Abstract:
The objective of this study was to find the relationship between foam stability and froth flotation efficiency in oily wastewater treatment. Sodium dodecylbenzenesulfonate (SDBS) and the Novous CE 2680 were used as the surfactant and flocculant, respectively.The first part of this work was to investigate the operational parameters affecting foam stability by using batch flotation columns. The columns were made of PVC pipes with four different diameters: 4, 8, 12 and 20 in. The results showed that the foam height was significantly affected with the air flux. The concentration of surfactant added also affected positively the foam height. However, the column diameter in the studied range did not affect the foam height. The second part was to determine froth flotation efficiency in treating oily wastewater treatment using a continuous froth flotation unit. The column made of glass had 10 and 140 cm in diameter and height, respectively. The synthetic wastewater used in this experiment had 50 mg/l of lubricant oil (PTT Performa) and it was constantly stirred. From the experimental results, it was found that the oil removal reached 90 percent efficiency at the critical micelle concentration of surfactant and 250 mg/l of a cationic polyelectrolyte. The addition of the polyelectrolyte gave much higher efficiency of oil removal than using only the surfactant, which only had 6.9 percent of oil removal efficiency. And when reducing a surfactant concentration to 0.5 CMC, the oil removal efficiency decreased to 77.5 percent.