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Gao R, Jin H, Han M, Lou J. Iron-mediated DAMO-anammox process: Revealing the mechanism of electron transfer. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 356:120750. [PMID: 38520849 DOI: 10.1016/j.jenvman.2024.120750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 03/17/2024] [Accepted: 03/20/2024] [Indexed: 03/25/2024]
Abstract
The nitrate denitrifying anaerobic methane oxidation-anaerobic ammonia oxidation (DAMO-anammox) can accomplish nitrogen removal and methane (CH4) reduction. This process greatly contributes to carbon emission mitigation and carbon neutrality. In this study, we investigated the electron transfer process of functional microorganisms in the iron-mediated DAMO-anammox system. Fe3+ could be bound to several functional groups (-CH3, COO-, -CH) in extracellular polymeric substance (EPS), and the functional groups bound were different at different iron concentration. Fe3+ underwent reduction reactions to produce Fe2+. Most Fe3+ and Fe2+ react with microorganisms and formed chelates with EPS. Three-dimensional fluorescence spectra showed that Fe3+ affected the secretion of tyrosine and tryptophan, which were essential for cytochrome synthesis. The presence of Fe3+ accelerated c-type cytochrome-mediated extracellular electron transfer (EET), and when more Fe3+ existed, the more cytochrome C expressed. DAMO archaea (M. nitroreducens) in the system exhibited a high positive correlation with the functional genes (resa and ccda) for cytochrome c synthesis. Some denitrifying microorganisms showed positive correlations with the abundance of riboflavin. This finding showed that riboflavin secreted by functional microorganisms acted as an electron shuttle. In addition, DAMO archaea were positively correlated with the hair synthesis gene pily1, which indicated that direct interspecies electron transfer (DIET) may exist in the iron-mediated DAMO-anammox system.
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Affiliation(s)
- Ran Gao
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou, 310012, China.
| | - Hao Jin
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou, 310012, China.
| | - Mengru Han
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou, 310012, China.
| | - Juqing Lou
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou, 310012, China.
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2
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Jia X, Wang Y, Zhao M, Zhang F, Li C, Ma D. Migration and morphological transformation patterns of heavy metals on sludge cells and extracellular polymeric substances (EPS) under the influence of different treatments. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024; 31:21578-21590. [PMID: 38393566 DOI: 10.1007/s11356-024-32398-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Accepted: 02/03/2024] [Indexed: 02/25/2024]
Abstract
The impediment of sludge resource utilization stems from the presence of heavy metals within the sludge matrix. To optimize heavy metal removal techniques from undried sludge, it is essential to study the distribution of heavy metals in the sludge flocs structure and the changes in morphology in the sludge cells after different treatments. In this study, the sludge was subjected to chemical treatments using citric acid (CA), EDTA, and saponin, as well as electrokinetic treatment at 2 V/cm. The distribution and migration of Cu, Ni, and Zn in sludge flocs after various treatment methods were analyzed. The heavy metals were found to migrate from intracellular to extracellular polymeric substances (EPS) without causing extensive sludge cell lysis. They gradually diffused outward with the dispersion of the EPS layer. The migration efficiency of the three heavy metals in the sludge flocs was Zn, Ni, and Cu. This was mainly related to the initial distribution and morphology of the heavy metals. Under the influence of chemicals and an electric field, the acid-soluble and reducible heavy metals in the cells partially migrated to the EPS, while the stable heavy metals transformed into an unstable state. Furthermore, the order of chemical reagents in terms of their effect on the migration efficiency of heavy metals was CA > EDTA > Saponin, owing to the varying binding strengths of heavy metals and their impact on the degree of loosening of the EPS. Especially after CA treatment a greater proportion of Cu, Ni, and Zn were transferred from the cells to the EPS. The acidification effect near the anode during electrokinetic treatment intensifies the migration of heavy metals. This study provides basic research for subsequent engineering optimization aimed at removing heavy metals from sludge.
