Li Ren, Yu Li-Fang, Zhang Xing-Xiu, Dai Zi-Cheng, Hua Si-Si, Peng Dang-Cong
School of Municipal and Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China.
Key Laboratory of Northwest Water Resource, Environment and Ecology, Ministry of Education, Xi'an University of Architecture and Technology, Xi'an 710055, China.
Huan Jing Ke Xue. 2020 Aug 8;41(8):3691-3698. doi: 10.13227/j.hjkx.201911234.
The long-term effects of a decreasing temperature on the nitrification performance, biofilm characteristics, and nitrifier community in a moving-bed biofilm reactor (MBBR) and integrated fixed-film activated sludge (IFAS) system were investigated at various temperatures (20, 15, and 10℃) to explore the adaptability of nitrifying biofilm systems to low temperatures. During the experiment, the extracellular polymeric substances (EPS) in the biofilms increased with decreasing temperature, which resulted in an increased biofilm mass and thickness. As there was only a biofilm phase in the MBBR to remove ammonia, the part of the carriers in the MBBR at 10℃ became plugged, which partially led to a deterioration in the effluent water quality. This indicated that the IFAS system was more adaptable to low temperatures than was the MBBR. Meanwhile, the results for the nitrifier activities showed that, although the nitrification contribution rate of the suspended phase in the IFAS system always dominated during the experiment, that of the fixed phase with regards to the ammonia uptake rate (AUR) gradually increased from 30.72% at 20℃ to 39.85% at 10℃. This indicated that the biofilm played an enhanced role in nitrification in the IFAS system. Moreover, the qPCR results revealed that the nitrifier copies of the number of biofilms increased slightly with decreased temperature, and coincided with an increase in biomass, which partially compensated for the decreased nitrification activity. These findings provide a theoretical basis for the application of the biofilm systems to wastewater treatment.
在不同温度（20℃、15℃和10℃）下，研究了温度降低对移动床生物膜反应器（MBBR）和一体化固定膜活性污泥（IFAS）系统中硝化性能、生物膜特性及硝化菌群落的长期影响，以探索硝化生物膜系统对低温的适应性。实验过程中，生物膜中的胞外聚合物（EPS）随温度降低而增加，导致生物膜质量和厚度增加。由于MBBR中只有生物膜阶段用于去除氨氮，10℃时MBBR中的部分载体发生堵塞，这在一定程度上导致了出水水质恶化。这表明IFAS系统比MBBR更适应低温。同时，硝化菌活性结果表明，虽然实验期间IFAS系统中悬浮相的硝化贡献率始终占主导，但固定相的氨氮摄取率（AUR）从20℃时的30.72%逐渐增加到10℃时的39.85%。这表明生物膜在IFAS系统的硝化过程中发挥了增强作用。此外，qPCR结果显示，生物膜中硝化菌的拷贝数随温度降低略有增加，且与生物量的增加一致，这在一定程度上弥补了硝化活性的降低。这些研究结果为生物膜系统在污水处理中的应用提供了理论依据。
