【作者】 潘云霞；

【导师】 郑怀礼；

【作者基本信息】 重庆大学 ， 市政工程， 2008， 博士

【摘要】 垃圾渗滤液是一种危害较大的高浓度有机废水,如不妥善处理,会对周围环境及地下水造成严重污染。但由于垃圾渗滤液的水质水量波动较大,垃圾渗滤液的处理工艺取决于垃圾的组成、垃圾渗滤液中有机物的降解特性以及垃圾的填埋年限和填埋方式等,采用单一的生物、物理化学处理方法都不理想。论文立足于垃圾渗滤液实际处理需要,以节约成本,提高垃圾渗滤液中有机物去除率,加快反应速率为目的,探索垃圾渗滤液处理新工艺。通过厌氧生物处理、吹脱、絮凝和高级氧化组合工艺处理垃圾渗滤液,研究不同工艺对垃圾渗滤液的处理效果,对工艺参数进行优化,分析有机物降解机理,建立动力学模型,并通过毒性生物检测,评价不同工艺处理后的垃圾渗滤液出水对环境的影响。垃圾渗滤液厌氧生物处理方面的研究:比较加入颗粒活性炭和粉末活性炭对垃圾渗滤液中COD、NH₃-N和金属离子的降解效果。结果表明,单独的颗粒活性炭和粉末活性炭对垃圾渗滤液中COD、NH₃-N和重金属的吸附作用不理想。厌氧生物处理中加入活性炭,能促进垃圾渗滤液中有机物的降解,加快垃圾渗滤液的产气速率,提高产气量,增加Fe、Zn、Cu、Cd四种金属元素的去除率;其中,加入颗粒活性炭的反应器,NH3-N、COD和金属元素的去除率最高,产气量也最高。主要原因是在厌氧反应器中加入颗粒活性炭,促进了厌氧颗粒污泥的形成。垃圾渗滤液吹脱及絮凝处理方面的研究:将厌氧生物处理后的垃圾渗滤液,通过吹脱预处理,COD和NH3-N浓度分别下降到2372mg/L和295.7mg/L。再将吹脱预处理的垃圾渗滤液通过絮凝处理,结果表明,硫酸铁、聚合硫酸铁和聚氯化铝铁三种絮凝剂能有效去除垃圾渗滤液的色度、浊度和COD,pH值为5的聚合硫酸铁对垃圾渗滤液的色度、浊度和COD去除效果最好;添加有机高分子阳离子絮凝剂聚丙烯酰胺（CPAM）作助凝剂,能提高垃圾渗滤液的色度、浊度和COD去除率。通过正交实验确定絮凝工艺处理垃圾渗滤液的优化条件是:pH值为5.2,PFS浓度为9.10 mmol/L,反应时间8 min,助凝剂CPAM浓度5 .00mg/L。在此优化实验条件下,垃圾渗滤液的色度去除率为75.6%,浊度去除率为93.6%,COD去除率为56.7%。垃圾渗滤液深度氧化处理方面的研究:将絮凝处理后的垃圾渗滤液分别进行UV/Fenton、US/Fenton和MV/Fenton高级氧化处理,确定这三种高级氧化技术的优化条件,比较他们在优化条件下对垃圾渗滤液COD和色度的去除效果,并对其相关机理进行研究。结果表明,UV/Fenton反应中,当pH值为2.5,Fe²⁺浓度为5 .00mmol/L,H₂O₂浓度为5.70×10² mmol/L时,反应120 min,垃圾渗滤液的色度和COD去除率分别达到最高值99.1%和86.2%;在此条件下的表观动力学方程为:V=-dP/dt=2.6×10^-8×P^1.92×F^1.79×E^1.67。对于US/Fenton反应,当Fe²⁺浓度为5.00 mmol/L,H₂O₂浓度为5.70×10² mmol/L,pH值为2.5,超声功率为100 W,超声频率为45 kHz时,反应90 min,垃圾渗滤液的色度和COD去除率分别达到最高值99.1%和83.4%;其表观动力学方程为:V=lg-（dP/dt）= 1.0×10^-7×P^0.86×F^2.34×E^0.87×H^0.82。对MV/Fenton反应,当Fe²⁺浓度为15.00 mmol/L,H2O2浓度为5.70×10² mmol/L,pH值为2.5,微波功率为800 W时,反应120 s,垃圾渗滤液的色度和COD去除率分别达到最高值99.7%和79.2%;其表观动力学方程为:V=lg-（dP/dt）= 7.0×10^-22×P^0.74×F^0.62×E^2.18×H^2.69。这三种高级氧化处理技术对垃圾渗滤液的色度和COD去除率都高于单独的Fenton反应,而且,日光、超声波、微波三种催化诱导方式都与Fenton试剂存在协同作用。垃圾渗滤液经过这三种高级氧化技术处理后,大分子有机物都被氧化为小分子有机物及二氧化碳和水。三种高级氧化工艺中,UV/Fenton对垃圾渗滤液中的COD去除率最高（86.2%）,但反应所用时间也最长（120 min）,MV/Fenton对垃圾渗滤液中的COD去除率最低（79.2%）,反应所用时间也最短（120 s）;三种氧化处理工艺,不论其降解机理如何,垃圾渗滤液的降解产物都相似,三种处理工艺的降解产物的紫外吸收峰都在210～220nm。垃圾渗滤液急性毒性检测方面的研究:用不同工艺处理后的垃圾渗滤液培养甘蓝种子144 h,观察其种子萌发状况,检测垃圾渗滤液对甘蓝种子萌发的毒性作用。研究结果表明,垃圾渗滤液的浓度越低,对甘蓝种子萌发的毒性也越小,种子萌发率也越高。垃圾渗滤液原液对甘蓝种子萌发的毒性最大,经厌氧生物处理后,毒性有所降低,垃圾渗滤液经絮凝处理后,对甘蓝种子萌发的毒性明显降低。垃圾渗滤液经高级氧化技术处理后,对甘蓝种子萌发的毒害作用虽然降低,但毒害作用依然存在。三种高级氧化技术对垃圾渗滤液毒性的影响差别不大。随着垃圾渗滤液经厌氧生物处理、絮凝和高级氧化处理,垃圾渗滤液的毒性和GT50逐渐降低,EC50逐渐增加。垃圾渗滤液经厌氧生物处理后,再通过吹脱、絮凝和UV/Fenton后续物化处理,垃圾渗滤液的COD浓度由5.05×10⁴ mg/L降低到142 mg/L,达到国家污水三级排放标准,色度和悬浮固体SS达到国家污水一级排放标准（GB18918-2002）。更多还原

【Abstract】 Leachate, as a high concentration organic effluent that seeps from a landfill, will cause severe contamination to the surrounding environment and the groundwater if it is not properly treated. But, due to the greater fluctuations in the quantity and composition of landfill leachate, the treatability of landfill leachate depends on its composition and characteristics, the nature of the organic matter present as well as the age and structure of the landfill. None of the individual biological or physico-chemical techniques is highly effective for the treatment of landfill leachate. Thus, a new effective treatment technology of landfill leachate was explored to improve the removal