FRESENIUS ENVIRONMENTAL BULLETIN, cilt.11, ss.863-867, 2002 (SCI-Expanded)
In this study, an iron removal process, which makes use of the catalytic effect of ferric iron, is proposed. For this purpose, a lab-scale continuous flow aeration/ sedimentation unit with or without recycling was built. The aim of the study was to verify the validity of the findings of batch-type oxidation experiments also for continuous flow conditions. The efficiency of oxidation was about 57-79 % when the system was operated without recycling. Fe(II) removal efficiencies could be increased to 80-89 %, 90-97 % and 98-99.6% for the recycling ratios of 50 %, 80% and 100%, respectively. The increase of Fe(II) removal was explained by an increase of ferric concentration in the aeration tank as a result of recycling. The higher the Fe(III) concentration in the aeration tank the better was the Fe(II) removal efficiency up to a Fe(III) concentration of 300 mg/l. Beyond this level, no significant increase in removal efficiency of ferrous iron was observed with increasing ferric iron concentration.