Environmental Simulation and Pollution Control State Key Joint Laboratory, School of Environment, Tsinghua University, Beijing 100084, China.
Environmental Simulation and Pollution Control State Key Joint Laboratory, School of Environment, Tsinghua University, Beijing 100084, China; State Environmental Protection Key Laboratory of Microorganism Application and Risk Control, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China.
J Environ Sci (China). 2014 Nov 1;26(11):2190-7. doi: 10.1016/j.jes.2014.09.001. Epub 2014 Sep 10.
Ozonation has been widely applied in advanced wastewater treatment. In this study, the effect of ozonation on assimilable organic carbon (AOC) levels in secondary effluents was investigated, and AOC variation of different molecular weight (MW) organic components was analyzed. Although the removal efficiencies were 47%-76% and 94%-100% for UV254 and color at ozone dosage of 10mg/L, dissolved organic carbon (DOC) in secondary effluents was hardly removed by ozonation. The AOC levels increased by 70%-780% at an ozone dosage range of 1-10mg/L. AOC increased significantly in the instantaneous ozone demand phase, and the increase in AOC was correlated to the decrease in UV254 during ozonation. The results of MW distribution showed that, ozonation led to the transformation of larger molecules into smaller ones, but the increase in low MW (<1kDa) fraction did not contribute much to AOC production. The change of high MW (>100kDa and 10-100kDa) fractions itself during ozonation was the main reason for the increase of AOC levels. Furthermore, the oxidation of organic matters with high MWs (>100kDa and 10-100kDa) resulted in more AOC production than those with low MWs (1-10kDa and <1kDa). The results indicated that removing large molecules in secondary effluents could limit the increase of AOC during ozonation.
臭氧氧化已广泛应用于高级废水处理。本研究考察了臭氧氧化对二级出水中可同化有机碳（AOC）水平的影响，并分析了不同分子量（MW）有机组分的 AOC 变化。尽管在臭氧剂量为 10mg/L 时，UV254 和颜色的去除率分别为 47%-76%和 94%-100%，但臭氧氧化几乎不能去除二级出水中的溶解性有机碳（DOC）。在 1-10mg/L 的臭氧剂量范围内，AOC 水平增加了 70%-780%。在瞬时臭氧需求阶段，AOC 显著增加，AOC 的增加与臭氧氧化过程中 UV254 的减少相关。MW 分布结果表明，臭氧氧化导致大分子向小分子转化，但低 MW（<1kDa）部分的增加并没有对 AOC 生成产生很大贡献。臭氧氧化过程中高 MW（>100kDa 和 10-100kDa）部分的变化是 AOC 水平增加的主要原因。此外，与低 MW（1-10kDa 和 <1kDa）相比，高 MW（>100kDa 和 10-100kDa）有机物的氧化导致更多的 AOC 生成。结果表明，去除二级出水中的大分子可以限制臭氧氧化过程中 AOC 的增加。
