Treatment of Textile Wastewater Using a Combined Coagulation and DAF Processes, Iran, 2016

Background & Aims of the Study: There are three different types of fibers used in themanufacture of various textile products: cellulose fibers, protein fibers and synthetic fibers.Textile wastewater discharge into the environment leads to irreparable damages. The mainpurpose of this study was treatment of textile wastewater, using a combined coagulation anddissolved air flotation (DAF) processes, Iran in 2016.Materials and Methods: This study was an empirical-lab study which the Jar tests and DAFwere used in laboratory scale. After determination of the optimal condition of pH and theoptimum of concentration of poly-aluminum chloride by Jar test, the effect of the effectiveparameters including the concentration of the coagulant (10, 20, 30, 40, 60 mg/L), coagulationtime (5, 10, 15 and 20 min), flotation time (5, 10, 15 and 20 sec), saturation pressure ( 3, 3.5, 4and 4,5 atm) and turbidity ( 10, 20 , 30, 40, 60 NTU) on the removal efficiency of COD, BOD5and TSS by DAF were studied.Results: Results of this study showed that the DAF process can treatment COD, BOD5 and TSSup to85.7%, 80.68% and 95.6%, respectively. The appropriate condition was as follows: pH=6,initial concentration of aniline= 200 mg/L, flocculation time = 10 min, flotation time= 20 sec andthe air pressure= 4 atm. Also, this study indicates that the DAF process to conclusion requires alower dosage of poly-aluminum chloride.Conclusion: The coagulation and DAF processes can be effective to treat textile wastewaterfrom industries.