BACKGROUNDMelanoidins are brown colored polymers found in wastewater produced by the fermentation industry. Melanoidins are recalcitrant compounds that are toxic to living systems, therefore, must be treated before disposal. The aim of the present study is the removal of melanoidins from simulated effluents by a hybrid flotation-filtration process. Coagulation-flocculation or adsorption processes were evaluated as pre-treatment stages. RESULTSIn the coagulation hybrid flotation/filtration process, coagulation is realized by ferric ions and a cationic flocculant, flotation by sodium dodecyl sulfate and filtration by a 250 mu m filter. In the adsorption hybrid flotation/filtration process, adsorption is performed by powdered activated carbon, flotation by sodium dodecyl sulfate and filtration by a 16-40 mu m filter. CONCLUSIONThe results show effective melanoidin removal (about 90%) for both processes and limited filter fouling in the second process, which was corrected by air back-flushing. (c) 2018 Society of Chemical Industry