EVALUATION OF INDUSTRIAL DYEING WASTEWATER TREATMENT WITH COAGULANTS AND POLYELECTROLYTE AS A COAGULANT AID

Textile industry is the major source of water consumption and wastewater pollution. There are various treatment techniques to remove textile wastewater pollution. Coagulation-flocculation is a widely used process to remove pollution due to suspended particles. In this research, different coagulants like Alum, Lime, FeCl3, FeSO4 and MgCl2 were applied to select the suitable ones with optimum removal efficiency. Settling characteristics of flocs formed in the coagulation process were studied in a laboratory scale settling column unit. Parameters such as color, COD, TSS, turbidity and settled sludge volume have been evaluated. The optimum coagulant dose and pH value were determined by comparing the effectiveness of these coagulants. Results showed other coagulants except lime could eliminate color and COD successfully. In this case, FeSO4 was chosen as an optimum coagulant for color removal because of the lowest required coagulant dose, minimum settled sludge volume and maximum decolorization.