水力停留时间对双循环厌氧反应器处理中药废水污泥特性的影响

研究了不同水力停留时间(HRT,24 h、18 h、15 h、12 h)对双循环(DC)厌氧反应器处理中药废水效能的影响,并对颗粒污泥的粒径分布(PSD)、胞外聚合物(EPS)、微生物群落等变化情况进行了分析。结果表明,HRT由24 h缩短为12 h后,DC厌氧反应器对COD的去除率仍在90%以上。虽然出水中乙酸含量升高到339.69mg·L-1,但未造成VFA的过度累积;出水中辅酶的荧光吸收峰有所降低,而类腐殖酸与类富里酸的吸收峰增强,不适宜再继续降低HRT。随着HRT的缩短,颗粒污泥的EPS总量、蛋白含量、多糖含量均降低,其中酪氨酸对于保持污泥的稳定性发挥着重要作用。而磷脂脂肪酸分析(PLFA)表明,HRT缩短对于DC厌氧反应器第2反应区内微生物群落分布影响显著,革兰阳性菌由原来占总脂肪酸生物量的44.24%下降到32.69%,而革兰阴性菌由32.69%增大到38.66%。

Influence of hydraulic retention time on sludge characteristics of DC anaerobic reactor for treating traditional Chinese medicine wastewater

The influence of hydraulic retention time (HRT, 24, 18, 15 and 12 h) on the performance of double circle (DC) anaerobic reactor for treating traditional Chinese medicine wastewater was investigated. Additionally, the characteristics of granular sludge were studied, including particle size distribution (PSD), extracellular polymeric substances (EPS), and distribution of microbial communities. When HRT was reduced from 24 h to 12 h, the DC anaerobic reactor demonstrated good COD removal of 90%. Although concentration of acetate increased to 339.69 mg·L^-1, the process was operating favorably without acidification. But humic acid-like and fulvic acid-like absorption peaks were stronger and coenzyme F₄₂₀ absorption was weaker in the EEM spectra of soluble microbial products (SMP) at HRT 12 h. It was not recommended to further reduce HRT. The contents of EPS, protein, and polysaccharide decreased in the sludge at HRT 12 h, and tyrosine played an important role in maintaining stability of the sludge. The phospholipid fatty acids analysis showed that reducing HRT affected significantly distribution of microbial community in the second reaction area of the DC anaerobic reactor. Gram-positive bacteria decreased from 44.24% to 32.69%, while gram-negative bacteria increased from 32.69% to 38.66%.