印染废水活性污泥代谢状态光偏转快速检测法

针对现有活性污泥检测方法过程繁琐、耗时长、检测结果滞后的局限，提出了光偏转快速检测法.在污泥负荷为0.33KgCOD/（kg MLSS·d）、水力停留时间为15h的印染废水完全混合式活性污泥系统中，投放粒径4mm、具有20μm微孔结构的聚乙烯醇（PVA）凝胶小球以负载微生物，并在小球达到稳定状态后，对其表面处因外界溶液与微生物代谢产物交换产生的浓度梯度变化，借助光斑分析仪进行光偏转检测，同时测定与光偏转检测结果相对应的15h后的出水COD及COD去除率.连续10个月的检测发现，小球中富集的主要为细菌，当进水COD由91.95mg/L增至519.4mg/L时，小球的光偏转值从229.51μm增加至299.97μm，COD去除率从16.03%提高至66.99%；当DO浓度为1.5mg/L~5mg/L时，小球光偏转值在DO=4mg/L时增至最大为309.3mg/L，对应状态下COD去除率增至最大为61.18%；在pH值为6~9时，小球光偏转值在pH=7时增至最大为293.96μm，对应状态下COD去除率也达到最大值为64.83%；当重金属Cr³⁺浓度增至50mg/L时，微生物活性逐渐受到抑制，小球光偏转值在Cr³⁺浓度为20mg/L时降至269.7μm，随后随着Cr³⁺浓度的增加，微生物细胞受损，胞内物质溶出，小球光偏转值有所增大，对应状态下COD去除率从52.5%持续降低至25.73%.结果表明：该方法可快速获得活性污泥代谢状态变化信息，且依据特定条件下小球光偏转值变化能够预测随后印染废水COD的去除效果.利用三维荧光光谱初步探究了微生物代谢引发光偏转的机理，发现参与微生物代谢的主要有机物为酪氨酸、芳香类蛋白及色氨酸.

Study on rapid detection of beam deflection method for detecting metabolic status of activated sludge from printing and dyeing wastewater

Considering that limitation that cumbersome process, time-consuming and lagging detection of current activated sludge testing process, a rapid detection of beam deflection method were provided in this study. The polyvinyl alcohol gel beads with a particle size of 4mm and microporous structure of 20μm were put in the printing and dyeing wastewater complete mixed activated sludge treatment system with a sludge load of 0.33KgCOD/(kg MLSS·d) and a hydraulic retention time of 15h. The light spot analyzer was used to detecte light deflection which reflect the surface concentration gradient changes due to the exchange of external solutions and microbial metabolites after the beads reached a stable state. The corresponding COD of effluent after 15h were also measured, meanwhile the COD removal rate were calculated. After ten consecutive months of testing, it was found that the predominant microorganism is bacteria in the PVA-gel beads. The light deflection value of the beads increased from 229.51μm to 299.97μm when the influent COD increased from 91.95mg/L to 519.4mg/L, and The COD removal rate also increased from 16.03% to 66.99%. The light deflection of the beads increased with dissolved oxygen concentration and reached to the higest value 309.3μm at DO=4mg/L, meanwhile, the corresponding COD removal rate reached to the maximum which is 61.18%, when the dissolved oxygen concentration range from 1.5mg/L to 5mg/L. The light deflection of the beads increased with dissolved oxygen concentration and reached to the higest value 293.96μm at pH=7, meanwhile, the corresponding COD removal rate reached to the maximum which is 64.83%, when the pH range from 6to 9. The light deflection value of the beads decreased with the concentration of Cr³⁺ and reached to 269.7μm when the Cr³⁺ concentration at 20mg/L. The light deflection value increased with Cr³⁺ concentration continiued increased to 50mg/L, but the corresponding COD removal rate decreased form 52.5% to 25.73%, for the reason that the microbial cells are damaged and the intracellular substances are dissolved. The results show that the changes information of metabolic state in activated sludge can be quickly obtained by this method. And the changes of light deflection value of beads can be used to predict the subsequent COD concentration removal effect of printing and dyeing wastewater under specific conditions. Three-dimensional fluorescence spectroscopy were also used to explore the mechanism of microbial metabolism triggering light deflection. And the results showed that the main organic substances involved in microbial metabolism are tyrosine, aromatic proteins and tryptophan.