nitrification-anammox and half-denitrification-anammox. The Chemical Oxygen Demand (COD) concentration, ammonium nitrogen (NH4+-N) concentration, and total nitrogen (TN) concentration of the basal leachate was 2200–2500 mg/L, 1200–1300 mg/L, and 1300–1400 mg/L, respectively. After a 1:2 dilution using domestic sewage, the COD, NH4+-N, and TN concentrations in the influent were 800–1000 mg/L, 400–430 mg/L, and 420–440 mg/L, respectively. After treatment, the final COD, NH4+-N, and TN were decreased to 90–100 mg/L, 13–14 mg/L, and 35–38 mg/L, respectively. In the ASBR, organic carbon sources in sewage-diluted landfill leachate were introduced for the conversion of nitrate nitrogen (NO3−-N) into nitrite nitrogen (NO2−-N). This enabled the continued reaction of NO2−-N with NH4+-N from the newly introduced sewage-diluted landfill leachate via anammox. As a result, complete TN removal was achieved in the system. Microbial diversity analysis indicated that the relative abundance of ammonia-oxidizing bacteria (AOB) was four to five times greater than nitrite-oxidizing bacteria (NOB) in the A/O reactor, showing that partial nitrification was prevalent. The relative abundance of the anammox bacterium Candidatus Kuenenia gradually increased in each reactor, reaching a maximum of 1.17%–1.39%. Using this set-up, we achieved advanced, efficient, and economical, COD reduction and nitrogen removal. Taken together, the findings provide important insights into the optimal operation of landfill leachate treatments. •Leachate was treated by partial nitrification-anammox and half-denitrification-anammox.•The TN removal ratio of 92% was achieved without the addition of reagent.•Diluted leachate was used as a limited carbon source to convert NO3-–N to NO2-–N.•The relative abundance of AOB was four times that of NOB in A/O reactor.•The relative abundance of the typical anammox genus Candidatus Kuenenia gradually increased, reaching 1.17%-1.39%.