Low temperature advanced nitrogen and sulfate removal from landfill leachate by nitrite-anammox and sulfate-anammox.

Under anaerobic conditions, ammonium (NH) can react with nitrite (NO) and sulfate (SO), termed nitrite-anammox (NirAnammox) and sulfate-anammox (Sulfammox), respectively. However, how to remove NH and SO together from leachate is unclear. In this study, NirAnammox and Sulfammox cooperatively achieved nitrogen and sulfate removal from leachate using a biological process at low temperature (14-15 °C). NH, total nitrogen (TN), and SO concentrations in the influent were 610-700, 670-900, 1870-1920 mg/L, respectively, and 10 ± 1, 35 ± 3, and 897.7 ± 10 mg/L, respectively, in the effluent. Sulfammox, and NirAnammox (including partial nitrification) removed 44.2% and 35.46% of the NH, respectively. Therefore, because leachate contains high concentrations of NH and SO, NirAnammox and Sulfammox can easily occur together, with nitrogen removal by Sulfammox being more than NirAnammox. The relative abundance of dominant bacteria of the Sulfammox were 10-20 times that of Candidatus Kuenenia (NirAnammox) in each reactor. Organic matter negatively affected NirAnammox, but not Sulfammox. Dissolved oxygen negatively affected both.