Application of Anaerobic and Ozonation Processes in the Landfill Leachate Treatment

The optimization of leachate treatment was investigated as well as the configuration of a biological-ozonation process. The leachate used for the experiments was diluted to 1/5 with tap water and treated anaerobically. The anaerobic effluent and the raw leachate were treated with ozone in order to increase their biodegradability getting the minimum organic matter removal. Both were submitted to the ozonation process, applying a constant ozone dose and varying the contact time. The ozonation of raw leachate produced a decrease of COD and BOD₅ concentrations as well as BOD₅/COD ratios, applying an ozone dose of 38.72 mg/L·min and contact times between 15 and 60 minutes. Ozonation as a pre-treatment process to the biological system did not improve the biodegradability of the raw leachate. The anaerobic effluent from the reactor fed with leachate diluted to 1/5, was subjected to an ozone dose of 34.99 mg/L·min and applying different contact times. BOD_f values increased from 74.75 up to 1220 mg/L and BOD_f/COD ratios reached values higher than 1. Then, the application of ozone to the anaerobic effluent led to the improvement of the biodegradability of the leachate as well as the BOD_f/COD ratio for all the contact times used.