DENITRIFICATION BY PACKED-BED REACTORS IN THE PRESENCE OF CHROMIUM(VI) - RESISTANCE TO INHIBITION

The effect of chromium Cr**6** plus on bacterial denitrification was investigated. The long-term influence of chromium presence was observed in packed bed reactors using methanol, ethanol, n-propanol, n-butanol, sec-butanol, tert-butanol, iso-butanol and n-pentanol as the carbon and energy sources for denitrifiers. Short-term influence was investigated by the inhibition coefficient K//i determination within activated sludge under anoxic conditions. The measured inhibition constant K//i was equal to 84. 2 mg l** minus **1 Cr**6** plus , independently of the kind of organic compound utilized as the electron donor for the bacterial system. The concepts of the reactor resistance to inhibition (RRI) and the resistance to inhibition (RI) have been evaluated. Refs.