School of Municipal and Environmental Engineering, Harbin Institute of Technology, 73 Huanghe Road, Harbin, 150090, People's Republic of China,
Environ Sci Pollut Res Int. 2014;21(13):8167-75. doi: 10.1007/s11356-014-2709-y. Epub 2014 Mar 28.
The effects of the organic loading rate (OLR) on the performance and the granular sludge characteristics of an expanded granular sludge bed (EGSB) reactor used for treating real traditional Chinese medicine (TCM) wastewater were investigated. Over 90% of the COD removal by the EGSB reactor was observed at the OLRs of 4 to 13 kg COD/(m(3) day). However, increasing the OLR to 20 kg COD/(m(3) day) by reducing the hydraulic retention time (HRT 6 h) reduced the COD removal efficiency to 78%. The volatile fatty acid (VFA) concentration was 512.22 mg/L, resulting in an accumulation of VFAs, and propionic acid was the main acidification product, accounting for 66.51% of the total VFAs. When the OLR increased from 10 to 20 kg COD/(m(3) day), the average size of the granule sludge decreased from 469 to 258 μm. There was an obvious reduction in the concentration of Ca(2+) and Mg(2+) in the granular sludge. The visible humic acid-like peak was identified in the three-dimensional excitation-emission matrix (EEM) fluorescence spectra of the soluble microbial products (SMPs). The fatty acid bond, amide II bond, amide III bond, and C-H bond bending were also observed in the Fourier transform infrared (FTIR) spectra of the SMPs. Methanobacterium formicicum, Methanococcus, and Bacteria populations exhibited significant shifts, and these changes were accompanied by an increase in VFA production. The results indicated that a short HRT and high OLR in the EGSB reactor caused the accumulation of polysaccharides, protein, and VFAs, thereby inhibiting the activity of methanogenic bacteria and causing granular sludge corruption.
采用膨胀颗粒污泥床（EGSB）反应器处理实际的传统中药（TCM）废水，考察了有机负荷率（OLR）对其性能和颗粒污泥特性的影响。在 OLR 为 4 至 13 kg COD/（m³·天）的条件下，EGSB 反应器对 COD 的去除率超过 90%。然而，通过将水力停留时间（HRT 6 h）缩短至 20 kg COD/（m³·天）来提高 OLR，会使 COD 去除效率降低至 78%。挥发性脂肪酸（VFA）浓度达到 512.22 mg/L，导致 VFA 积累，其中丙酸是主要的酸化产物，占总 VFA 的 66.51%。当 OLR 从 10 增加到 20 kg COD/（m³·天）时，颗粒污泥的平均粒径从 469 μm 减小到 258 μm。颗粒污泥中 Ca(2+)和 Mg(2+)的浓度明显降低。在可溶微生物产物（SMP）的三维激发-发射矩阵（EEM）荧光光谱中，鉴定出了可见的类腐殖酸峰。在 SMP 的傅里叶变换红外（FTIR）光谱中，还观察到脂肪酸键、酰胺 II 键、酰胺 III 键和 C-H 键弯曲。甲烷杆菌（Methanobacterium formicicum）、甲烷球菌（Methanococcus）和细菌种群的丰度发生了显著变化，这些变化伴随着 VFA 产量的增加。结果表明，EGSB 反应器中较短的 HRT 和较高的 OLR 导致多糖、蛋白质和 VFA 的积累，从而抑制产甲烷菌的活性并导致颗粒污泥腐败。