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Affiliation(s)
- Xiaoyu Jia
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300350, China
| | - Yuxin Wang
- Lianhe Equator Environmental Impact Assessment Co Ltd, Tianjin, 300350, People's Republic of China
| | - Miaomiao Zhao
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300350, China
| | - Fan Zhang
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300350, China
| | - Chen Li
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300350, China
| | - Degang Ma
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300350, China.
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3
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Du X, Hong M, Yang Y, Li J, Su Y, Liu N. Removal mechanisms of aqueous Cr(VI) by anaerobic fermentation sludge. ENVIRONMENTAL TECHNOLOGY 2023; 44:3975-3987. [PMID: 35549986 DOI: 10.1080/09593330.2022.2077136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
After fermentation, activated sludge contains many acid-producing bacteria and their metabolites, which have a good reducing effect. Various active groups (e.g., hydroxyl, amino, carboxyl, and phosphate) on microbial cell surfaces can adsorb heavy metals through complexation or chelation, forming heavy metal precipitates and thereby reducing the toxicity of heavy metals. However, the effects and mechanisms of using sludge after anaerobic fermentation to remove Cr(VI) are unclear, such as the dominance of direct versus indirect biological reduction, the contribution of abiotic effects, and the influence of fermentation conditions. This paper compares Cr(VI) removal in fermented and unfermented sludges. After fermentation for 24 h, 99.9% of the Cr(VI) (50 mg/L) in anaerobic sludge was removed within 7 h, which was twice the rate in unfermented activated sludge. A series of comparative experiments demonstrated that Cr(VI) removal primarily occurred through biological effects (about 92%), which included biological reduction and biosorption. 16SrRNA gene sequencing revealed that Cr(VI) transformation primarily occurred through direct biological reduction, with the related genera being Trichococcus, Acetobacter, Aeromonas, and Tolumonas. Fourier-transform infrared (FTIR) spectroscopy results showed that the C = O and C-O functionalities on sludge were likely involved in the Cr(VI) conversion. Majority of the Cr(VI) in the system was reduced to Cr(III) and existed in the suspension, with a small amount deposited on the sludge surface. The X-ray photoelectron spectroscopy (XPS) results indicated that the majority of Cr was present as reduced Cr(III) on the sludge. These results demonstrate that after fermentation in an aqueous environment, activated sludge is an effective medium for the remediation of Cr(VI). These results are useful for designing a green and sustainable bioreduction system for the remediation of Cr(VI)-polluted water.
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Affiliation(s)
- Xiaoyan Du
- Key Laboratory of Groundwater Resources and Environment, Ministry of Education, College of Environment and Resources, Jilin University, Changchun, People's Republic of China
| | - Mei Hong
- Key Laboratory of Groundwater Resources and Environment, Ministry of Education, College of Environment and Resources, Jilin University, Changchun, People's Republic of China
| | - Yadong Yang
- Key Laboratory of Groundwater Resources and Environment, Ministry of Education, College of Environment and Resources, Jilin University, Changchun, People's Republic of China
| | - Jing Li
- Key Laboratory of Groundwater Resources and Environment, Ministry of Education, College of Environment and Resources, Jilin University, Changchun, People's Republic of China
| | - Yaoming Su
- South China Institute of Environmental Sciences, MEP, People's Republic of China
| | - Na Liu
- Key Laboratory of Groundwater Resources and Environment, Ministry of Education, College of Environment and Resources, Jilin University, Changchun, People's Republic of China
- Institute of Groundwater and Earth Science, Jinan University, Guangzhou City, People's Republic of China
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4
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Xu X, Li H, Guo M, Zeng M, Liu W, Wu N, Liang J, Cao J. Deciphering performance and potential mechanism of anammox-based nitrogen removal process responding to nanoparticulate and ionic forms of different heavy metals through big data analysis. Sep Purif Technol 2022. [DOI: 10.1016/j.seppur.2022.122044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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5
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Yuan H, Huang Y, Jiang O, Huang Y, Qiu D, Gustave W, Tang X, Li Z. Removal of Arsenate From Groundwater by Cathode of Bioelectrochemical System Through Microbial Electrosorption, Reduction, and Sulfuration. Front Microbiol 2022; 13:812991. [PMID: 35359725 PMCID: PMC8963459 DOI: 10.3389/fmicb.2022.812991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 01/31/2022] [Indexed: 11/17/2022] Open
