An Overview of Treatments for Ultraviolet Quenching Substances (UVQS) and Per- and Polyfluoroalkyl Substances (PFAS) Removal from Landfill Leachate

Organics found in landfill leachate (humic acids, fulvic acids, and hydrophilic fraction) have a solid ability to absorb ultraviolet (UV) radiation, which negatively affects UV disinfection; leachate ultraviolet quenching substances (UVQS) can, therefore, have a significant impact on the cotreatment of landfill leachate and sewage in wastewater treatment plants. On the other hand, per- and polyfluoroalkyl substances (PFAS), which pose potential risks to the environment and human health, commonly exist in landfill leachate due to their wide application in various industrial and consumer products. Therefore, removing UVQS and PFAS from landfill leachate is crucial. In this work, the advances in removing UVQS and PFAS from landfill leachate in the last decade are reviewed to find a standard treatment for both contaminants to lower the costs and space required for the leachate treatment process. The benefits and drawbacks of biological, physical, chemical, and electrochemical treatments were examined. Physical, chemical, and electrochemical treatments showed advantages over biological treatments but higher energy and/or material costs. The global analysis indicated that similar technologies, such as adsorption or osmosis, can be used as effective methods to remove UVQS and PFAS from landfill leachate and suggested that both types of pollutants could be eliminated simultaneously with a single treatment based on one of these two technologies.