Ferrous ion-activated persulphate process for landfill leachate treatment: removal of organic load, phenolic micropollutants and nitrogen

The innovative S2O82-/Fe2+ treatment technology based on sulphate radicals induced oxidation was applied for the treatment of landfill leachate. The performance of chemical oxygen demand (COD) and dissolved organic carbon (DOC) removal in the Fe2+-activated persulphate system was moderate; however, the results of dissolved nitrogen (DN) and total phenols removal showed significant efficacy (<= 39% and >= 87%, respectively). S2O32- addition to the S2O82-/Fe2+ system enhanced the treatment efficacy and resulted in supplementary 15% of COD and 5% of DN removal. Hydroxyl radical-based H2O2/Fe2+ treatment of the landfill leachate was performed as well; the results indicated higher removal efficacy of COD and DOC compared to the S2O82-/Fe2+ system. However, practical application of the H2O2/Fe2+ system is considerably influenced by temperature rise and excessive foam formation. Generally, the ferrous ion-activated persulphate treatment could be a promising technology for ex situ as well as in situ landfill leachate treatment applications.