UV/O3-Na2S2O8处理活性炭再生冷凝废水效能及机理

EFFICIENCY AND MECHANISM OF UV/O-NaSO IN TREATING ACTIVATED CARBON REGENERATION CONDENSATE WASTEWATER

过热蒸汽法再生活性炭的过程中会产生大量含难降解有机物的冷凝废水,为去除冷凝废水中难降解COD,提高可生化性,采用紫外/臭氧活化过硫酸盐(UV/O3-Na2S2O8)氧化体系对活性炭再生冷凝废水进行处理,考察了O3投加量、初始pH和Na2S2O8投加量等因素对有机物处理效能的影响,并采用红外光谱、紫外-可见光谱和三维荧光等表征手段探究了冷凝废水处理过程中的变化机理。结果表明:当O3投加量为30 mg/L,pH值为9.0,Na2S2O8投加量为0.4 g/L时,在120 min内对冷凝废水的COD去除率达到82.1%,色度(CN)去除率达到86.3%。冷凝废水可生化性得到提高,BOD5/COD值由0.17提升至0.46。由冷凝废水溶解性有机物(DOM)的表征可知,DOM中的腐殖质和发色基团被持续氧化,芳构化程度降低,色氨酸类有机物得到有效去除。结论表明,UV/O3-Na2S2O8氧化体系可有效去除冷凝废水中的难降解有机物。

During the regeneration of activated carbon by superheated steam method,a large amount of condensed wastewater containing refractory organics will be produced. In order to remove the refractory COD in the condensed wastewater,improve the biodegradability and facilitate the subsequent biodegradation,UV/ozone activated persulfate (UV/O3-Na2S2O8) oxidation system was used to treat the activated carbon regeneration condensate wastewater. The effects of ozone dosage,initial pH and Na2S2O8 dosage on the treatment efficiency of the organics were investigated. The changes in the treatment process of the condensate wastewater were investigated by means of infrared spectrum,UV-Vis spectrum and three-dimensional fluorescence.The results showed that when the dosage of ozone was 30 mg/L,pH was 9. 0,and Na2S2O8 dosage was 0. 4 g/L,the removal rate of COD and chroma (CN) was 82. 1% and 86. 3%,respectively. The biodegradability of condensed wastewater was improved,and the BOD5/COD value was increased from 0. 17 to 0. 46. It could be found from the characterization of dissolved organic matter (DOM) in condensed wastewater that humus and chromophore in DOM were oxidized continuously,and the aromatization degree was reduced. Tryptophan organics were effectively removed. The results showed that UV/O3-Na2S2O8 oxidation system could effectively remove the organics in the condensed wastewater.