| Ultrasound has been successfully used to degrade the organic pollutants in wastewater and many water treatment experts pay more attention to study the ultrasonic irradiation technology since the late of 1980's.Ultrasound is an effective way in oxidizing organic contaminants in wastewater either as the independent operation unit or in combination with other treatment methods. In this dissertation the recent studies on the degradation of organic pollutants by ultrasound and associated technologies for the treatment of paper mill wastewater were reviewed. And the researches on the technologies of ultrasonic irradiation,ultrasound/hydrogen-peroxide,ultrasound/ozone and ultrasound/acid-producing white- rot fungi were used to effective degrade paper mill wastewater. The factors, such as ultrasonic frequency,power intensity,dissolved gas,coexistent ion and ?OH radical scavenger affect the efficiency of sonolysis were investigated. The conditions of white-rot fungus producing acid were studied. Meanwhile SPE-GC was used to detect PCP in paper mill mid-wastewater qualitatively. The ultrasonic degradation efficiency and mechanism of PCP were explored. The experimentation showed, as a pre-treatment technology, the processes of ultrasound combine with other technologies are available to treat paper mill wastewater.Results in this dissertation are summarized as follows:(1) Frequency is an important parameter of the ultrasound and it has a strong affect on the ultrasonic degradation effect of organic pollutants. As to the basic black liquor, the productivity of ?OH and degradation efficiency increas with the increases of ultrasound frequency. When the ultrasound was used alone, the productivity of ?OH is 1.68μmol l-1min-1 with a frequency of 1040KHz and are 0.73μmol l-1min-1 and 0.94μmol l-1min-1 with frequencies of 20KHz(80W) and 40KHz(100W) respectively. (2) Acoustic power or acoustic intensity is also an important factor of the ultrasound. There is an optimal acoustic intensity to degrade the organic pollutants based on the consideration of the technology and the economic effect. In this study the optimal power intensity of the 20KHz reactor and 40KHz reactor are 80W, 100W respectively.(3) Aerating gas to the black liquor increase the effect of ultrasonic cavitation, the order of degradation rate of different saturated gas is as follow: O2>Air>N2>degassed. Adding appropriate quantity of NaCl and TiO2 catalyst increase the degradation efficiency of black liquor.(4) The ultrasonic degradation of black liquor mainly undergoes preferential hydroxyl radicals oxidation out of the cavitation bubble either in the limit layer or in the bulk solution. Addition of 2.0 mmol l-1 C4H9OH restrains the ultrasonic degradation of black liquor.(5) Compares with the ultrasonic irradiation alone, the combination of ultrasonic irradiation with H2O2 oxidation can increase the degradation effect of black liquor. The optimal efficiency is achieved at the concentration of 2‰H2O2. US/H2O2 process shows the synergetic effect when acidifying filtrate of black liquor was treated, and US/Fenton process further increases the degradation effect. The COD removal is 47.9% and the TOC removal is 45.8% after 4hr treatment.(6) Compares with the ultrasonic irradiation alone, the COD removal ratio increases about 20% by the process of US/Ozone after 1hr treatment. At the condition of 40KHz and 100W, the decomposition of Ozone appears to follow pseudo first-order kinetic and the decomposition constant of ozone is 13.6 times than the constant without ultrasound; the dissolution constant of ozone is 1.7 times than the constant without ultrasound.(7) SPE-GC was used to detect PCP in paper mill mid-wastewater qualitatively, the ultrasonic degradation of PCP also mainly undergoes preferential hydroxyl radicals oxidation. Initial pH and concentration are the main factors effect on the ultrasonic degradation of PCP. The degradation of PCP follows to pseudo first-order kinetic and the reactive rate constant is 0.0978hr –1.(8) Aci...
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