Advanced oxidation processes for treatment of industrial wastewater

Abstract

Due to the increased pollution of waters, the general interest is to put this issue in the foreground, as one of the biggest problems of modern society. Following that, there is a need for the development of various technologies for their purification, as well as their constant improvement from the point of cost-efficiency of the process. Because of that, various techniques called ‘’advanced oxidation processes’’ are applied to remove pollutants from wastewater. They differ in the mode of action and application in specific cases of water pollution (i.e., the origin and type of treated wastewater). The following techniques are most commonly used: ozonation, ultrasound (US), UV radiation, and different combinations of them: ozonation with US, UV radiation with various catalysts, ozone with hydroxide-peroxide, etc. Before the advanced processes, the application of standard wastewater treatments (such as coagulation, flocculation, sedimentation, and filtration) was performed to optimize the applied treatment, as well as to assess the increase the overall efficiency of so-called ‘’coupled technologies’’. In this study, the wastewater samples originating from the armor industry were treated firstly by coagulation, and then with a combination of ozone and US. The purification efficiency was analyzed by reducing the concentration of heavy metals (Pb2+, Cd2+) using atomic absorption spectroscopy (AAS). The concentration of organic pollutants was followed by the values of chemical oxygen demand (COD) and biochemical oxygen demand (BOD5). The removal degree of metals were over 70%, and organic compounds were 95%). Based on the obtained results, combining the conventional and advanced wastewater treatment, the optimal purification solution was determined.