滇池入湖污水处理厂尾水COD降解过程及光谱特征

选取滇池典型入湖污水处理厂尾水,模拟研究了其COD自然条件下的降解过程及光谱特征,探讨污水处理厂尾水排放对滇池水体COD的影响。结果表明:1)尾水COD以溶解态为主,直接汇流进入滇池;其自然降解率较低,易在湖体内累积;COD_Cr降解率为28.9%,降解过程符合方程C=-2.46ln t+29.018(R ²=0.932 2);COD_Mn降解率为15.8%,降解过程符合方程C=-0.348ln t+7.473(R ²=0.995 7)。2)紫外-可见光谱和三维荧光光谱特征表明,尾水COD主要以类富里酸物质为主,其降解过程结构相对稳定,芳香环结构稍有增加,进一步证实尾水COD大部分滞留在水体中,如水体交换不及时,会逐步累积。3)随着滇池流域污水处理能力的提升,污水处理厂排水是滇池水量的重要来源,且COD具有难降解特征,近年来滇池COD的升高与入湖污水处理厂尾水排放密切相关。

Spectroscopic analysis and degradation kinetics study of COD in sewage plant effluent into Dianchi Lake

Representative effluent from sewage treatment plants in Dianchi Lake was selected to simulate and investigate the degradation process and spectral characteristics of COD under natural conditions, and to explore the influence of the effluent on the concentration of COD in Dianchi Lake. The results show that: 1) The COD in the effluent from sewage plants occurred mainly in dissolved states and flew directly into Dianchi Lake; the degradation rate of CODCr was 28.9% and was quite low under the experiment condition, and the degradation process accords with the equation C=-2.46ln t+29.018 (R 2=0.932 2). COD was easy to accumulate under such condition. The degradation rate of CODMn was 15.8%, and the degradation process accords with the equation C=-0.348ln t+7.473 (R 2=0.995 7). 2) UV Vis spectroscopy and three-dimensional fluorescence spectra characteristics show that the COD in the effluent from sewage plants was mainly in the category of fulvic acid. The structure of COD in the effluent from sewage plants was relatively stable in the process of degradation. The slightly increasing of aromatic part of COD further confirmed that most organic compounds in the effluent from sewage plants remained in the water and the COD would gradually accumulate if the water did not change timely. 3) With the increase of the sewage treatment capacity in the lake basin, the effluent from sewage plants had become the main source of the water quantity in Dianchi Lake. And as the COD in the effluent has the refractory characteristic, the increasing of the COD concentration in recent years was closely related to the discharge of effluent from the sewage plants.