【作者】 李丹丹；

【导师】 郑怀礼； 谭铭卓；

【作者基本信息】 重庆大学 ， 环境科学， 2008， 硕士

【摘要】 垃圾渗滤液经生物处理后仍难达标排放,因此本研究选用混凝与Fenton联用对经厌氧生物处理后的垃圾渗滤液进行深度处理,以期得到较好的处理效果。垃圾渗滤液先经吹脱处理,COD和NH₃-N浓度分别下降到2.37×10³mg/L和295.7mg/L。混凝试验结果表明,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和COD,pH值为5的聚合硫酸铁对垃圾渗滤液的色度和COD去除效果最好;投加有机高分子阳离子絮凝剂聚丙烯酰胺作助凝剂,能提高垃圾渗滤液的色度和COD去除率。通过正交试验确定优化条件:pH值为5.2,聚合硫酸铁浓度为9.1 mmol/L,反应时间8 min,助凝剂浓度5 mg/L。此时垃圾渗滤液的色度去除率为75.6%,COD去除率为56.7%。将混凝处理后的垃圾渗滤液再分别进行光助芬顿（Photo/Fenton）、超声波协助芬顿（US/Fenton）氧化处理,确定优化条件,比较两者在各自优化反应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,Photo/Fenton反应中,当pH值为2.5,Fe²⁺浓度为5 mmol/L,H₂O₂浓度为570 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 mmol/L,H₂O₂浓度为570 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=-dP/dt= 1.0×10^-7×P^0.86×F^2.34×E^0.87×H^0.82。可以看出,两种方法对垃圾渗滤液色度和COD去除率都高于单独的Fenton反应,日光、超声波的催化诱导方式与Fenton试剂存在协同作用。其中,Photo/Fenton对垃圾渗滤液中的COD去除率最高,但反应时间最长;US/Fenton对垃圾渗滤液中的COD去除率较低,但反应时间较短;两者方法处理后的降解产物的紫外吸收峰都在210²20 nm。垃圾渗滤液经过这两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。更多还原

【Abstract】 Landfill leachate was still difficult to satisfy the requirements of environmental protection standard about discharging after biological treatments. Thus, an effective treatment technology combined Coagulation-flocculation and different Fenton oxidation method of landfill leachate was investigated to emprove the treatment efficiencies. After anaerobia biological treatment, ammonium tripping was employed to attain COD concentration of 2.37×10³ mg/L and NH3-N concentration of 295.7 mg/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 5 of pH value. 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, 9.1mmol/L of PFS and 5 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, Photo/Fenton and US/Fenton process, were carried out to attain their optimal conditions. Color and COD removal efficiency of them 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 mmol/L of Fe²⁺ and 570 mmol/L of H₂O₂ at pH 2.5 in 120 min in Photo/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 mmol/L, H₂O₂ concentration of 570 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=-dP/dt= 1.0×10-⁷×P^0.86×F^2.34×E^0.87×H^0.82. A comparative study of them indicated that Photo/Fenton and US/Fenton attained more color and COD removal rate than Fenton process, and photo、ultrasonic has synergistic effect with Fenton reagent. Photo/Fenton process achieved maximum COD removal and the longest react time, while US/Fenton process attained minimum COD removal and the shortest react time.The UV-vis spectrum of landfill leachate reveals that UV-vis absorption peak of degradation product ranges from 210 nm to 220 nm regardless of their different degradation mechanisms, and high molecular mass compounds can be oxidized into biodegradable compounds or CO₂ and H₂O after Photo/Fenton and US/Fenton treatment.更多还原