Advanced oxidation processes for treating raw leachate: an experimental study (Barka landfill, Oman)

Management of municipal solid waste leachate has become an urgent environmental problem in many countries due to the high growth of population and consumption trends. Advanced oxidation processes (AOPs) are efficient methods to treat leachate because of their high ability to reduce unpleasant parameters. Although the simultaneous application of different AOP methods is more effective than a single process, the simultaneous application of AOPs for the treatment of municipal solid waste leachate has received little attention. To fill this knowledge gap, this study presents the simultaneous application of AOP methods to treat municipal solid waste leachate. The efficiency of AOPs was studied in terms of organic compounds such as chemical oxygen demand (COD) and total organic carbon (TOC). Leachate samples were collected from the Barka landfill, which is located in the north-east of Oman. Four combinations of applied AOP methods (e.g. ozone (O₃), hydrogen peroxide (H₂O₂) and ultraviolet (UV)) in this study resulted in the order of hydrogen peroxide/ozone/UV > hydrogen peroxide/ozone > ozone/UV > hydrogen peroxide/UV according to the COD removal efficiency. Combining these AOP methods resulted in an about 1.5 times increase in COD removal (56.62%) and a 1.9 times increase in TOC removal (39.34%) compared with the individual applications.