Partial nitrification coupled with denitrification and anammox to treat landfill leachate in a tower biofilter reactor (TBFR)

Abstract

Abstract This study investigated the performance of partial nitrification (PN), carbon oxidation, denitrification and anammox in a continuous tower biofilter reactor (TBFR) with large height-to-diameter ratio of 13 in treating actual landfill leachate. The nitrogen loading rate (NLR) and organic loading rate (OLR) varied from 0.44 to 1.31\xa0kg-N/(m3·day) and 1.59 to 4.76\xa0kg/(m3·day), respectively. The average removal rates of total nitrogen (TN) and chemical oxygen demand (COD) in the TBFR reached 87.47% and 88.45% at the maximum NLR and OLR of 1.31\xa0kg-N/(m3·day) and 4.76\xa0kg/(m3·day), respectively. Variation of water quality along the TBFR in different operating conditions indicated that approximately 45% - 60% of the influent NH4+-N was converted into NO2−-N, and nearly 55% - 70% of the influent COD was removed in the 0–40\xa0cm zone, which provided suitable conditions for the subsequent anaerobic anammox and denitrification processes in the 40–160\xa0cm zone. Overall, the TBFR with a large height-to-diameter ratio demonstrated an effective technology for the treatment of landfill leachate by creating distinct aerobic and anaerobic zones in a single reactor.