Article
Environmental Sciences
Mingjing Zeng, Yu Zeng, Binchao Zhang, Yuanyuan Cheng, Bei Long, Junfeng Wu, Shuai Ren, Yong Liu
Summary: The performance of endogenous/exogenous nitrification and denitrification in treating inorganic wastewater with high ammonia nitrogen concentration was investigated. It was found that the addition of external carbon sources improved the adaptability of aerobic granules and increased the removal efficiency of total inorganic nitrogen (TIN). The coupling of endogenous/exogenous nitrification and denitrification reduced the consumption of aeration, saved external carbon source dosage, and decreased alkalinity consumption. This study provides an alternative option for treating wastewater from ionic rare earth mines.
ENVIRONMENTAL TECHNOLOGY
(2023)
Article
Biotechnology & Applied Microbiology
Paula Bucci, Bibiana Coppotelli, Irma Morelli, Noemi Zaritzky, Alejandro Caravelli
Summary: Several nitrogen transformation processes were studied in wastewater treatment, with a focus on heterotrophic nitrification-aerobic denitrification (HNAD) which was found to be more efficient when driven by intracellular carbon reserves. High abundance of HNAD bacteria and aerobic denitrifiers were detected using next generation sequencing (NGS) technology.
INTERNATIONAL BIODETERIORATION & BIODEGRADATION
(2021)
Article
Environmental Sciences
Huoqing Wang, Jia Miao, Yuepeng Sun
Summary: This study compared nitrogen removal and N2O emissions from lab-scale anoxic/aerobic sequencing batch reactor (AOSBR) and intermittent aeration sequencing batch reactor (IASBR), finding that IASBR showed enhanced nitrogen removal efficiency and lower N2O emission factors compared to AOSBR. N2O emissions were significantly higher during simultaneous nitrification and denitrification (SND) compared to aerobic nitrification and denitrification, with different emission factors for oxidized ammonium in each phase.
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
Engineering, Environmental
Paula Bucci, Bibiana Coppotelli, Irma Morelli, Noemi Zaritzky, Alejandro Caravelli
Summary: This study investigated the effects of different COD/N ratios and the addition of micronutrients on granule size and simultaneous nitrification-denitrification (SND) in a laboratory-scale aerobic SBR system. The results showed that small-size granules could be developed at the appropriate COD/TKN ratio with micronutrients, leading to better removal of inorganic nitrogen. However, without micronutrients and at a lower COD/TKN ratio, larger granules with lower removal efficiency were observed.
JOURNAL OF WATER PROCESS ENGINEERING
(2022)
Article
Environmental Sciences
Rui Yang, Lin-jiang Yuan, Ru Wang, Zhi-xian He, Lin Lei, Yan-chen Ma
Summary: This study investigates the production process of nitrous oxide (N2O) in the aerobic zone of nitrogen bio-removal process by measuring the activities of two key denitrifying enzymes. The results demonstrate that most of the N2O released and produced come from autotrophic denitrification, while heterotrophic denitrification acts as an N2O consumer. The study suggests that reducing autotrophic denitrification is the best way to reduce N2O production in the aerobic phase.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
(2022)
Article
Environmental Sciences
Dongyue Li, Wei Guo, Dongbo Liang, Jing Zhang, Jun Li, Peilin Li, Yaodong Wu, Xueying Bian, Fan Ding
Summary: This study examined the feasibility of using the SNEDPR-AGSBR process for treating low C/N ratio domestic sewage. The results showed that the rapid start-up and advanced nutrient removal were successfully achieved by selecting slow-growing organisms. The SNEDPR-AGSBR process demonstrated high removal efficiencies for nitrogen and phosphorus, indicating its potential for treating low C/N ratio domestic sewage.
ENVIRONMENTAL RESEARCH
(2022)
Article
Environmental Sciences
Shannon K. Cavanaugh, Bao Nguyen Quoc, Eron Jacobson, Robert Bucher, Pardi Sukapanpotharam, Mari-Karoliina H. Winkler
Summary: This study investigates the impact of dissolved oxygen and nitrite concentrations on nitrous oxide (N2O) emissions in wastewater treatment and provides strategies for meeting potential gaseous emission permits. The results show that higher dissolved oxygen and nitrite concentrations are associated with higher N2O emissions, and the lowest emissions are observed at a dissolved oxygen concentration of 1 mg L-1.
