电化学氧化和臭氧化预处理酸性化工废水的效能研究

保持一定酸度条件下对比了电化学氧化和臭氧氧化预处理酸性化工废水的效能（废水原pH 0.85）. 结果表明，在废水中添加2 g·L^-1 NaCl电化学氧化预处理效果较佳，30 mA·cm^-2条件下电解20 min后水样的CODCr（化学需氧量）去除率达43.4%，BOD₅/COD_Cr（生化需氧量与化学需氧量的比值）值从原来的0.034上升至0.14，可生化性明显提高. 单独臭氧化仅在pH 7.0才能取得一定的预处理效能. Ti(Ⅳ)/O₃/H₂O₂高级氧化体系在pH 2.85条件下亦有较好的预处理效果，16 min后水样COD_Cr去除率达22.9%，BOD₅/COD_Cr值则提高至0.072.

A Comparative Study in Pretreatments of Acid Chemical Wastewater by Electrochemical Oxidation and Ozonation

Under the condition of keeping certain acidity, the pretreatment efficiency of an acid chemical wastewater (pH 0.85) by electrochemical oxidation was compared with that by ozonation. The results showed that the electrochemical oxidation pretreatment could obtain a better result than the ozonation at pH 0.85. After the addition of 2 g·L^-1 NaCl and with the electrochemical oxidation pretreatment at 30 mA·cm^-2, the removal rate of chemical oxygen demand (CODCr) reached 43.4%, and the value of biochemical oxygen demand/chemical oxygen demand (BOD₅/COD_Cr) also increased from 0.034 to 0.14 in 20 minutes, indicating significantly improvement in the biodegradability of the wastewater. However, the ozonation alone had a low pretreatment efficiency at pH 0.85, and could only become as effective as those done by the electrochemical oxidation pretreatment at pH 7.0. A ozone-based advanced oxidation technology, Ti(Ⅳ)/O₃/H₂O₂, was also relatively effective at pH 2.85. The value of 22.9% for the removal rate of CODCr could be obtained and the value of BOD₅/COD_Cr went up from 0.034 to 0.072 in 16 min.