Dissolved-air flotation associated with an anaerobic reactor, as applied to sewage treatment

摘要

This paper presents the results of a study performed with a pilot sewage treatment plant consisting of an aerobic reactor followed by a flotation unit. To coagulate the anaerobic effluent, different ferric chloride dosages were applied by adopting two approaches: applying constant dosages during the essay and varying the dosages according to the anaerobic effluent turbidity. To obtain more than 95% TSS, 90% COD and 70% phosphorous removals a critical chemical ratio ranging 0.012 - 0.013 (in terms of Fe/Turbidity ratio) was required. When aiming higher phosphorous removal (above 95%) the required Fe/Turbidity ratio range rose to 0.016-0.018.