Performance of Ozone/ZrCl4 Oxidation in Stabilized Landfill Leachate Treatment

Landfill leachate generation is one of the main problems from sanitary landfill. Chemical oxygen demand (COD), ammoniacal nitrogen (NH3-N), and color are among the most problematic parameters in stabilized leachate. In this regard, dedicated treatment facilities are required before leachate can be discharged into the environment. The performance of the combined ozonation (O3) and zirconium tetrachloride (ZrCl4) to treat two types of stabilized leachate was investigated during this study. Leachate samples were collected from an anaerobic stabilized leachate (Alor Pongsu Landfill Site, APLS) and semi-aerobic stabilized leachate (Pulau Burung Landfill Site, PBLS). Zirconium tetrachloride dosage was determined as 1 g/1 g (COD/ZrCl4 ratio) and then added to the leachate samples with 60 min ozonation at natural leachate pH (8). COD, color, and NH3-N were removed from the APLS sample at 33%, 70%, and 53% rates, respectively, whereas 48%, 75%, and 69%, respectively, from the PBLS samples. Ozone consumption was also calculated with the highest value (3.81 Kg O3/ Kg COD) reported in PBLS, whereas the lowest value (2.32 Kg O3/ Kg COD) was reported in APLS. Biodegradability of (BOD5/COD) was investigated and improved from 0.07 to 0.08 for the APLS samples and 0.05 to 0.11 for the PBLS samples after leachate oxidation. Results showed that the performance of O3/ZrCl4 oxidation is more efficient in treating semi-aerobic stabilized leachate than anaerobic stabilized leachate Moreover, the combined method proved to be more efficient in remediating leachate compared with ozone and zirconium treatment alone.