Abstract
Arsenate [As(V)] is a toxic metalloid and has been observed at high concentrations in groundwater globally. In this study, a bioelectrochemical system (BES) was used to efficiently remove As(V) from groundwater, and the mechanisms involved were systematically investigated. Our results showed that As(V) can be efficiently removed in the BES cathode chamber. When a constant cell current of 30 mA (Icell, volume current density = 66.7 A/m3) was applied, 90 ± 3% of total As was removed at neutral pH (7.20–7.50). However, when Icell was absent, the total As in the effluent, mainly As(V), had increased approximately 2–3 times of the As(V) in influent. In the abiotic control reactor, under the same condition, no significant total As or As(V) removal was observed. These results suggest that As(V) removal was mainly ascribed to microbial electrosorption of As(V) in sludge. Moreover, part of As(V) was bioelectrochemically reduced to As(III), and sulfate was also reduced to sulfides [S(–II)] in sludge. The XANES results revealed that the produced As(III) reacted with S(–II) to form As2S3, and the residual As(III) was microbially electroadsorbed in sludge. This BES-based technology requires no organic or chemical additive and has a high As(V) removal efficiency, making it an environment-friendly technique for the remediation of As-contaminated groundwater.
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Affiliation(s)
- Honghong Yuan
- Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, College of Environmental and Resource Sciences, Institute of Soil and Water Resources and Environmental Science, Zhejiang University, Hangzhou, China
- ZJU-Hangzhou Global Scientific and Technological Innovation Center, Hangzhou, China
| | - Yumeng Huang
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, Zhejiang University, Hangzhou, China
| | - Ouyuan Jiang
- Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, College of Environmental and Resource Sciences, Institute of Soil and Water Resources and Environmental Science, Zhejiang University, Hangzhou, China
| | - Yue Huang
- Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, College of Environmental and Resource Sciences, Institute of Soil and Water Resources and Environmental Science, Zhejiang University, Hangzhou, China
| | - Dongsheng Qiu
- Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, College of Environmental and Resource Sciences, Institute of Soil and Water Resources and Environmental Science, Zhejiang University, Hangzhou, China
| | - Williamson Gustave
- School of Chemistry, Environmental and Life Sciences, University of The Bahamas, Nassau, Bahamas
| | - Xianjin Tang
- Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, College of Environmental and Resource Sciences, Institute of Soil and Water Resources and Environmental Science, Zhejiang University, Hangzhou, China
- *Correspondence: Xianjin Tang,
| | - Zhongjian Li
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, Zhejiang University, Hangzhou, China
- Institute of Zhejiang University - Quzhou, Quzhou, China
- Zhongjian Li,
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6
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Liu Y, Han Y, Guo J, Zhang J, Hou Y, Song Y, Lu C, Li H, Zhong Y. New insights of simultaneous partial nitritation, anammox and denitrification (SNAD) system to Zn(II) exposure: Focus on affecting the regulation of quorum sensing on extracellular electron transfer and microbial metabolism. BIORESOURCE TECHNOLOGY 2022; 346:126602. [PMID: 34953995 DOI: 10.1016/j.biortech.2021.126602] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 12/13/2021] [Accepted: 12/17/2021] [Indexed: 06/14/2023]
Abstract
Here, the toxicity responses mechanism of the simultaneous partial nitritation, anammox and denitrification (SNAD) system to Zn(II) exposure were explored with emphasis on the repressed quorum sensing (QS) regulation on extracellular electron transfer and microbial metabolism. Results showed that Zn(II) accumulated in cells and induced oxidative stress, which led to microbial structure destruction. The increased electron transfer impedance and reduced redox substances (flavin/Cytochrome c) implied that Zn(II) affected electron transfer. The decreased ATP level, dehydrogenase and nitrogen related enzymatic activities showed Zn(II) affected organic matter and nitrogen metabolism. Furthermore, combined with Pearson network analysis, Zn(II) exposure disturbed the QS to decrease Acyl Homoserine Lactones (AHLs) secretion responsible for regulating extracellular electron transfer and microbial metabolism, thereby disturbing the performance of the SNAD system. This study provided new insights into the toxicity responses mechanism of the SNAD system to HM exposure.
