Advanced treatment of dyehouse effluents by Fe(II) and Mn(II)-catalyzed ozonation and the H2O2/O-3 process

Treatment of synthetic dyehouse effluent containing six reactive dyestuffs and their assisting chemicals by O-3/Fe(II), O-3/Mn(II), and O-3/H2O2 advan ced oxidation processes was investigated. All oxidation processes were capa ble of completely decolourizing the wastewater within 30 min. Decolourizati on proceeded fastest by the O-3/Mn(II) process, whereas the O-3/H2O2 combin ation was more efficient in the removal of DOC (Dissolved Organic carbon) a nd UV254nm which were 11 and 53%, respectively, for one hour treatment time . Application of Fe(II)-catalyzed ozonation provided an effective means of removing colour and COD (Chemical Oxygen Demand) by a five- and nine-fold e nhancement, respectively, compared with conventional coagulation applied at the same coagulant doses. Formation of toxic oxidation products was not ob served during the course of treatment with all investigated advanced oxidat ion processes.