The Study Of Landfill Leachate Treatment By Gamma Irradiation

Landfill leachate was a kind of organic wastewater, producing in the process of landfill whichcontains many environment pollutants. Due to its complex and changefully composition, itstreatment has been a worldwide problem. Ionization irradiation technology is an advanced oxidationtechnique which is based on hydroxyl radical. More and more attention were paid to it because it canperform a rapid and efficient, without the addition of chemical reagents and does not producesecondary pollution. Currently，it has been widely used in the degradation of environmentalpollutants and wastewater treatment.In this paper, the landfill leachate was irradiated by gamma ray from60Co. The effects ofirradiation dose and initial pH value of leachate on radiation degradation efficiency were studied. Inaddition, the synergistic effects between gamma irradiation and H₂O₂on irradiation degradationefficiency were also studied. Moreover, as a model substances, the commercial humic acid was usedto study the effect of gamma irradiation on refractory compositions in landfill leachate. The researchresults show:（1）The gamma irradiation can’t effectively removal the pollutants in landfill leachatewithout any pre-treatment. However, the initial pH plays an important role on the gammadegradation. When the initial pH was3, irradiation dose was40kGy, the removal of CODcr, BOD5and turbidity was up to40%,51%and80%respectively. Meanwhile, the landfill leachate remainedhigh biodegradability after gamma irradiation when pH was3.（2）The effect of irradiation treatment of landfill leachate was improved obviously by anaddition of H₂O₂. When the initial pH was3, the concentration of H₂O₂was10mmol/L andirradiation dose was40kGy, the removal of CODcrand turbidity was up to44.3%and98.3%,respectively. It was considered that the concentration of H₂O₂and initial pH is vital in the processingof landfill leachate treatment by γ/H₂O₂.（3）The gamma irradiation can be effective to degradation of the refractory compositions inlandfill leachate. When the irradiation dose was40kGy and the initial concentration of HA solutionswas0.12g/L, the CODcrremoval was60%.In conclusion, under certain conditions, gamma irradiation can effectively remove pollutantsin landfill leachate. Therefore, it is feasible that the gamma irradiation was applied in landfillleachate treatment.