BIOLOGICAL DENITRIFICATION IN A FLUIDIZED-BED WITH SAND AS CARRIER MATERIAL

A mathematical model for biological fluidized bed denitrification was tested in a 400 l h-1 expanded bed. Nitrate proved to inhibit the nitrite-reductase activity. Competitive inhibition showed a better correspondence between theory and experiment than uncompetitive inhibition. The efficiency of the fluidized bed for denitrification purposes was much higher than in the case of conventional mixed liquor processes. Both theory and experiments showed a substantial accumulation of the intermediary product nitrite, a potential health hazard. Nitrite-N maxima in the column were determined analytically and amounted to about 20% of the influent nitrate-N concentration. © 1979.