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Affiliation(s)
- Yinuo Liu
- School of Environmental and Municipal Engineering, Tianjin Key Laboratory of Aquatic Science and Technology, Tianjin Chengjian University, Tianjin 300384, China
| | - Yi Han
- School of Environmental and Municipal Engineering, Tianjin Key Laboratory of Aquatic Science and Technology, Tianjin Chengjian University, Tianjin 300384, China.
| | - Jianbo Guo
- School of Civil Engineering and Architecture, Taizhou University, Taizhou 318000, Zhejiang, China; School of Environmental and Municipal Engineering, Tianjin Key Laboratory of Aquatic Science and Technology, Tianjin Chengjian University, Tianjin 300384, China.
| | - Jianbing Zhang
- Tianjin Municipal Engineering Design & Research Institute Co.,Ltd., Tianjin 300051, China
| | - Yanan Hou
- School of Environmental and Municipal Engineering, Tianjin Key Laboratory of Aquatic Science and Technology, Tianjin Chengjian University, Tianjin 300384, China
| | - Yuanyuan Song
- School of Environmental and Municipal Engineering, Tianjin Key Laboratory of Aquatic Science and Technology, Tianjin Chengjian University, Tianjin 300384, China
| | - Caicai Lu
- School of Environmental and Municipal Engineering, Tianjin Key Laboratory of Aquatic Science and Technology, Tianjin Chengjian University, Tianjin 300384, China
| | - Haibo Li
- School of Environmental and Municipal Engineering, Tianjin Key Laboratory of Aquatic Science and Technology, Tianjin Chengjian University, Tianjin 300384, China
| | - Yuan Zhong
- School of Environmental and Municipal Engineering, Tianjin Key Laboratory of Aquatic Science and Technology, Tianjin Chengjian University, Tianjin 300384, China
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7
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Li Y, Xin M, Xie D, Fan S, Ma J, Liu K, Yu F. Variation in Extracellular Polymeric Substances from Enterobacter sp. and Their Pb 2+ Adsorption Behaviors. ACS OMEGA 2021; 6:9617-9628. [PMID: 33869942 PMCID: PMC8047720 DOI: 10.1021/acsomega.1c00185] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 03/25/2021] [Indexed: 05/15/2023]
Abstract
The objective of this study was to investigate the effects of the cultivation time, temperature, and pH value on the yield and composition of extracellular polymeric substances (EPS) from Enterobacter sp. FM-1 (FM-1) and to analyze the Pb2+ adsorption behavior of soluble EPS (S-EPS), loosely bound EPS (LB-EPS), and tightly bound EPS (TB-EPS). Maximum EPS production was obtained when the cultivation time, temperature, and pH value were 24 h, 30 °C, and 8.0, respectively. The main components of EPS were proteins, polysaccharides, and nucleic acids, but the different EPS types contained different proportions and specific components. The Pb2+ adsorption capacity of LB-EPS was 2.23 and 1.50 times higher than that of S-EPS and TB-EPS, respectively. After Pb2+ adsorption by LB-EPS, the pH value of the reaction system decreased to the lowest of 5.23, which indicated that LB-EPS contained more functional groups that could release H+, which will help to better adsorb Pb2+ through ion exchange. The three-dimensional excitation-emission matrix fluorescence spectroscopy (3D-EEM) analysis showed that the fluorescence intensity of tryptophan-containing substances decreased by 85.5% after Pb2+ adsorption by LB-EPS, which indicated the complexation of tryptophan-containing substances with Pb2+. Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) O spectra indicated that the C=O peak from protein amide I of tryptophan-containing substances in LB-EPS was mainly responsible for the complexation of Pb2+. After the adsorption of Pb2+, the proportion of the C=O peak in LB-EPS increased by 33.89%, indicating that the complexation of LB-EPS with Pb2+ was mainly attributed to the O atom in the C=O terminus of protein amide I.
