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研究报告

Decomposition of organic pollutants in rural waste transfer station leachate using ozone system

基金项目：农业部农村可再生能源开发利用重点实验室开放研究课题（No.201612）；中国农业科学院科技创新工程；四川省科技创新苗子工程项目（No.2015038，2015039）

摘要：村镇垃圾中转站渗滤液具有量小、分散、污染性强等特点.为控制其有机污染，本研究采用操作灵活、高效的臭氧法处理该渗滤液，考察了反应时间、臭氧投量、初始pH值、反应温度、双氧水投量对渗滤液中有机污染物降解的影响.结果表明：当反应时间为20 min、臭氧投量为1.24 g·h^-1、初始pH值为7.00、反应温度为25℃时，渗滤液色度（CN）和COD_Cr的去除率分别达83.57%、61.53%；在上述条件下，额外向反应体系中投入1 mL·L^-1双氧水后，其色度、COD_Cr去除率分别提高了4.88%、14.23%.由于村镇渗滤液中大分子有机物的降解，反应60 min后BOD₅/COD_Cr值从0.24提高到0.56，且由于矿化作用，HCO₃^-浓度增加了1297.89 mg·L^-1.此外，紫外-可见光谱显示，臭氧能明显降低渗滤液的芳香性程度和腐殖化程度；三维荧光光谱表明，臭氧能快速氧化渗滤液中结构较为稳定的类富里酸，极大程度地降低渗滤液中有机污染物的分子缩合度和分子量.经估算，反应过程中药剂成本约7.37元·m^-3.

Abstract：Leachate of rural waste transfer station is featured with small quantity, wide decentralization and severe pollution. To control its organic pollution, leachate was treated with easy-to-handle and efficient ozone system in this study. Five influencing factors including reaction time, ozone dosage, initial pH value, reaction temperature and H₂O₂ dosage were investigated. At 20 min of reaction time, 1.24 g·h^-1 of ozone, 7.00 of initial pH and 25℃, the removal efficiencies of color CN and COD_Cr achieved 83.57% and 61.53%, respectively. In contrast, the removal efficiencies were improved by 4.88% and 14.23% by the addition of 1 mL·L^-1 H₂O₂ to the reaction system. After ozonation, the ratio of BOD₅/COD_Cr was increased from 0.24 to 0.56, because of decomposition of the refractory organics. Moreover, the concentration of HCO₃^- was increased by about 1297.89 mg·L^-1, due to mineralization of the organics. UV-Vis spectra analysis indicated that the aromatic matters and humic of the leachate were greatly deceased by ozone. Results of 3D-EEM spectra analysis showed that ozone could quickly oxidize the structurally stable fluvic acid-like organic matter in the leachate. And the molecular condensation degree and molecular weight were reduced significantly. In estimation, the dosage cost was about 7.37 yuan·m^-3.