Nitritation–denitritation in landfill leachate with glycerine as a carbon source

The effects of limited oxygen concentration (0.7 mg O2/L) in the aeration phase of the SBR cycle and glycerine as an additional carbon source on the effectiveness of nitritation–denitritation and sludge production during municipal landfill leachate treatment were examined. As carbon sources, sodium acetate (Ac) and sodium acetate (Ac) with glycerine (Gly) in the proportions of 3:1 (v/v) and 1:1 (v/v) were added. Low dissolved oxygen concentration inhibited the second stage of nitrification and nitrites were the main final products. Nitritation effectiveness was ca. 98–99%. Denitritation efficiency was relatively low (61%) in the reactor fed with Ac, which may be linked with high sludge production (Yobs – 0.6 mg VSS/mg COD). Glycerine addition (Ac:Gly 1:1, v/v) caused an increase in process efficiency to 75.6% with a concurrent significant decrease in biomass production (Yobs – 0.46 mg VSS/mg COD).