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Affiliation(s)
- Yi Li
- Key
Laboratory of Ecology of Rare and Endangered Species and Environmental
Protection (Guangxi Normal University), Ministry of Education, 541004 Guilin, China
- College
of Environment and Resources, Guangxi Normal
University, 541004 Guilin, China
- Innovation
Institute of Sustainable Development, Guangxi
Normal University, 541004 Guilin, China
| | - Meifen Xin
- College
of Environment and Resources, Guangxi Normal
University, 541004 Guilin, China
| | - Dongyu Xie
- College
of Environment and Resources, Guangxi Normal
University, 541004 Guilin, China
| | - Shirui Fan
- College
of Environment and Resources, Guangxi Normal
University, 541004 Guilin, China
| | - Jiangming Ma
- Key
Laboratory of Ecology of Rare and Endangered Species and Environmental
Protection (Guangxi Normal University), Ministry of Education, 541004 Guilin, China
- College
of Life Science, Guangxi Normal University, 541004 Guilin, China
- Innovation
Institute of Sustainable Development, Guangxi
Normal University, 541004 Guilin, China
| | - Kehui Liu
- Key
Laboratory of Ecology of Rare and Endangered Species and Environmental
Protection (Guangxi Normal University), Ministry of Education, 541004 Guilin, China
- College
of Life Science, Guangxi Normal University, 541004 Guilin, China
- Innovation
Institute of Sustainable Development, Guangxi
Normal University, 541004 Guilin, China
- . Tel.: +86 773 5845952
| | - Fangming Yu
- Key
Laboratory of Ecology of Rare and Endangered Species and Environmental
Protection (Guangxi Normal University), Ministry of Education, 541004 Guilin, China
- College
of Environment and Resources, Guangxi Normal
University, 541004 Guilin, China
- Innovation
Institute of Sustainable Development, Guangxi
Normal University, 541004 Guilin, China
- . Tel.: +86 773 5846141
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8
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Tang CJ, Zhang L, Feng F, Xiong L, Mahmood Q, Zeng W, Chai X, Wang Y. Long-term domestication to Mn stresses alleviates the inhibition on anammox process. WATER ENVIRONMENT RESEARCH : A RESEARCH PUBLICATION OF THE WATER ENVIRONMENT FEDERATION 2020; 92:1966-1974. [PMID: 32108974 DOI: 10.1002/wer.1316] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 02/16/2020] [Accepted: 02/22/2020] [Indexed: 06/10/2023]
Abstract
Heavy metals such as Mn2+ are common contaminants in ammonium-rich wastewater. The information of Mn2+ effect on anammox process needs further investigation. The short- and long-term effects of Mn2+ on anammox were explored by anammox granular sludge. Batch tests showed that the half inhibition value (IC50 ) of Mn2+ was 4.83 mg/L. The anammox activity was severely inhibited in 0.5 hr under 15 mg/L Mn2+ . However, after long-term domestication by increasing the concentration of Mn2+ , both the low-load reactor (R1) and the high-load reactor (R2) performed well, achieving volumetric nitrogen removal rate of 6.36 kg/(m3 ·d) and 13.99 kg/(m3 ·d), respectively. The average ammonium and nitrite removal efficiency of both reactors under 200 mg/L Mn still maintained above 90%. The results from long-term reactors' operation showed that the serious inhibition effect indicated by the batch test was significantly exaggerated. The granules became dispersed after long-term operation in the high-load reactor (R2) which might be correlated to the high osmotic pressure caused by high Mn2+ load, and the mechanism needs to be investigated further. PRACTITIONER POINTS: The half inhibition value of Mn2+ on anammox sludge was 4.83 mg/L in batch experiment. 200 mg/L Mn2+ did not cause any inhibition on anammox process during long-term operation. Granular sludge is finer under high nitrogen loads with 200 mg/L Mn stress.
