Inhibition Of Nitrification By Heavy-Metal Cations

The aim of this work was to make a contribution to the knowledge of inhibition by some inorganic pollutants of nitrifying bacteria which are free or fixed on an adsorbant support. For the inhibition tests, we used the following inorganic salts: Nickel, Ni 2+ ; Copper, Cu 2+ ; Cadmium, Cd 2+ and Zinc, Zn 2+ as sulphates (Figs 1, 2). The preliminary tests give the solubility of the cations in the feed solutions to the pilot units (biological filters and activated sludge). The other experiments, dynamic or in batch, try to establish the inhibitory effects observed with respect to a nitrifying biomass inactivation.