| In recent years, due to the rapid development of the electronics industry, the demand for printed circuit board (PCB) is increasing. The high concentration organic wastewater discharged from PCB is also increasing. The organic wastewater of PCB is a kind of high concentration COD organic wastewater which hard to biodegradation and complex composition. Once it is discharged into environment by improper handling, it would caused serious pollution. Ultrasonic irradiation is one of advanced oxidation wastewater treatment technology which can pyrolysis. It can process wastewater with other technology easily. This study is to apply ultrasound to deal with the PCB organic wastewater. Three part of the work were done. First, the simulated wastewater containing hydroquinone and benzotriazole were removed by ultrasonic; Second, the process parameters were studied in the part of the ultrasonic treatment with chemical for dealing with PCB organic wastewater; Third, the treatment equipment was invented and was applied to the treatment of PCB organic wastewater in the PCB wastewater treatment plant.The simulated wastewater containing hydroquinone, benzotriazole respectively were investigated using ultrasonic irradiation. The results showed that the ultrasonic degradation of the simulated wastewater containing hydroquinone, benzotriazole respectively have certain effects. Under the condition of ultrasonic time 60min, the degradation rate of the simulated wastewater containing hydroquinone was 97% by ultrasonic treatment; the study of the degradation of the simulated wastewater containing benzotriazole (BTA) was also shown that the BTA had been removed in the simulated wastewater after ultrasound 120min. The rates of sonolysis degradation of the two substances promotes when the ultrasonic power is enhanced, the pH value decreases. However, the ultrasonic frequency exists an optimum value for the rates of the two substances. The degradation of hydroquinone, BTA by ultrasonic treatment were predominantly eliminated by means of OH·oxidation. And the sonodegradations of hydroquinone, BTA were found to follow a pseudo-first-order kinetic model. The range analysis of orthogonal experiment showed that the influence degrees of ultrasonic factors on the degradation rate of benzotriazole by ultrasonic degradation in ascending order:ultrasound frequency>ultrasonic power>pH value. The results by GC-MSD analysis showed that hydroquinone was transform into small molecules through ultrasonic irradiation. The structure of the benzene ring of hydroquinone is damaged.In the research of manufacture for the ultrasonic treatment equipment, based on the previous research results and the organic wastewater technology handling PCB wastewater, we design a set of ultrasonic treatment equipment for the wastewater considering the existence defects of the treatment for the PCB organic wastewater. The process of the equipment for the wastewater was designed by consulting the relevant literature. And the process is that:wastewaterâ†'adjusted pH for the wastewaterâ†'oxidation by ultrasonic irradiation (it can be in collaboration with other oxidation technology)â†'biological treatment. The CAD equipment chart was sent to a factory for production.The ultrasound treatment equipment which manufacture in the study was applied to the PCB wastewater plant. The results show that the removal of the COD of sono-degradation was lower than Fenton treatment of wastewater. And the ultrasonic with Fenton has a certain synergy for the wastewater treatment. The optimal treatment method for PCB organic wastewater was ultrasonic treatment with Fenton. The removal rate of COD was 70.5% at least. The determination of the value of BOD5 and COD of the wastewater showed the result that the value of BOD5/CODcr was greatly enhanced. |
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