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Affiliation(s)
- Chong-Jian Tang
- School of Metallurgy and Environment, Central South University, Changsha, China
- Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, Changsha, China
| | - Lin Zhang
- School of Metallurgy and Environment, Central South University, Changsha, China
- Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, Changsha, China
| | - Fan Feng
- School of Metallurgy and Environment, Central South University, Changsha, China
- Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, Changsha, China
| | - Lei Xiong
- School of Metallurgy and Environment, Central South University, Changsha, China
| | - Qaisar Mahmood
- Department of Environmental Sciences, COMSATS University Islamabad, Abbottabad Campus, Pakistan
| | - Weizhi Zeng
- School of Metallurgy and Environment, Central South University, Changsha, China
- Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, Changsha, China
| | - Xilin Chai
- School of Metallurgy and Environment, Central South University, Changsha, China
- Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, Changsha, China
| | - Yunyan Wang
- School of Metallurgy and Environment, Central South University, Changsha, China
- Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, Changsha, China
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9
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Feng F, Duan CS, Tang X, Chen X, Lu X, Chai XL, Mahmood Q, Tang CJ, Chai LY. Performance, microbial community and inhibition kinetics of long-term Cu 2+ stress on an air-lift nitritation reactor with self-recirculation. J Environ Sci (China) 2020; 91:117-127. [PMID: 32172960 DOI: 10.1016/j.jes.2020.01.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 01/22/2020] [Accepted: 01/26/2020] [Indexed: 05/12/2023]
Abstract
Biological nitrogen removal process could be affected due to the presence of heavy metals owing to their toxicity and accumulation in the sludge. In this study, the impact of Cu2+ shock on a long-term nitritation operation was investigated in an air-lift reactor with self-recirculation. Both the dynamics of microbial community and inhibition kinetics under Cu2+ stress were ascertained. The results showed that Cu2+ exerted severe inhibition on nitritation performance of an air-lift reactor (ALR) at 25 mg/L. The corresponding NH4+-N removal efficiency decreased to below 50%, which was mainly due to the variation of microbial community structure, especially the inhibition of nitrifiers like Nitrosomonas (the relative abundance decreased from 30% to 1% after Cu2+ inhibition). Kinetic parameters were obtained and compared after fitting the Haldane model. The long-term Cu2+ stress on the ALR aggravated the ammonium affinity and the resistance to substrate self-inhibition of the nitritation sludge, but reduced the resistance to Cu2+ inhibition. Furthermore, Cu2+ acted as uncompetitive inhibitor on nitritation process. Our results provide new insights into the nitritation characteristics under long-term Cu2+ stress.
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Affiliation(s)
- Fan Feng
- Department of Environmental Engineering, School of Metallurgy and Environment, Central South University, Changsha, 410083, China; National Engineering Research Centre for Control and Treatment of Heavy Metal Pollution, Changsha, 410083, China
| | - Cheng-Shan Duan
- Department of Environmental Engineering, School of Metallurgy and Environment, Central South University, Changsha, 410083, China; National Engineering Research Centre for Control and Treatment of Heavy Metal Pollution, Changsha, 410083, China
| | - Xi Tang
- Department of Environmental Engineering, School of Metallurgy and Environment, Central South University, Changsha, 410083, China; National Engineering Research Centre for Control and Treatment of Heavy Metal Pollution, Changsha, 410083, China
| | - Xi Chen
- Department of Environmental Engineering, School of Metallurgy and Environment, Central South University, Changsha, 410083, China; National Engineering Research Centre for Control and Treatment of Heavy Metal Pollution, Changsha, 410083, China
| | - Xuan Lu
- Department of Environmental Engineering, School of Metallurgy and Environment, Central South University, Changsha, 410083, China; National Engineering Research Centre for Control and Treatment of Heavy Metal Pollution, Changsha, 410083, China
| | - Xi-Lin Chai
- The Jiangxi Provincial Collaborative Research Institute for Environmental Protection Industry, Wannian, 335500, China; Jiangxi Gaia Environmental Science & Technology Co., Ltd., Shangrao, 334000, China
| | - Qaisar Mahmood
- Department of Environmental Sciences, COMSATS University, Abbottabad, Pakistan
| | - Chong-Jian Tang
- Department of Environmental Engineering, School of Metallurgy and Environment, Central South University, Changsha, 410083, China; National Engineering Research Centre for Control and Treatment of Heavy Metal Pollution, Changsha, 410083, China.
