Abstract:
To evaluate the efficiency of treatment of COD in wastewater from the textile industry by oxidation and coagulation. The experiment was carried out in 2 individual steps, the coagulation and the oxidation. The coagulation was carried out by using 4 coagulants : PAC, Alum, Ferous sulphate and Lime. The oxidation step was carried out by using Aeration and 3 oxidizing agents : Hydrogen peroxide, NaOCl and potassium permananate. The studied variables were pH, time and amount of coagulants and oxidizing agents. In the coagulation step, the COD removal efficiency of PAC, Alum, Ferous sulphate and Lime were in the range of 57.13-94.62%, 66.91-86.47%, 6.19-44.50% and 14.75-35.94% respectively. The optimum conditions for coagulation used PAC 1,000 mg/L at pH 6 for which the COD removal efficiency was 94.62%. In the oxidation step, the range of time for aeration after coagulation was not effected by the COD removal efficiency. The COD removal efficiency of Hydrogen peroxide, NaOCl and potassium permananate were in the range of 46.4-84.07%, 65.81-89.51% and 65.42-80.19% respectively. The optimum conditions for oxidation used NaOCl 1,000 mg/L for which the COD removal efficiency was 89.51%. The optimum conditions for treatment of COD in wastewater from the textile industry used PAC 1,000 mg/L and NaOCl 1,000 mg/L at pH 6.