of organics, accelerate reaction speed and reduce treatment costs. In this dissertation, the treatment efficiencies of different technologies by combining anaerobic biological treatment, stripping, flocculation and advanced oxidation processes were investigated. Various operational parameters affecting the degradation efficiency of landfill leachate were optimized. Meanwhile, for three advanced oxidation processes, the degradation mechanisms of organic matter were analyzed and reaction kinetic model were founded. In addition, the effects of landfill leachate after different treatments on the germination of Brassica oleracea seeds were evaluated by acute toxicity tests.A new combined treatment consisting of anaerobia biological treatment and granular activated carbon （GAC） or powder activated carbon （PAC） adsorption was developed to remove COD、NH3-N and heavy metals from landfill leachate. The results indicated that individual granular activated carbon （GAC） or powder activated carbon （PAC） adsorption has poor performance for the removal of COD、NH3-N and heavy metals. But added activated carbon into anaerobic reactor, the degradation efficiency of organic matter significantly improved, and gas-forming rate and biogas production of landfill leachate evidently increased, and the removal rate of Fe、Zn、Cu and Cd also enhanced. Moreover, in anaerobic reactor of supplied granular activated carbon, Maximal removal rate of COD、NH3-N and heavy metals were achieved, and maximum of biogas production were obtained. This is due to that the supplement of GAC can accelerate the form of anaerobic sludge granulation.After anaerobia biological treatment, ammonium tripping was employed to attain COD concentration of 2372mg/L and NH3-N concentration of 295.7mg/L, respectively. Subsequently, flocculation process was undertaken to remove color、turbidity and COD using ferric sulphate, polyferric sulphate（PFS） and polyaluminium ferric chloride （PAFC）. The results showed that PFS was superior to the other coagulants for the removal of color、turbidity and COD at pH5. The addition of organic macromolecule flocculate polyacrylamide（CPAM） was found to be effective for the removal of color、turbidity and COD. The optimal conditions of flocculation process obtained by orthogonal experiment were 5.2 of pH value, 9.10 mmol/L of PFS and 5.00 mg/L of CPAM at 8 min. 75.6% of color removal rate and 93.6% of turbidity removal rate, as well as 56.7% of COD removal rate were attained in this condition.After flocculation treatment of landfill leachate, Advanced oxidation processes （AOPs）, such as UV/Fenton、US/Fenton or MV/Fenton process, were carried out to attain their optimal conditions. Color and COD removal efficiency of three AOPs were compared, and their degradation mechanisms were further investigated in optimal conditions. The results suggested that 99.1% color and 86.2% COD removal were achieved by using 5.00 mmol/L of Fe²⁺ and 5.70×10² mmol/L of H₂O₂ at pH2.5 in 120 min in UV/Fenton process. Under the optimal conditions, apparent kinetics equation of