Biological Removal of Ammonia from Municipal Landfill Leachate (Kozodrza, Poland) at Limited Oxygen Access and Presence of Kaldnes Media

The effect of filling the sequential batch reactor (SBR) with Kaldnes biomass carrier media on the effectiveness of landfill leachate treatment was examined. The experiment was carried out under limited access to oxygen (0.5–1.0 mg·L^-1). The raw leachate was characterized with the COD concentration at the level of 7758 mg·L^-1, BOD5 – 904 mg·L^-1, and NH₄⁺ – 980 mg·L^-1. The nitrogen loading rate (NLR) was low and amounted to 0.3 kg·m^-3·d^-1. The fill fraction had no effect on the concentration of contaminants in effluents, but turned out to be significant as far as the ammonia nitrogen loss rate was concerned. During the first six hours of SBR operation, the reaction rate increased from 0.64 mg·L^-1·h^-1 to 6.85 mg·L^-1·h^-1 with increasing fill fraction. In the remaining time (7–23 h) in the case of the reactor operating only with suspended activated sludge, and the one with 10% of filtration media, the reaction rate was comparable, i.e. 27.24 mg·L^-1·h^-1 and 27.02 mg·L^-1·h^-1, respectively. Increasing the fill fraction to 20% resulted in a decrease of the reaction rate to 18.28 mg· L^-1·h^-1.