Article
Environmental Sciences
Lin Wang, Bingrong Li, Yongmei Li, Jianmin Wang
Summary: The study found that specific nitrification and denitrification rates increased under low dissolved oxygen conditions, with a decrease in the oxygen half saturation constant for both ammonia oxidizing bacteria and nitrite oxidizing bacteria. The observed yield coefficients also increased, along with higher relative abundances of AOB, NOB, and denitrifiers detected through high-throughput sequencing. Improved simultaneous nitrification and denitrification under low DO conditions contributed to enhanced nitrogen removal.
Article
Energy & Fuels
Awet Arefe Tesfahunegn, Xinshan Song, Yuhui Wang, Zhihao Si, Kahsay Gebresilassie Abraha, Libargachew Demlie Mihretu
Summary: This study focuses on developing a novel anode material for Microbial Fuel Cells (MFCs) that can effectively remove various pollutants while generating bioelectricity. The results show impressive removal rates of total inorganic nitrogen and high-power output and current density. This highlights the potential of this material for contaminant removal and energy generation, making it a promising method for purifying eutrophic water bodies.
CHEMICAL ENGINEERING AND PROCESSING-PROCESS INTENSIFICATION
(2023)
Review
Engineering, Environmental
Deepti Negi, Shelly Verma, Swati Singh, Achlesh Daverey, Jih-Gaw Lin
Summary: Constructed wetland is a sustainable eco-technology for remediation of contaminants, but its nitrogen removal efficiency is unsatisfactory. Anammox, an eco-friendly technology, can be integrated into constructed wetlands to overcome the shortcomings.
CHEMICAL ENGINEERING JOURNAL
(2022)
Article
Engineering, Environmental
Kewei Liao, Sijia Ma, Caifeng Liu, Haidong Hu, Jinfeng Wang, Bing Wu, Hongqiang Ren
Summary: This study investigated the effects of low dissolved oxygen (DO) levels on dissolved organic nitrogen (DON) and N-nitrosodimethylamine (NDMA) precursor concentrations in biological nutrient removal (BNR) effluents. Surprisingly, lower DO levels were found to result in significantly higher levels of effluent DON and NDMA precursors. Ultrahigh-resolution mass spectrometry analysis revealed that molecules produced by microbes at low-DO levels may play critical roles in NDMA formation. Path analysis suggested that NDMA formation potential had strong associations with microbe-DON network stability.
Article
Environmental Sciences
Aryan Samadi, Azadeh Kermanshahi pour, Graham Gagnon
Summary: Bioelectrochemical degradation is an effective method for providing electron acceptor to microorganisms. This study developed a two-chamber bioelectrochemical reactor and investigated the potential for enhancing the degradation of 1,4-dioxane. The results showed that the degradation efficiency was improved by increasing dissolved oxygen concentration and microbial activity at low potentials.
ENVIRONMENTAL POLLUTION
(2023)
Article
Environmental Sciences
Ting Yang, Qian Hao, Yajie Qiao, Zhimin Fu
Summary: The research showed that low strength has a reversible inhibitory effect on the nitrogen removal performance in anammox reactors, mainly due to the increase of oxygen from low substrate concentration. Strict regulation of dissolved oxygen in the influent is deemed critical for achieving successful and stable operation under low strength conditions.
ENVIRONMENTAL TECHNOLOGY
(2022)
Article
Agricultural Engineering
Susan N. James, Arya Vijayanandan
Summary: An anoxic-aerobic-anoxic process was established in a sequencing batch reactor to simultaneously remove organic carbon and nitrogen from wastewater. The study found that the optimum conditions for the process were achieved with a dissolved oxygen level of 1.5 mg/L and 1 hour pre-anoxic and post-anoxic periods. Under these conditions, the removal efficiencies of TOC, NH4+-N, and TN were 98.76%, 98.52%, and 88.23% respectively. Breakpoints in the pH, DO, and ORP curves provided insights into the biochemical reactions occurring in the reactor. Inhibition studies revealed that nitrogen removal pathways such as heterotrophic nitrification or direct conversion contributed to the removal of 27.69% of NH4+-N, while aerobic denitrification accounted for the removal of 20.55% of TN. Microbial community analysis confirmed the presence of heterotrophic nitrifiers and aerobic denitrifiers. The study emphasized the benefits of the varied redox conditions provided by limited aeration for nitrogen removal, leading to reduced energy usage and operating costs.
