Improved Pretreatment (Coagulation-Floatation and Ozonation) of Younger Landfill Leachate by Microbubbles

A novel microbubble air/ozone floatation device, TCRI, was developed to enhance the combination of the coagulation and ozonation processes as the pretreatment of landfill leachate. In the coagulation process, microbubble floatation reduced the coagulant dosage. The removal efficiencies of chemical oxygen demand (COD), color, nitrate, and ammonia for the coagulation microbubble floatation were 97, 20, 47, and 163% higher, respectively, than those of the coagulation-sedimentation process; in the ozonation process, the removal efficiencies of ammonia and COD in microbubble ozonation were increased by 300 and 200%, respectively, compared with a conventional ozonation contactor when the ozonation time was 60 minutes. The results showed that microbubbles could reach a higher ozone-transfer rate (microbubbles - 0.3018 min(-1) > conventional ozone bubbles = 0.2014 min(-1)). Therefore, the application of the microbubble technology in the coagulation and ozonation combination process may provide an effective and low-cost approach for wastewater treatment. Water Environ. Res., 82, 657 (2010).