Photocatalytic Treatment of Oily Wastewater

Abstract

Oily wastewater is among the most difficult to treat in conventional treatment plants. It is produced in increasing quantities in recent years, which can lead to serious environmental and population health problems if not treated properly. Recently, it was found that treating oily water through the photocatalytic process is a safe and highly efficient method. The present study is concerned with the treatment of the effluents of edible oils plants through the photocatalytic process, using corn oil, sunflower oil, and using titanium dioxide as a catalyst. The most important elements affecting the photocatalytic process were studied, such as the initial concentration of the oil, the concentration of the catalyst, and the number of revolutions per minute of the pump used. The two types of oils were also mixed in different proportions, and the effect of the aforementioned elements was studied. The most important conclusions obtained were as follows. When studying single oil emulsion (corn oil/water emulsion), it was found that increasing the initial concentration reduces the degradation rate. Three initial concentrations of the oil were studied 1000, 2000, and 3000 mg/L. The percentage degradation for these initial concentrations was 92.7, 92.6, and 79.41, respectively. The trend for the number of revolutions per minute (r.p.m) are opposite to this, i.e., increasing rpm leads to an increase in the degradation rate. When mixing oils at a ratio of 50/50, it is found that increasing the number of (r.p.m) leads to a decrease in the degradation rate, while mixing the two oils at a ratio of 75/25, corn oil/sunflower oil, the results are reversed and the oil mix behaves the same way as a single corn oil/water mix. In contrast, it is found that by increasing the initial concentration or the catalyst in the oil mixture, the degradation rate increases. Thus, it is concluded that mixing the effluents of oil wastes has a retardation effect on its degradation.