The variation of COD with electrolysis time is shown in
Fig. 4. COD decreases with increasing electrolysis time
and reaches to a constant value. There is a sharp decrease
in COD at the first 5 minutes of the process and after that
there is a gradual decrease in the level. With the electrode
combination Fe-Fe for different currents at different time
intervals used and percentage removal of Chemical
oxygen demand values are depicted in Fig. 5. From the
graph initially the percentage removal of chemical oxygen
demand had increased and gradually the percentage
removal decreases.