| Owing to many kinds of pollutants, complex compositions and high toxicity, pharmaceutical wastewater is a major problem of wastewater treatment. Conventional biological treatments were difficult to achieve the desired results. Therefore, in order to improve biodegradability of wastewater, effective pretreatment technology is needed. Pretreatment technologies include flotation, coagulation, adsorption and advanced oxidation processes (AOPs). AOPs can effectively remove the organic pollutants of high stability and refractory. So the toxicity is reduced, and the biodegradability is increased.Ozone (O3) advanced oxidation technology is one of AOPs. This method which used combined with one or more other treatment methods through O3, including ultraviolet (UV), hydrogen peroxide (H2O2), ultrasound (US) and solid catalyst etc, catalyzing O3 into hydroxyl radicals (·OH) which is stronger oxidability and lower reaction selectivity, solved problems such as the selectivity of separating O3 and harmful intermediate products and so on, improving the oxidation efficiency of O3.In this paper, O3 oxidation will be used coupled with UV and H2O2, berberine wastewater as representative pharmaceutical wastewater, to research the treatment effect and influencing factors of berberine wastewater, which is hard to degrade, through the advanced oxidation coupled techniques such as O3, UV/O3 and UV/H2O2/O3. Considering the treatment effect evaluation and economic analysis, the optimal oxidation process of treating berberine wastewater was determined, and the mechanism and kinetics of O3 advanced oxidation technology was preliminarily analysed.The experimental results showed that, the treatment effect of using O3 oxidation process separately is low, and it took long processing time. Both UV and H2O2 can strengthen O3 oxidation produce more active component·OH, when the techniques of coupling O3 is more, the treatment effect of using advanced oxidation technology is the better. When the berberine wastewater is of low concentration, the treatment effect is good with any O3 advanced oxidation technology. For the concentration of berberine wastewater is 300 mg/L, the pH is 7, the best operation condition of using UV/H2O2/O3 process is:the volume of H2O? is 2.00 mL/L, the concentration of O3 is 14.05 mg/L/min, pH> 7, that is, alkaline environment, the mole ratio of O3 and H2O2 is 0.3. When pH is 11, the reaction time is 45 min, the removal rate of berberine wastewater reached as high as 96.49%. But for berberine wastewater of high concentration levels, UV/O3 oxidation process is a good pretreatment technology, comprehensively considering the treatment effect and economic cost. For the 1000 mg/L simulated berberine wastewater with pH value of 5, the best operating conditions of O3/UV process is:the flow of air was 3 L/min, the concentration of O3 was 14.05 mg/L/min, when the ozone dosage was 279 mg/L and the treatment time was 45 min, the berberine removal efficiency reached 81.2%. As the initial concentration of berberine wastewater increased, the berberine and CODCr removal efficiencies decreased gradually. Finally, O3/UV process was used to treat the real berberine wastewater. Under this condition, O3/UV process was used to treat the real berberine wastewater. It was verified that 03/UV process was an effective pretreatment technology that greatly improved the biodegradability of berberine wastewater, with an increase of BOD5/CODCr ratio by 16 times from 0.02 to 0.256.Kinetic analysis demonstrated that, during the optimum reaction time, the process of O3 advanced oxidation technology on treatment of berberine hydrochloride wastewater is a first-order reaction:there is lnCt,=ln C0-k0t, and the reaction rate constants of berberine hydrochloride and COD are 0.00794 min-1 and 0.00216 min-1, respectively.UV-Vis spectra and GC-MS spectrogram analysis showed that the activated-OH, produced in the O3 advanced oxidation process, can degrade the molecular structure of characteristics pollutants such as berberine in the wastewater, convert them into other small molecules, and improve the biochemical quality of the wastewater. |
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