Landfill Leachate Treatment By Advanced Oxidation Technologies

Landfill leachate is a kind of complex organic wastewater and the biologicallytreated effluent hardly reach the national discharged standard. The photo-Fenton,coagulation photo-Fenton, ozone-actived carbon and ultraviolet-ozone were carriedout to treat the effluent which was discharged from biological treatment process. Theoptimum conditions and results were discussed in this article.In the photo-Fenton experiments, the COD removal efficiency goes up then fallsdown when pH and FeSO₄ dosage increases. It goes up to a stable number when H₂O₂dosage increases and goes up with reaction time. Under the optimum conditions, theeffluent COD and chroma were 269mg/L and 652 respectively when the influent CODand chroma were 1112mg/L and 2035.In the coagulation photo-Fenton experiments, the TOC removal efficiency goesup to a stable number when coagulant increases. It goes up then falls down when pH,coagulant aid and stir time increase. Under the optimum conditions, the effluent CODand TOC were 192.17mg/L and 78.99mg/L when the influent COD and TOC were951.55mg/L and 360mg/L respectively.In the actived carbon-ozone experiments, the ozone demand decreases when theactived carbon increases. And the actived carbon's adsorption doesn't vary muchunder various pH value, but the ozone removal efficiency is higher when pH=8. In theozone-actived carbon experiments, the chroma and COD removal efficiency goes upto a stable number when the actived carbon dosage increases after 10min's treatmentby ozone. The effluent chroma and COD were 236 and 204.08 mg/L respectivelywhen the actived carbon dosage was 30g/L. The UV/O₃ method is efficient on the chroma removal, but not on the CODremoval. UV/ozone is not suitable to treat the landfill leachate to some extent.