Landfill leachate is one of the most important pollution sources for groundwater. Refractory organics and ammonia are two major pollutants of environmental concerns in landfill leachate. Despite a common leachate treatment option in the U.S., publicly owned treatment works (POTW) are not feasible in many cases for various reasons, and cannot truly eliminate the persistent species. In this study, we evaluated the performance of thermally activated persulfate (TPA) oxidation for simultaneous removal of chemical oxygen demand (COD) and ammonia from a mature landfill leachate. The pollutants were oxidized primarily because of sulfate radicals (a strong oxidizing agent) that were produced from persulfate catalysis by heat, and partially due to persulfate itself. Different factors influenced the treatment efficiency to different degrees. COD removal peaked at pH 3.0 and 4.0, and then was decreased with the pH increase from 4.0 to 8.3 (the original pH). A high alkalinity in the leachate likely scavenged free sulfate radicals at pH above 4.5, though more sulfate radicals were produced at a high pH. Temperature from 27-50oC and persulfate dose (defined as the normality ratio of persulfate to initial COD in this study) at 0.1 - 2.0 were studied. High temperature and high persulfate dose typically led to a high COD removal. The maximum COD removal of 89% was achieved at 50oC and persulfate dose = 2.0. Meanwhile, 100% of 2,000 mg/L ammonia nitrogen was removed. Our results demonstrated that TPA is a promising on-site landfill leachate management method, as well as an effective chemical oxidation for remediating the groundwater contaminated by landfill leachate.

Thermally activated persulfate (TAP) oxidation for simultaneous removal of refractory organics and ammonia in mature landfill leachate

241st National Meeting (2011)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.