Comparison of electrocoagulation, coagulation and the Fenton process for the treatment of reactive dyebath effluent

In this paper, experimental studies were performed on a simulated reactive dyebath effluent to compare coagulation-flocculation and Fenton's oxidation with electrocoagulation using stainless steel (SS 304) and aluminium electrodes in terms of colour and COD removals as well as AOX formation potential and improvement of biological treatability. Results have indicated that FeCl₃ and alum coagulation had little effect on colour removal whereas comparable colour removal efficiencies with those of electrocoagulation with steel electrodes and Fenton's oxidation were attained by FeSO₄ coagulation. Almost complete colour removals accompanied with 77% COD abatement were obtained by both electrocoagulation with steel electrodes and Fenton's oxidation under optimised reaction conditions. Although electrocoagulation with aluminium electrodes yielded very limited colour removal and produced a high amount of sludge upon extended reaction time, this application brought about a marked improvement in biodegradability.