The objective of this research was to study the color and organic removal efficiency using Advance Oxidation Processes (AOPs) and Co-substrate on landfill leachate treatment by UASB with acid tank. There were three phases of experiments. The first phase of experiments was studying a role of co-substrate on the anaerobic treatment of landfill leachate. There were 3 experimental sets in this study. The co-substrate in each experimental set were cane sugar and soy milk. The ratio of leachate COD: Co-substrate COD were varied to 1:0 (controlling set), 1:1, 1:2 and 1:4. The diluted leachate COD was about 1000 mg/l and HRT was kept to be 2 days. From experiments, it was found that using cane sugar as co-substrate with ratio of leachate : sugar = 1:1 gave the best result. When compare the result with controlling set the color removal and the COD removal were 15% and 17% respectively. The second phase was studying AOPs on leachate treatment. The AOPs choosed to study were O₃, O₃/H₂O₂ and Fenton's reaction. O₃ dosage were varied to 100, 200 and 400 mg/l-hour. O₃/H₂O₂ ratio were varied to 2:1, 1:1 and 1:2 by mole. Fenton's reaction varied H₂O₂ dosage from 500 to 2000 mg/l. H₂O₂:Fe²⁺ varied to 2:1, 5:1, 10:1, 20:1 and 30:1. From experiment the Fenton's reaction could remove 90% of color and 76% of COD when used H₂O₂ dosage 2000 mg/l, H₂O₂:Fe²⁺ = 10:1 and 30 minutes for reaction time. In case of using O₃ and O₃/H₂O₂, its could remove color about 85-94% but could remove COD about 27-35% only. The last phase was studying the color and COD removal efficiency of using Fenton's reaction and co-substrate on leachate treatment. According to phase 1 and 2, the Fenton's reaction used H₂O₂ dosage 2000 mg/l, H₂O₂:Fe²⁺ = 10:1, reaction time 30 minutes and the ratio of leachate per cane sugar equal 1:1, from the experiment it was found that using Fenton's reaction followed by UASB provided the best result. This method could remove COD 85% and remove color 90%. While Adding co-substrate did not improve the decolorization efficiency and COD removal.
