臭氧及臭氧/双氧水对污水厂二级出水中有机污染物的去除试验

Removal of Organic Pollutants in Secondary Effluent of WWTP by O_3 and/or O_3/H_2O_2 Process

以某城市污水处理厂二级出水为原水,采用批量试验方法,通过调整臭氧和双氧水剂量,研究臭氧氧化和臭氧/双氧水组合工艺对水中有机物的去除规律。结果表明:在臭氧剂量为3.5 mg/L时,水中色氨酸类芳香族蛋白质、富里酸类物质、微生物代谢产物和腐殖质类物质的去除率分别为80.0%、79.3%、85.4%和84.1%;当臭氧剂量增加到10mg/L时,COD、UV_(254)、TOC和色度的去除率分别为26.6%、59.5%、9.6%和88.2%。水中pH值的升高促进臭氧的吸收,当臭氧投加量为33.5 mg/L时,pH值=11时的臭氧吸收率比pH值=3时提高31.1%。当臭氧剂量<13 mg/L时,投加双氧水的处理效果无明显影响;当臭氧剂量≥13 mg/L,且双氧水与臭氧的摩尔比值在1.25内时,双氧水的投加使得出水COD和TOC随双氧水与臭氧摩尔比值的增加逐渐降低,最大去除率分别为37.7%和16.6%,较臭氧单独处理时分别提高10.7%和5.4%。

Removal laws of organic pollutants in the secondary effluent of a WWTP by O_3 and O_3/H_2 O_2 processes were studied through adjusting the dosages of O_3 and H_2 O_2 in batch test. Results showed that when the dosage of 03 was 3. 5 mg/L, removal rates of tryptophan aromatic protein, fulvic acid,microbial metabolites and humic acid were 80.0%,79.3%, 85.4% and 84.1%,respectively. When O_3 dosage was increased to 10 mg/L,removal rates of COD,UV_(254),TOC and chromaticity were 26. 6%,59. 5%,9. 6% and 88.2%,respectively. Absorption rate of O_3 was enhanced with the increase of pH value, as when O_3 dosage was33. 5 mg/L, the adsorption rate of O_3 under pH value of 11 was 31. 1% higher than that under pH value of 3. When O_3 dosage was under 13 mg/L, no obvious quality improvement of the treated water was found by adding H_2 O_2. When O_3 dosage exceeded 13 mg/L and the molar ratio of O_3/H_2 O_2 was below 1. 25, adding hydrogen peroxide made COD and TOC of the effluent decreased with the increase of molar ratio of O_3/H_2 O_2. The maximum removal rates of COD and TOC were 37. 7% and 16.6%,respectively, and compared to the treatment by O_3 only, the removal rates were increased by 10. 7% and 5. 4%.