Inhibitory Effect of Tetracycline on Activated Sludge System and Its Removal Efficiency

The influence of tetracycline( TC) on COD removal and sludge yield in activated sludge system was investigated,and the removal efficiency of TC by activated sludge was studied.The results showed that the TC had significant inhibitory effect on the sludge yield and its ability in substrate removal.With the increase of TC concentration and the reduction of MLSS,the inhibitory effect became apparent.When TC concentration was increased from 0 to 20 mg / L,the removal rate of COD was decreased from 89.2% to 39.1%,the apparent sludge yield was decreased from 0.53 to 0 gMLSS / gCOD,and sludge growth stopped.The removal of TC from wastewater was achieved mainly via rapid adsorption on the sludge,and the removal rates of TC were 95%,91.24% and 90.54% when its initial concentrations were 5,10 and 20 mg / L,respectively.With the increase of TC concentration and the reduction of MLSS,the equilibrium time was prolonged,adsorption capacity increased and adsorption rate reduced.The adsorption of TC by activated sludge fit a pseudo second-order kinetics model( R2 0.999).