Fate of inert COD fractions in two-stage biological treatment of a strong wastewater

In this study, the effluent of an alcohol distillery after passing through a chemical treatment is characterized in terms of its inert COD fractions a nd the changes likely to be induced by two-stage biological treatment on th e magnitude of these fractions are observed. The experimentally obtained re sults indicated that the anaerobic treatment gives lower soluble inert COD fractions than a corresponding aerobic treatment for the investigated waste water. Therefore, the preference of anaerobic treatment instead of an aerob ic one as the first stage is ascertained. The anaerobic first stage has a C OD removal efficiency of 96 % whereas with a subsequent aerobic treatment 7 9 % removal can be achieved on the basis of the stoichiometry of the inert GOD. The anaerobic fill-scale plant performance of 80 % can be improved up to 96 %.