landfill leachate was V=-dP/dt=2.6×10^-8×P^1.92×F^1.79×E^1.67. For US/Fenton process, the optimal conditions of landfill leachate were ultrasonic frequency of 45 kHz, power input of 100 W, Fe²⁺ concentration of 5.00 mmol/L, H₂O₂ concentration of 5.70×10² mmol/L and pH value of 2.5. Under this condition, maximum color and COD removal of 99.1% and 83.4% were achieved in 90 min, and its apparent kinetics equation was V=lg-（dP/dt）=1.0×10^-7×P0.86×F^2.34×E^0.87×H^0.82. For MV/Fenton process, the optimal conditions of landfill leachate were microwave power input of 800 W, Fe²⁺ concentration of 15.00 mmol/L, H₂O₂ concentration of 5.70×10² mmol/L and pH value of 2.5. Under this condition, maximum color and COD removal of 99.7% and 79.2% were achieved in 120 s, and its apparent kinetics equation was V=lg-（dP/dt）=7.0×10^-22×P^0.74×F^0.62×E^2.18×H^2.69. A comparative study of three AOPs indicated that UV/Fenton, US/Fenton and MV/Fenton attained more color and COD removal rate than Fenton process, and one of three catalytic induced mode, UV、ultrasonic or microwave, has synergistic effect with Fenton reagent. The UV-vis spectrum of landfill leachate reveals that high molecular mass compounds can be oxidized into biodegradable compounds or CO₂ and H₂O after UV/Fenton, US/Fenton or MV/Fenton treatment, and UV-vis absorption peak of degradation product ranges from 210 nm to 220 nm regardless of their different degradation mechanisms. UV/Fenton process achieved maximum COD removal of 86.2% and the longest react time of 120 min, while MV/Fenton process attained minimum COD removal of 79.2% and the shortest react time of 120 s among three AOPs.Brassica oleracea seeds were cultivate with the raw landfill leachate and the effluents produced by different treatment techniques, and their germination percentage were observed in 144 h to determine the acute toxicity parameters EC50 and GT50. The results shows that lower landfill leachate concentration resulted in less toxic to Brassica oleracea seeds and higher germination percentage of Brassica oleracea seeds. The raw landfill leachate was higher toxicity to all seeds tested, but the effluent from anaerobic biological treatment was less toxic than the crude leachate to Brassica oleracea seeds. A greatly reduction in toxicity to Brassica oleracea seeds was observed after flocculation process. However, the toxicity of three post-AOPs effluents was still existed. Three AOPs had little toxic diffience on the germination of Brassica oleracea seeds. Toxicity of Brassica oleracea seeds germination and GT50 values would gradually reduce and EC50 values would gradually increase when landfill leachate were treated by anaerobic biological treatment followed by flocculation and AOPs.After landfill leachate were treated by anaerobic biological treatment followed by trip, flocculation and UV/Fenton process, COD removal rate was degraded from 5.05×10⁴ mg/L to 142 mg/L, and its COD effluents meets third-grade national discharge standard. Furthermore, chroma and SS meet first-grade national discharge standard.更多还原