Article
Environmental Sciences
Denghui Chen, Haibo Li, Xiaofei Xue, Lili Zhang, Yanan Hou, Han Chen, Yousuo Zhang, Yunda Song, Shiqi Zhao, Jianbo Guo
Summary: The AGS-SPNDPR process showed successful cultivation of aerobic granular sludge for simultaneous partial nitrification, denitrification and phosphorus removal in low strength and low COD/TN ratio municipal wastewater. The tapered aeration method achieved excellent removal performance of COD and NH4+-N, and higher TN removal efficiency. Additionally, the process allowed for efficient phosphorus removal and enrichment of denitrifying glycogen-accumulating organisms, ammonia-oxidizing bacteria, and phosphorus-accumulating organisms.
ENVIRONMENTAL RESEARCH
(2022)
Article
Engineering, Environmental
Reynel Martinez Castellanos, Jasmim Muniz Rodrigues Dias, Isabelli Dias Bassin, Marcia Dezotti, Joao Paulo Bassin
Summary: The study found that SRT did not affect the stability of COD removal, but did impact phosphate removal, with lower SRT facilitating biological phosphate removal.
PROCESS SAFETY AND ENVIRONMENTAL PROTECTION
(2021)
Article
Engineering, Environmental
Edward J. H. van Dijk, Mark C. M. van Loosdrecht, Mario Pronk
Summary: The study found that the average emission factor of nitrous oxides is influenced by factors such as season, temperature, and rainfall, and different process controls may be necessary at different temperatures to ensure consistent low emissions.
Article
Agricultural Engineering
Qinghong Wang, Jiawen Kong, Jiahao Liang, Mohamed Gamal El-Din, Peng Zhao, Wenyu Xie, Chunmao Chen
Summary: The bioaugmentation potential of aerobic granular sludge (AGS) was explored for improved nitrogen removal in petroleum wastewater treatment. A highly efficient heterotrophic nitrification-aerobic denitrification (HN-AD) bacterial consortium was constructed and used to bioaugment the AGS, resulting in enhanced nitrogen removal. The addition of the immobilized consortium facilitated the formation of larger AGS particles and increased the gene abundance related to heterotrophic nitrification.
BIORESOURCE TECHNOLOGY
(2022)
Article
Soil Science
Nadine Loick, Elizabeth Dixon, G. Peter Matthews, Christoph Mueller, Veronica S. Ciganda, Maria Lopez-Aizpun, Miguel A. Repullo, Laura M. Cardenas
Summary: This study quantifies the production and consumption pathways of N2O in soil using labelled substrate-N, showing the impact of different water filled pore space on N-transformation processes and emissions. The research highlights the importance of heterotrophic nitrification and denitrification in the N2O emissions, demonstrating the complex relationship between water filled pore space and nitrogen transformations.
Article
Environmental Sciences
Junkai Zhao, Jianqiang Zhao, Wenjuan Yang, Bo Hu, Ting Huang, Shuting Xie, Shuhan Lei, Wei Hou
Summary: This study analyzed the impact of hydroxylamine (NH2OH) on the production of NO and N2O by nitrifying bacteria in activated sludge reactors. The results showed that the presence of NH2OH was positively correlated with dissolved oxygen levels and led to an imbalance in NH4+ oxidation, resulting in increased NO and N2O production under high DO conditions. Furthermore, the coexistence of NO2- and NH2OH in the reactor contributed to a significant generation of NO and N2O through both biotic/abiotic hybrid pathways and heterotrophic denitrification pathway.
JOURNAL OF ENVIRONMENTAL MANAGEMENT
(2022)
Article
Engineering, Environmental
Xueping Tian, Jingtao Zhao, Jun Huang, Guoke Chen, Yonggui Zhao
Summary: The metabolic process of aerobic granular sludge (AGS) treating piggery wastewater with high concentrations of carbon and nitrogen was elucidated through a combined analysis of microbial community, denitrification genes, and mathematical model calculations. The dominant microorganisms in AGS had potentials of various metabolic activities, with aerobic denitrification process being dominant. The study also revealed the resistance of rapid organic substrates storage in AGS during feast phase against high strength wastewater, providing carbon and energy sources in the famine phase.
JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING
(2021)
Article
Engineering, Environmental
Rong-Gui Zhu, Chang-Gui Pan, Feng-Jiao Peng, Chao-Yang Zhou, Jun-Jie Hu, Kefu Yu
Summary: This comprehensive survey investigated the occurrence, bioaccumulation, and trophic magnification of parabens and their metabolite 4-HB in a marine food web. Results showed that parabens were the predominant pollutants in marine organisms, with significant bioaccumulation from sediments. The estimated trophic magnification factor indicated biomagnification for MeP and trophic dilution for 4-HB. Overall, the risks for humans consuming marine organisms were found to be low.
Article
Engineering, Environmental
Andres F. Torres-Franco, Deborah Leroy-Freitas, Cristina Martinez-Fraile, Elisa Rodriguez, Pedro A. Garcia-Encina, Raul Munoz
Summary: Anaerobic and microalgae-based technologies have emerged as sustainable alternatives for municipal wastewater treatment. However, the presence of viruses in the treated wastewater is a major concern for reuse applications. This study assessed the ability of these technologies to reduce viruses during secondary wastewater treatment. The results showed that all technologies were effective in reducing the concentration of viruses, with microalgae-based treatment exhibiting the highest potential for reducing the disinfection requirements of treated wastewater.
Article
Engineering, Environmental
Young Gwang Kim, Sae Yun Kwon, Spencer J. Washburn, Scott C. Brooks, Ji Won Yoon, Lucien Besnard
Summary: The study uses Hg isotope ratios to identify the sources and exposure pathways of mercury in bivalves, finding that dissolved Hg phases in the water column are the primary source and exposure pathway to bivalves. This provides new insights into using bivalves as bioindicators for sediment quality monitoring.
Article
Engineering, Environmental
Hui Geng, Ying Xu, Rui Liu, Dianhai Yang, Xiaohu Dai
Summary: This study investigates the effect of cation exchange resin (CER) on the sequential recovery of hydrogen and methane from anaerobic digestion (AD) and the corresponding mechanisms. The results show that CER can simultaneously enhance the production of hydrogen and methane by promoting the solubilisation, hydrolysis, and acidification of organic matter. Additionally, CER facilitates effective contact between bacteria and organic particulates and reduces the energy barrier for mass transfer during methane production. The study also reveals changes in the microbial community structure and metagenomics during the AD process.
Article
Engineering, Environmental
Xiaojing Lin, Zhan Jin, Shunfeng Jiang, Zhiquan Wang, Suqing Wu, Ke Bei, Min Zhao, Xiangyong Zheng
Summary: Dehumidification combined with addition of absorbent resin supplement (ARS) was used to achieve rapid evaporation of non-pretreated urine, resulting in high water evaporation efficiency and nutrient recovery.
Article
Engineering, Environmental
Yangli Che, Chaoran Lin, Shen Li, Jiao Liu, Longhai Zhu, Shilei Yu, Nan Wang, Haoshuai Li, Mutai Bao, Yang Zhou, Tonghao Si, Rui Bao
Summary: Hydrodynamic processes play a crucial role in the transmission of sediments, microbial assembly, and organic carbon redistribution in the ocean. Through experiments and analysis, we found that hydrodynamics shape the assembly of microbial communities and control the redistribution of different sourced organic carbon, thereby influencing microbial-mediated biogeochemical transformation.
Article
Engineering, Environmental
Chao Chen, Yu Yang, Nigel J. D. Graham, Zhenyu Li, Xingtao Yang, Zhining Wang, Nadia Farhat, Johannes S. Vrouwenvelder, Li -an Hou
Summary: The fouling of seawater reverse osmosis membranes is a persistent challenge in desalination. This study monitored the operational performance of a desalination plant for 7 years and the fouling development in different areas of membrane modules. The findings showed that operational performance declined over time and fouling mainly occurred at the feed side of the modules, with the highest microbial diversity. Keystone species like Chloroflexi and Planctomycetes played an important role in maintaining community structure and biofilm maturation. Polysaccharides, soluble microbial products, marine humic acid-like substances, and inorganic substances contributed to fouling. Overall, biofouling had a significant impact on membrane fouling after 7 years of operation.
