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

Under anaerobic conditions, ammonium (NFU-) can react with nitrite (NO2-) and sulfate (SO42-), termed nitrite-anammox (NirAnammox) and sulfate-anammox (Sulfammox), respectively. However, how to remove NH4 and SO4 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 degrees C). NH4+, total nitrogen (TN), and SO42- 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 NH4+ respectively. Therefore, because leachate contains high concentrations of NH4+ and SO42-, 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. (C) 2019 Published by Elsevier Ltd.