A novel partial-denitrification strategy for post-anammox to effectively remove nitrogen from landfill leachate

Anaerobic ammonia oxidation (anammox) has shown great promise for nitrogen removal in low C/N wastewater such as landfill leachate. However, 11% of NO3--N is stoichiometrically produced, which decreases the total nitrogen (TN) removal efficiency. In this study, a strategy for post anammox was developed to effectively remove TN from leachate. A tandem conversion of NO3--N to NO2--N (partial denitrification) was accomplished by supplying substrate for subsequent anammox, by supplementing the electron donor deficient condition. This process greatly improved NH4+-N and TN removal from leachate, reaching a 95% efficiency. Quantitative real-time polymerase chain reaction results showed that a high abundance of anammox bacteria, with a titer of 10(9) copy numbers/L, was enriched, accounting for 9.66% of the total bacterial community, and indicating the success of this novel strategy for the TN removal in leachate. (C) 2018 Elsevier B.V. All rights reserved.