不同碳源反硝化滤池进出水中溶解性有机物对比分析

Comparison and Analysis of Dissolved Organic Matters in Influent and Effluent of Denitrification Biofilter with Different Additional Carbon Sources

以某城市污水处理厂二级出水为反硝化滤池进水,利用分子排阻色谱、三维荧光(EEM)及溶解性微生物代谢产物(SMP)测定等不同分析方法对不同碳源反硝化生物滤池进出水中的溶解性有机物(DOM)进行对比研究。结果表明,滤池进水DOM中小分子物质含量最高,其中分子量为1 kDa的有机物约占总有机物的50%,分子量>10 kDa的大分子有机物约占7%。经过反硝化滤池,出水有机物种类不变,小分子有机物出水浓度下降为进水的50%,说明滤池对小分子物质有一定的去除作用。SMP测定结果表明,滤池进水中主要的SMP物质为腐植酸,约占SMP总含量的70%。在整个过滤周期内,SMP的总量变化不大,反冲洗气水冲和水冲阶段SMP的浓度增加显著。EEM分析表明,滤池正常运行时,进出水中的DOM主要成分为可见腐植质(λ_(ex)/λ_(em)=330/425)和UV腐植质(λ_(ex)/λ_(em)=230/430);反冲洗阶段,DOM含量增加,且出现类蛋白、类色氨酸;整个过滤周期内有机物的含量基本不变,说明反硝化生物滤池不能对腐植酸类物质进行降解。

Different analytical methods,such as size exclusion chromatography,three-dimensional fluorescence(EEM)and determination of soluble microbial products(SMPs),were used to compare and analyze dissolved organic matters(DOMs)in influent and effluent of denitrification biofilters with different additional carbon sources,using the secondary effluent from a municipal wastewater treatment plant as the feed.The results showed that DOMs of the highest content in the influent of denitrification filter were small molecules,and those with molecular weight(MW)=1 kDa accounted for 50%of the total organic matters,while macromolecular substances with MW>10 kDa accounted for about 7%.After denitrification biofilter,the type of organic matters in the effluent remained unchanged,and the concentration of small molecules decreased to 50%of the influent,indicating the removal effect of biofilter on small molecules.The results of SMP determination showed that the main SMP substance in the influent was humic acid,accounting for about 70%of the total SMPs.The variation of SMPs in the whole filtration cycle were not significant,while the concentration of SMPs in the stages of backwash and water flushing increased significantly.Analysis of EEM spectra showed that the main components of DOMs in influent and effluent were visible humus(λex/λem=330/425)and UV humus(λex/λem=230/430)during normal operation.During backwashing stage,DOMs content increased,and proteinoids and tryptophan appeared.Content of organic matters in the whole filtration cycle basically stayed unchanged,indicating that the biofilter could not degrade humic acid.