BIORESOURCE TECHNOLOGY
(2022)
Article
Environmental Sciences
Hong Wang, Guanlong Yu, Weining He, Chunyan Du, Zhengyu Deng, Dongbo Wang, Min Yang, Enzhe Yang, Yaoyu Zhou, Eli Hendrik Sanjaya, Hong Chen
Summary: A novel dissolved oxygen-differentiated airlift internal circulation reactor was developed in this study to enhance autotrophic nitrogen removal efficiency from wastewater, achieving high total nitrogen removal efficiency of 80% within 30 days and stable maintenance over 200 days. The reactor optimized nitritation and anammox reactions, leading to enhanced ANR performance.
JOURNAL OF ENVIRONMENTAL MANAGEMENT
(2021)
Article
Environmental Sciences
Linlin Li, Jing Zhang, Qiuyue Shi, Shaoyong Lu
Summary: To compare the effect of different oxygen supply strategies on nitrogen removal in constructed wetlands, tidal flow constructed wetlands (TFCWs) and intermittently aerated constructed wetlands (IACWs) were investigated. Results showed that IACWs had high removal efficiencies for NH4+-N and COD, while TFCWs showed higher efficiency for total nitrogen removal due to enhanced nitrification and denitrification. The bacterial communities in TFCWs were enriched with key genera related to nitrogen transformation, while IACWs had a more complex and robust community structure.
Article
Microbiology
Min Cai, Yiguo Hong, Jiapeng Wu, Selina Sterup Moore, Teofilo Vamerali, Fei Ye, Yu Wang
Summary: This study investigated the effects of NO3-, NH4+, dissolved oxygen (DO), and organic C on microbial nitrogen removal in pond sediments using slurry incubation experiments and N-15 tracer techniques. The addition of NO3- significantly promoted denitrification rates, while elevated DO concentrations inhibited denitrification. Organic C increased denitrification rates, but had little influence on nitrogen removal due to abundant NH4+ in pond sediments.
Article
Chemistry, Physical
Domenico Borello, Gabriele Gagliardi, Giorgia Aimola, Valeria Ancona, Paola Grenni, Giuseppe Bagnuolo, Gian Luigi Garbini, Ludovica Rolando, Anna Barra Caracciolo
Summary: The study showed that using terrestrial Microbial Fuel Cells (MFC) can effectively promote the removal of DDE from soil, and adding compost can stimulate microbial activity and improve MFC performance.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2021)
Article
Agricultural Engineering
Ziang Kong, Han Wang, Guoliang Yan, Qun Yan, Jung Rae Kim
Summary: The effects of limited dissolved oxygen (DO) on hydrogenotrophic denitrification at biocathode were investigated using a bioelectrochemical system. It was found that total nitrogen removal increased by 5.9% when DO reached about 0.24 mg/L with the cathodic chamber unplugged (group R_Exposure). The presence of limited DO not only influenced the nitrogen metabolic pathway, but also enriched the composition of microbial communities of ammonia-oxidizing bacteria and nitrite-oxidizing bacteria accordingly.
BIORESOURCE TECHNOLOGY
(2023)
Article
Engineering, Environmental
Luling Tian, Kuanliang Feng, Ganghua Qin, Xiaozhong Tong, Xiangdong Feng, Xiangyang Xu, Liang Zhu
Summary: This study investigates the impact of aerator position on the distribution and stability of dissolved oxygen in aerobic granular sludge (AGS). The results suggest that placing the aerator at 1/6 height of the reactor improves sludge settling behavior and structural stability, resulting in higher total nitrogen removal efficiency and lower energy consumption.
JOURNAL OF WATER PROCESS ENGINEERING
(2022)
Article
Engineering, Environmental
Yeunook Bae, Nyssa M. Crompton, Neha Sharma, Yihang Yuan, Jeffrey G. Catalano, Daniel E. Giammar
Summary: The removal of dissolved selenium from wastewater is a challenging issue for industries, and iron electrocoagulation has been found to effectively remove selenate and selenite. The rate and extent of dissolved selenium removal was highest at pH 8 and strictly anoxic conditions, with green rust and ferrous hydroxide playing important roles. Further research is needed to optimize iron electrocoagulation for selenium removal.
Article
Agricultural Engineering
Yunguang Ma, Weiqing Jiang, Zebing Nie, Peng Qi, Yang Jiao, Jiaxi Peng, Dejun Bian
Summary: This study investigated the mechanisms of enhanced biological nitrogen and phosphorus removal in a Micro-pressure swirl reactor (MPSR). The results showed that denitrifying phosphate accumulating organisms (DPAOs) had high activity in both low dissolved oxygen and high dissolved oxygen zones. Flavobacterium and Dechloromonas were found to dominate the denitrification phosphorus removal (DPR) process in the low dissolved oxygen zone. The integration of nutrient removal pathways within MPSR was also revealed.
BIORESOURCE TECHNOLOGY
(2022)