Improvement of the Effluent Quality for Re-use in Dyeing Industry

Abstract

Treatability of the effluent from the activated sludge process in dyeing industry for re-use was investigated.The methods consist of the color removal by Fenton’s reagent followed by oxidation with potassium permanganatefor the iron removal, the remained contaminants were reduced by activated carbon and ion exchange ormembrane processes. It was found that the optimum pH of 4.0, ferroussulfate and hydrogenperoxide at concentrationof 100 and 27.5 mg/l respectively were suitable for Fenton’s reagent with the color removal efficiency of 92.66%. After this process, the iron concentration in treated water was increased so potassium permanganate were usedto get rid of iron with a KMnO₄ /Fe mole ratio of 1:1 and varied pH in the range of 8.0 - 10.0. The resultsshowed that the optimum pH was 9.5 with the iron removal efficiency of 98.28 %. the treated water weresuitable to use for toilets, lawn sprinklers, cleaning floor and once through cooling water. The results of studyby the activated carbon, the total hardness and calcium were reduced from 83.04 and 68.51 mg/l as CaCO₃to 2.08 and 0 mg/l as CaCO₃, respectively but the pH value was increased to 9.45 so the treated water wasneutralized with H₂SO₄ solution and feeded through ion exchange or membrane process to improve thequalities of water in order to use in the processes, cooling tower and boiler.