Article
Environmental Sciences
Liqi Peng, Feifei Wang, Di Zhang, Chao Fang, Jan Peter van der Hoek, Wenhai Chu
Summary: The high chlorine dosages in wastewater treatment plants during the COVID-19 pandemic may lead to increased DBPs formation, posing threats to the aquatic ecosystem and public health downstream. Biological treatment processes were found to decrease some DBPs while increasing the formation of others, especially brominated DBPs, despite the efficient removal of organic matters. This study provides insights into DBP risk control in wastewater treatment, particularly during the ongoing pandemic.
SCIENCE OF THE TOTAL ENVIRONMENT
(2021)
Article
Agricultural Engineering
Qianwen Sui, Fei Di, Junya Zhang, Hui Gong, Li'an Jiang, Yuansong Wei, Jie Liu, Jia Lin
Summary: This study confirmed the feasibility of anaerobic ammonia oxidation as a tertiary nitrogen removal process, and identified the main nitrogen removal pathway using anammox in an upflow fixed-bed reactor. It also investigated the cooperation mechanism among AOA, AOB, and AnAOB in the inner-layer of biofilm in the reactor.
BIORESOURCE TECHNOLOGY
(2021)
Article
Environmental Sciences
Ya-nan Luan, Yue Yin, Gongfa Chang, Feng Zhang, Changqing Liu
Summary: This study investigates the impact of anaerobic duration on phosphorus removal in the reversed AAO process. The results show that the amount of released P and stored PHAs can be controlled by different anaerobic durations, but higher stored PHAs do not guarantee higher P removal efficiency. Additionally, extending the anaerobic duration has a significant effect on microbial activity, and the highest P removal efficiency is achieved at an anaerobic duration of 4 hours.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
(2023)
Article
Engineering, Environmental
Weihua Zhao, Meixiang Wang, Meng Bai, Zhaoshuo Tian, Shanyun Wang, Zhongwei Wang
Summary: In this study, DEAMOX technology was successfully applied in an A/O-SBBR system to improve nitrogen removal from real low-carbon/nitrogen domestic wastewater. Excellent nitrification performance was achieved in the N-SBBR, while DEAMOX was achieved in the An-SBBR. The addition of anammox bacteria resulted in an improvement in total inorganic nitrogen removal efficiency.
JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING
(2022)
Article
Engineering, Environmental
Qinzhiy Li, Dieter Schild, Mathieu Pasturel, Johannes Luetzenkirchen, Khalil Hanna
Summary: This study demonstrated the sensitivity of the reactivity of layered manganese oxide to dynamic anoxic/oxic conditions. Under oxic conditions, the surface-catalyzed oxidation of Mn(II) increased the removal efficiency of the target contaminant OFL. However, an increase in Mn(II)/MnO2 molar ratio suppressed MnO2 reactivity, likely due to competitive binding between Mn (II) and OFL or modification in MnO2 surface charge. Monovalent cations compensation and their effect on MnO2 particle aggregation were observed under oxic conditions. The enhancement in the removal efficiency of OFL was confirmed in the dynamic two-step anoxic/oxic process, which emulates oscillating redox conditions in environmental settings.
JOURNAL OF HAZARDOUS MATERIALS
(2022)
Article
Engineering, Multidisciplinary
Han HongGui, Zhang JiaCheng, Du ShengLi, Sun HaoYuan, Qiao JunFei
Summary: A robust optimal control (ROC) strategy was developed to improve the operation performance of A(2)O reactors, utilizing systematic evaluation criteria, an optimization algorithm, and a fuzzy neural network. The strategy showed great potential for application in real A(2)O reactors.
SCIENCE CHINA-TECHNOLOGICAL SCIENCES
(2021)
Article
Engineering, Environmental
Kwami Coco Dzidula Agbewornu, Tanveer M. Adyel, Jun Zhai
Summary: The study found that under optimized conditions, the hybrid oxidation ditch (H-OD) achieved effective removal of chemical oxygen demand and ammonium, with an average removal rate of total nitrogen at 72.8% and simultaneous nitrification and denitrification at 42.7%. Maintaining a suitable carbon/nitogen ratio can achieve complete nitrification and denitrification.
JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING
(2021)
Article
Environmental Sciences
Lingna Xu, Ji Zhao, Jimiao Wang, Ruihuan Gu, Yong Qu, Jianhui Yin, Deshuang Yu, Zhengda Yu, Juan Feng, Xiaoxia Wang
Summary: This study aimed to verify whether AOA could be established in an ongoing anaerobic-oxic (AO) system. Contrary to expectations, under AOA mode, little nitrate reduction indicated the failure of endogenous denitrification (ED).Additionally, within the long-term AOA operation, nitrification weakened due to low dissolved oxygen and long unaerated duration.