Article
Engineering, Environmental
Dan Li, Jieyi Sun, Yibo Fu, Wentao Hong, Heli Wang, Qian Yang, Junhong Wu, Sen Yang, Jianhui Xu, Yunfei Zhang, Yirong Deng, Yin Zhong, Ping'an Peng
Summary: Sulfidation-oxidation treatment of magnetite (Fe3O4) enhances the production of dark center dot OH, which can efficiently degrade dissolved organic matter (DOM) and accelerate carbon cycling.
Article
Engineering, Environmental
Cheng Yu, Kaijun Wang, Kaiyuan Zhang, Ruiyang Liu, Pingping Zheng
Summary: This study implemented a microaerobic-aerobic configuration in a full-scale municipal wastewater treatment facility and investigated the effects on sludge characteristics, pollutant removal, microbial community, and granulation mechanisms. The results showed successful transition from flocculent-activated sludge to well-defined AGS after two months of operation. The primary pathways for pollutant removal were simultaneous nitrification, denitrification, and phosphorus removal. Moreover, the incorporation of internal separators induced shifts in the flow pattern, which promoted granulation.
Article
Engineering, Environmental
Zhe Zhang, Shaoyang Hu, Guangrong Sun, Wei Wang
Summary: Halogenated aromatic disinfection byproducts (DBPs), such as halogenated phenols, have garnered widespread attention due to their high toxicity and prevalence. This study reports on the analysis, occurrence, and cytotoxicity of a group of emerging halogenated aromatic DBPs, known as halogenated polyhydroxyphenols (HPPs), in drinking water.
Article
Engineering, Environmental
Shengyue Chen, Jinliang Huang, Peng Wang, Xi Tang, Zhenyu Zhang
Summary: Accurate prediction of river water quality is crucial for sustainable water management. This study introduces wavelet analysis and transfer learning techniques to assist LSTM modeling, proposing a newly coupled modeling approach that improves short-term prediction of river water quality.
Article
Engineering, Environmental
Bang Du, Xinmin Zhan, Piet N. L. Lens, Yifeng Zhang, Guangxue Wu
Summary: Efficient anaerobic digestion relies on the cooperation of different microorganisms with different metabolic pathways. This study investigated the effects of different operational modes and the addition of powdered activated carbon (PAC) on ethanol metabolic pathways. The results showed that the SBR mode and the presence of CO2 facilitated ethanol metabolism towards propionate production, while the CFR mode with extended solids retention time enriched Geobacter. Adjusting operational modes and PAC addition can modulate anaerobic ethanol metabolism and enrich Geobacter.
Article
Engineering, Environmental
Wanfa Wang, Si-Liang Li, Jun Zhong, Yuanbi Yi, Fujun Yue, Zenglei Han, Qixin Wu, Ding He, Cong-Qiang Liu
Summary: This study compares the carbon biogeochemical processes in karst and non-karst regions within large thermal stratified river-reservoir systems. The results demonstrate that karst reservoirs have a reduced potential for carbon emissions and highlight the importance of considering geologic settings to improve accuracy in regional and global CO2 emission estimates.
Article
Engineering, Environmental
Chunxia Jiang, Zelong Zhao, Dong Zhu, Xiong Pan, Yuyi Yang
Summary: This study analyzed the occurrence and distribution of antibiotic resistance genes (ARGs) in different environmental media of the Yangtze River using metagenomics. Core resistome dominated by multidrug resistance genes was found in all samples, while rare resistome dominated by various resistance genes was more prevalent in plasmids. Specific bacteria were identified as hosts for both core and rare resistomes, with high clinical concern ARGs found in the rare resistome. Particle-associated environment provided the most ideal conditions for resistome hosts. This study provided insights into the genetic locations of ARGs and the community assembly mechanisms of ARG hosts in freshwater environments.
Article
Engineering, Environmental
Yu Zhang, Yongtao He, Linchun Jia, Lei Xu, Zheng Wang, Yueling He, Ling Xiong, Xumeng Lin, Hong Chen, Gang Xue
Summary: By synergizing organic carbon source, thiosulfate, and zero-valent iron, efficient mixotrophic denitrification of oligotrophic secondary effluent can be achieved. Thiosulfate plays a vital role in promoting TN removal efficiency, while corrosion of Fe0 releases OH- to neutralize H+ from thiosulfate-driven denitrification, creating a suitable environment for denitrification. The coordination of thiosulfate and Fe0 maintains the dominance of Thiobacillus for denitrification.