A review on the treatment of landfill leachate by coupling advanced oxidation and biological processes

The treatment of landfill leachate requires processes that efficiently remove the different conta-minants present in this type of liquid waste. To treat this type of waste, a great diversity of bio-logical processes has been used, which take advantage of the capacity to transform the different components of the liquid medium into biomass; however, these processes have limitations due to the intrinsic characteristics of the leachate. In recent years, the integration of biological pro-cesses with Advanced Oxidation Processes has been promoted, which would significantly reduce the toxic characteristics of these wastes to comply with the legal conditions to be discharged into the environment without causing damage. In this work, the authors present a review (2015 to 2021) concerning the biological treatment, and Advanced Oxidation Processes (based on ozo-ne, electrochemical processes, and photocatalysis). These processes are analyzed in combination to describe the optimal conditions under which pollutant loads of landfill leachate are reduced. Finally, it is possible to identify that the treatment processes under study are technologies that can be coupled, registering higher efficiencies and lower generation of waste by-products or sludge.