焦化废水中不同极性组分的光谱分析及可生物降解特性

Spectral analysis and biodegradation characteristics of different polar fractions in coking wastewater

焦化废水是典型难降解工业有机废水,构成其成分的复杂及种类的繁多使其难以实现高效的生物降解过程,制约了水处理的水质达标.为了探明其中生物降解强抑制组分,采用DAX-8大孔树脂将焦化废水分离出疏水酸性组分(HOA)、疏水碱性组分(HOB)、疏水中性组分(HON)和亲水性组分(HIS)等4种极性不同的组分,分析了各组分的有机物含量分布,紫外吸收光谱和三维荧光光谱,并用两种方法考察了各组分的可生物降解性能.结果表明,HOA是主要的有机组分,其COD和TOC分别占比55.9%和56.8%;HOA也是主要的芳香物质及荧光组分,而HON是芳香构造化程度最高和类腐殖质占比P(Ⅲ+Ⅴ)最高的组分;各组分的BOD5/COD值及脱氢酶活性的抑制结果显示其难降解程度依次为HON>HOB>HIS>原水>HOA,而HON是焦化废水中生物抑制最强组分,其BOD5/COD值仅为0.21±0.02,对脱氢酶活性的抑制达到38.5%;SUVA和P(Ⅲ+Ⅴ)与可生物降解性的关联分析发现,焦化废水中难降解组分并不都是芳香性化合物造成的,类腐殖质对其中难降解有机组分的指示作用相比SUVA更加灵敏.

Coking wastewater is a typical refractory industrial organic wastewater with complicated composition; efficient biodegradation of coking wastewater is hard to achieve,thus making its effluent hard to meet the discharge standard. In order to ascertain its refractory components,DAX-8 resin was applied to separate coking wastewater into four different polar fractions： hydrophobic acids（ HOA）,hydrophobic bases（ HOB）,hydrophobic neutrals（ HON） and hydrophilic substances（ HIS）. Then the organic content distribution,UV absorption spectra,three-dimensional fluorescence excitationemission matrix（ 3D EEMs） of each polar fractions were analyzed and their biodegradability was evaluated. The results showed that HOA was the main organic component,accounting for 55. 9% and 56. 8% of the total COD and TOC,respectively. HOA was also a major constituent of aromatic and fluorescent substances,but HON had the highest degree of aromatic structure and proportion of humic-like substances P（ Ⅲ＋Ⅴ）. The BOD5/ COD values and the dehydrogenase activity inhibition of different polar fractions showed that the order of refractory degree was HON〉 HOB〉 HIS raw water 〉HOA.It was found that HON was the most refractory component for biodegradation inhibition in coking wastewater,whose BOD5/ COD value was only 0.21 ±0.02 and the inhibition degree of dehydrogenase activity reached 38.5%. The correlations among SUVA,P（ Ⅲ＋Ⅴ）and biodegradability revealed that not all refractory substances in coking wastewater were aromatic compounds,while humic-like matter（ Ⅲ ＋ Ⅴ） was more sensitive to indicate refractory substances compared to SUVA.