【作者】 陶美君；

【导师】 黄卫红；

【作者基本信息】 华中科技大学 ， 环境科学， 2005， 硕士

【摘要】 超声辐照技术是近几十年来发展迅速并广泛研究应用的一项水处理技术。利用超声辐照技术来处理水中难降解有机污染物的研究已经引起了国内外水处理专家的广泛关注。本文首先介绍了近几十年来利用超声波降解水中难降解有机污染物的研究进展及其降解机理。以含有高浓度NH_3-N的垃圾渗滤液为处理对象,研究了混凝及超声技术处理垃圾渗滤液的工艺条件,分别探讨了混凝剂种类、pH值、混凝剂投药量、沉降时间、超声频率、电功率、超声时间、声反应器类型、氨氮的初始浓度、曝气等主要因素对含有高NH_3-N浓度的垃圾渗滤液处理效果的影响。1.混凝预处理垃圾渗滤液的研究主要结论如下: （1）铁盐对垃圾渗滤液的絮凝效果均比铝盐好; 在本文的研究条件下以聚合硫酸铁作为絮凝剂; PFS最佳投药量控制在2.4g/L; 溶液的最佳pH值范围为5.0～7.0; 沉降时间达到25min后,COD和色度的去除率随时间变化不大; （2）混凝最佳工艺参数下,CODcr、SS、色度均有下降。但是NH_3-N几乎没有去除。加入助凝剂PAM对提高COD去除率不明显。2.超声处理经过混凝预处理后的渗滤液的主要研究结论如下: （1）随着废水初始pH值的升高,NH_3-的去除率上升; 本实验将废水的最佳初始pH值控制在11左右。（2）超声发生器的声功率和声强对NH_3-N的去除及有机物的降解效果都有明显的影响。NH_3-N的去除率随着电功率的提高而升高; 而对于垃圾渗滤液这种特定反应体系中的有机污染物降解而言,存在一个最佳电功率。20KHz条件下,声功率200W时超声空化效应强于100W和60W; 而在40KHz的条件下,声功率80W的超声空化效应优于100W和60W;更多还原

【Abstract】 Ultrasound has been successfully used in wastewater treatment and many environmental scientists pay more attention to the application and study at the ultrasonic degradation techniques. In this dissertation the recent research on the degradation of organic pollutants by ultrasound and associated technologies for the treatment of paper mill wastewater were reviewed. The flocculation and the ultrasonic irradiation techniques were used to degrade landfill leachate. The influence of the operation parameters on the efficiency of degradation were investigated, such as flocculation kind, pH, the amount of drug, sedimentation time, ultrasonic frequency, power intensity, duration time, ultrasonic reactor, different NH^3-N and aeration stripping. 1. Results of flocculation degradation of landfill leachate are summarized as follows: （1） The flocculation efficiency at landfill leachate by using containing Fe-salt is better than that by Al-salt. In the study, a best result could be achieved by using 2.4g/L PFS as flocculation. At the pH of 6.0, the decrease rate of COD and chromaticty did not change after 25 minutes of treatment. （2） Under the optimum condition, CODcr、SS and chromaticty all decreases, but NH^3-N did not. It is not helpful to the removal of COD by adding PAM. 2. After flocculated, ultrasonic degradation techniques were applied in the landfill leachate. Several results were obtained: （1） With the increasing of pH of the waste water, the removal of NH^3-N was to rised; In thi study, the landfill leachate were adjusted to pH of 11 before ultrasonic degradation. （2） The power and intensity of the ultrasound obviously affect on the removal of NH^3-N and the degradation effectiveness of the organic pollutants. The removal of NH^3-N rised with the increaseing of the power. But for landfill leachate, there is an optimal power at a certain intensity. In this study, the optimal power when frequency is 20KHz and 40KHz is 200W and 80W, respectively. （3） In this study: with the same type of ultrasonic reactor and the same acoustic power, the use of intensity of 20KHz is more efficient for the removal of NH3-N and degradation of organic pollutants than of 40KHz. （4） The ultrasonic degradation is a very simple and affective method for the treatment of landfill leachate with high concentration of ammonia nitrogen. After 3hr of ultrasonic treatment, the concentration of ammonia nitrogen was decreased from 1643mg/L to 225mg/L, a removal of NH3-N of more than 86 percent was achieved. （5） To combine with ultrasonic degradation technique, the time when combination technique applied could be significant shorten, as well as the efficience of aeration technique increased. After applying the combination technique for 1.5 hours, the removal of NH3-N is almost the same as that by just using ultrasonic treatment alone for 3 hours. The combination technique can also increase the degradation of organic pollutants in landfill leachate than that by just using ultrasonic method. （6） The mechanism study of the ultrasonice degradation shows that aeration purge plays a key role in the removal of NH3-N in landfill leachate. （7） Addition of 0.15mg/L n-C4H9OH in the landfill leachate, the organic compounds could not be degraded. This shows that the hydroxyl radical oxidation plays a key role in the degradation of organic compounds, because the C4H9OH destroys the hydroryl radicals.更多还原