Tanja Kurbus,* Janez Vrtovek and Milenko Ro
National Institute of Chemistry, PO BOX 660, Hajdrihova 19, SI-1001 Ljubljana,
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Nitrification/denitrification processes at high flocculent biomass concentrations (11.613.4 g L1) were studied in pilot Sequencing Batch Reactor (SBR). Optimal operating conditions for maximal nitrogen elimination efficiency were as follows: organic loading of 0.9 g COD L1 d1, nitrogen loading of 0.11 gN L1 d1, MLSS of 12 g L1 and SRT of 52 days. Medium sized sludge flocs (0.10.4 mm) with excellent settle ability (SVI = 27 mL g1) were formed during the experiment. Volumetric nitrogen removal rate of 90 mg NL1 d1 was achieved, which is twice as much as in SBR operating at low MLSS of 3.5 gL1 and low SRT of 21 days. This process offers an attractive option for the treatment of highly polluted wastewaters with lower investment and operating costs.
Keywords: High MLSS, denitrification, nitrification, SBR.