Research Institute of Environmental Engineering & Nano-Technology, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, Guangdong, China; Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, Guangdong, China; School of Environment, Tsinghua University, Beijing 100084, China.
Research Institute of Environmental Engineering & Nano-Technology, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, Guangdong, China; Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, Guangdong, China; School of Environment, Tsinghua University, Beijing 100084, China; Tsinghua-Berkeley Shenzhen Institute, Tsinghua University, Shenzhen 518055, Guangdong, China.
Sci Total Environ. 2019 May 10;664:116-126. doi: 10.1016/j.scitotenv.2019.02.019. Epub 2019 Feb 2.
Ferrous dosing is used to reduce phosphorus concentration and alleviate polymeric membrane fouling in membrane bioreactor (MBR). However, limited studies have been conducted to investigate the impacts of ferrous dosing on ceramic membrane fouling, nutrient removal efficiency and microbial community. Accordingly, the aim of this study was to investigate the effect of intermittent ferrous dosing with Fe/P molar ratios of 2 and 1 (with a dosing frequency of every two days) on the overall nutrient removal, functional microbial changes and membrane fouling in ceramic membrane bioreactors (CMBR) in treatment of wastewater. TP concentration of 10 mg/L in influent decreased to 1.94 ± 0.62 mg/L (control), 0.38 ± 0.22 mg/L (Fe/P = 1) and 0.31 ± 0.18 mg/L (Fe/P = 2) in the effluent, respectively. Meanwhile, the effluent total nitrogen (TN) concentrations with Fe/P = 1 treatment (6.80 ± 2.02 mg/L) and Fe/P = 2 treatment (5.12 ± 2.28 mg/L) were lower than that of the control (7.72 ± 2.36 mg/L). Compared to Fe/P = 1, the TN removal performance was better for Fe/P = 2 mainly due to the increased abundance of denitrifying bacteria (Zoogloea and Acinetobacter). In addition, excess iron dose might have toxic effects on bacterial physiology, however the Fe concentrations that cause cell damage vary for different bacteria. The relative abundance of Zoogloea (aerobic denitrifying bacteria) continuously increased with ferrous addition (Fe/P = 2), while other bacteria including Dechloromonas, Hyphomicrobium and Thauera (anoxic denitrifying bacteria), Nitrospira (nitrifying bacteria) and Candidatus Accumulibacter (phosphorus accumulating organism) decreased sharply. Furthermore, membrane fouling was effectively moderated by ferrous dosing and Fe/P = 1 treatment showed improved membrane fouling mitigation than Fe/P = 2. Overall, intermittent ferrous addition in CMBR with Fe/P molar ratio of 1 was beneficial to the removal of nutrients (TP, TN and organics), enhanced succession of microbial community and membrane fouling mitigation.
亚铁投加用于降低磷浓度并减轻膜生物反应器（MBR）中的聚合膜污染。然而，对于亚铁投加对陶瓷膜污染、营养物去除效率和微生物群落的影响，研究还很有限。因此，本研究的目的是研究亚铁投加（Fe/P 摩尔比为 2 和 1，投加频率为每两天一次）对处理废水中陶瓷膜生物反应器（CMBR）的整体营养物去除、功能微生物变化和膜污染的影响。进水 TP 浓度为 10mg/L，出水中分别降至 1.94±0.62mg/L（对照）、0.38±0.22mg/L（Fe/P=1）和 0.31±0.18mg/L（Fe/P=2）。同时，Fe/P=1 处理和 Fe/P=2 处理的出水总氮（TN）浓度（分别为 6.80±2.02mg/L 和 5.12±2.28mg/L）均低于对照（7.72±2.36mg/L）。与 Fe/P=1 相比，Fe/P=2 的 TN 去除性能更好，主要是因为反硝化菌（动胶菌属和不动杆菌属）的丰度增加。此外，过量的铁剂量可能对细菌生理产生毒性作用，但不同细菌造成细胞损伤的铁浓度有所不同。随着亚铁的添加，Zoogloea（好氧反硝化菌）的相对丰度不断增加（Fe/P=2），而其他细菌包括 Dechloromonas、Hyphomicrobium 和 Thauera（缺氧反硝化菌）、Nitrospira（硝化菌）和 Candidatus Accumulibacter（聚磷菌）的丰度急剧下降。此外，亚铁投加可有效缓解膜污染，Fe/P=1 处理比 Fe/P=2 处理更能减轻膜污染。总体而言，CMBR 中 Fe/P 摩尔比为 1 的间歇亚铁添加有利于营养物（TP、TN 和有机物）的去除、增强微生物群落的演替和膜污染的缓解。
