Experimental evaluation of the nitrification kinetics for tannery wastewaters

The paper outlines results of the experimental assessment of nitrification kinetics applicable to tannery wastewaters and thr inhibitory effects of se lected pollutants on nitrification. The average net growth rate of nitrifie rs was measured as 0.32 d(-1) at 20 degrees C and 0.10 d(-1) at 10 degrees C for tannery wastewaters subjected to plain settling. This: kinetic coeffi cient was observed to increase to 0.43 d(-1) at 20 degrees C with chemical settling. Parallel experiments with synthetic waste containing only NH4Cl r evealed the strong inhibitory character of tannery wastewater. Chromium was observed to be partly responsible for the inhibitory effect which was main ly induced by chloride, inherently present in this type of wastewaters.