Enhancing Purification of Surface Water by Potassium Permanganate Addition

The aim of the present research is studying the effect of potassium permanganate addition on the pre-oxidation and coagulation of the surface water. River Nile and El Rayah El Tawfeky of Benha city, Egypt were the surface water supply used in this research. The results showed that El Rayah El Tawfeky raw water had higher turbidity concentration and humic acids absorbance (8.5 NTU and 0.024, respectively) than that of River Nile (6.5 NTU and 0.018, respectively). The optimum dose of potassium permanganate ranged between 4 and 6 mg/L for coagulation process, while for oxidation of humic acid, at higher dose of potassium permanganate a higher removal can be achieved. At a constant dose of potassium permanganate (6 mg/L), the optimum dose of alum ranged between 40 60 mg/L and it was 85 105 mg/L for ferric sulfate. Addition of potassium permanganate (6 mg/L) to the raw water of El Rayah El Tawfeky and River Nile without using of any coagulant resulted in a turbidity removal of about 35%. Therefore, potassium permanganate addition led to a significant turbidity removal. At alum dose of 40 mg/L and potassium permanganate dose of 6 mg/L, the turbidity and humic acid removal were 70 and 75%, respectively, for the raw water of El Rayah El Tawfeky and were 58 and 44%, respectively, for the raw water of River Nile. At ferric sulfate dose of 85 mg/L and potassium permanganate dose of 6 mg/L, the turbidity and humic acid removal were 53 and 50%, respectively, for the raw water of El Rayah El Tawfeky and were 20 and 17%, respectively, for the raw water of River Nile. Therefore, the alum had better results than the ferric sulfate. The optimum pH was 6.0 8.5, which is similar to that of raw water of El Rayah El Tawfeky and River Nile, i.e. no need for pH adjustment.