SCIENCE OF THE TOTAL ENVIRONMENT
(2023)
Article
Biotechnology & Applied Microbiology
Weihua Zhao, Yanyan Wang, Meng Bai
Summary: The enhancement of nitrogen removal was achieved through the nitritation/anammox process in an anaerobic/oxic/anoxic (AOA) system with integrated fixed biofilm activated sludge. Nitritation was initially accomplished by inhibiting ammonia residues using free nitrous acid (FNA), and anaerobic ammonia oxidizing bacteria (AnAOB) were subsequently introduced into the system to enable nitritation coupled with anaerobic ammonia oxidation (anammox). The results demonstrated that the nitritation/anammox pathway significantly enhanced nitrogen removal efficiency to 88.9%. Microbial analysis revealed the enrichment of ammonia oxidizing bacterium (AOB) Nitrosomonas on the biofilm (5.98%) and in the activated sludge (2.40%), while the AnAOB Candidatus Brocadia was detected on the biofilm at a proportion of 0.27%. The successful achievement and maintenance of nitritation/anammox were attributed to the accumulation of functional bacteria.
BIOPROCESS AND BIOSYSTEMS ENGINEERING
(2023)
Article
Engineering, Environmental
Wenjiao Sang, Dong Li, Yongjian He, Cheng Zhan, Qian Zhang, Cuihua Li, Rajendra Prasad Singh
Summary: The study investigated the impact of 2450 MHz electromagnetic wave loading on returned sludge for sludge reduction in anaerobic/anoxic/oxic process. The results showed improved total nitrogen removal and sludge reduction, along with enhanced microbial activity in the EWRS-A(2)O process compared to conventional A(2)O. Despite an increase in total phosphorus concentration, minimal effects on COD and ammonia nitrogen were observed.
PROCESS SAFETY AND ENVIRONMENTAL PROTECTION
(2021)
Article
Environmental Sciences
Qinyuan Lu, Junqing Zhou, Ge Zhu, Chong Tan, Songyun Chen, Xiaohui Zhu, Ning Yan, Yongming Zhang, Qiuen Xu, Bifeng Pan, Bruce E. Rittmann
Summary: The A/O process in wastewater treatment involves recirculating mixed liquor between anoxic and oxic tanks. The exchange of biomass between these tanks can affect the rates of denitrification and nitrification. Bench-scale experiments showed that higher biomass exchange led to lower rates of denitrification and nitrification. The study also confirmed the similarity of microbial communities in A/O processes at different scales.
SCIENCE OF THE TOTAL ENVIRONMENT
(2022)
Article
Microbiology
Gabriela F. Paredes, Tobias Viehboeck, Raymond Lee, Marton Palatinszky, Michaela A. Mausz, Siegfried Reipert, Arno Schintlmeister, Andreas Maier, Jean-Marie Volland, Claudia Hirschfeld, Michael Wagner, David Berry, Stephanie Markert, Silvia Bulgheresi, Lena Koenig
Summary: The study investigated the effect of oxygen on Candidatus Thiosymbion oneisti, a gammaproteobacterium living on marine nematodes. Surprisingly, sulfur oxidation genes were upregulated under anoxic relative to oxic conditions. In addition, stress-related genes were upregulated under oxic conditions, suggesting the symbiont's response to oxygen availability.
Article
Environmental Sciences
Jianwei Liu, Jingyun Ge, Xinyue Kang, Hongyu Tian
Summary: This study investigated the fugitive bioaerosols from two wastewater treatment plants (WWTPs) with anaerobic-anoxic-oxic (AAO) processes and proposed control measures based on the results. The bioaerosols were found to be composed of microorganisms from dominant genera and water-soluble ions dominated by SO42-. Factors such as TSP, RH, WS, Ca2+, NH4+, Na+, Cl-, NO3-, and K+ had positive effects on most dominant genera, while T and SO42- had negative effects. Source analysis showed that the bioaerosols mainly originated from sewage, sludge, or background air of WWTPs. Based on the characteristics of bioaerosols and source analysis, targeted control measures were proposed. This study provides theoretical basis and ideas for controlling bioaerosols in WWTPs with AAO processes.
JOURNAL OF ENVIRONMENTAL MANAGEMENT
(2023)
Article
Agricultural Engineering
Liyan Deng, Yongzhen Peng, Jianwei Li, Ruitao Gao, Wenyu Li, Rui Du
Summary: Advanced nitrogen and phosphorus removal was achieved in a single-stage suspending-sludge system using a novel Anaerobic/Oxic/Anoxic (AOA) strategy for over 200 days. The system showed stable nitritation with high activity of ammonia oxidation bacteria and improved anammox performance without initial inoculation. The study provided new insights into advanced nutrient removal with comprehensible regulation and reduced aeration requirement.
BIORESOURCE TECHNOLOGY
(2021)
Article
Engineering, Environmental
Xuejie Zhang, Qianqian Jia, Jia Deng, Feng Wu, Li-Zhi Huang
Summary: As a reductive Fe(II)-bearing mineral, green rust (GR) has the ability to adsorb and subsequently release TBP under anoxic conditions. The iron (hydr)oxides derived from GR can generate hydroxyl radicals that oxidatively degrade TBP. Additionally, the oxidation of GR immediately forms magnetite, which activates dioxygen to produce hydroxyl radicals. This work provides important evidence on the fate and transformation of TBP in redox alternating subsurface environments.