| | - Li-Yuan Chai
- Department of Environmental Engineering, School of Metallurgy and Environment, Central South University, Changsha, 410083, China; National Engineering Research Centre for Control and Treatment of Heavy Metal Pollution, Changsha, 410083, China
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10
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Li D, Xi H. Layered Extraction and Adsorption Performance of Extracellular Polymeric Substances from Activated Sludge in the Enhanced Biological Phosphorus Removal Process. Molecules 2019; 24:E3358. [PMID: 31527388 PMCID: PMC6767238 DOI: 10.3390/molecules24183358] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Revised: 09/11/2019] [Accepted: 09/12/2019] [Indexed: 01/16/2023] Open
Abstract
A large amount of phosphorus was found in the extracellular polymeric substances (EPS) of activated sludge used in enhanced biological phosphorus removal (EBPR), so the role of EPS and extracellular phosphorus in EBPR should not be neglected. The composition and properties of tightly bound EPS (TB-EPS) and loosely bound EPS (LB-EPS) were significantly different, and it was necessary to study the adsorption performance of EPS through the fractionating of activated sludge into LB-EPS, TB-EPS and microbial cells. In this study, the adsorption performance of LB-EPS and TB-EPS for phosphate was explored by extracting LB-EPS and TB-EPS via sonication and cation exchange resin (CER), respectively. The results indicated that the sonication-CER method was an efficient and reliable extraction method for EPS with a synergistic effect. The performance of EPS in the adsorption/complexing of phosphate was excellent because of its abundant functional groups. Specifically, the type and content of metal elements and functional groups in TB-EPS were much greater than those in LB-EPS, which led to the key role of TB-EPS in the adsorption/complexing of phosphate. Finally, a metabolic model for EBPR with consideration of the adsorption performance of LB-EPS and TB-EPS was proposed.
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Affiliation(s)
- Daxue Li
- State Key Laboratory of NBC Protection for Civilian, Beijing 102205, China.
- Department of Military Installations, Army Logistic University of PLA, Chongqing 401331, China.
| | - Hailing Xi
- State Key Laboratory of NBC Protection for Civilian, Beijing 102205, China.
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11
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Jiang CK, Tang X, Tan H, Feng F, Xu ZM, Mahmood Q, Zeng W, Min XB, Tang CJ. Effect of scrubbing by NaClO backwashing on membrane fouling in anammox MBR. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 670:149-157. [PMID: 30904641 DOI: 10.1016/j.scitotenv.2019.03.170] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 02/19/2019] [Accepted: 03/12/2019] [Indexed: 06/09/2023]
Abstract
NaClO based chemically enhanced backwash (CEB) is often administered to maintain membrane permeability during the operation of MBR. However, the effect and working mechanism of NaClO concentrations in CEB were rarely investigated. The current investigation examined the changes in membrane resistance, permeate production and membrane morphology with or without CEB in an anammox MBR to reveal the scrubbing effect of different NaClO concentrations (0-596 mg/L). Good cleaning effect indicated by membrane fouling rate of 1.98-2.26 kPa/day and membrane permeate production of 80-88 L was observed when NaClO concentration of 149-596 mg/L was used. The best cleaning effect was observed when 298 mg/L of NaClO was used. To explore the mechanism of CEB action, backwashing foulants were also analyzed. Insoluble EPS transformed into soluble forms like S-EPS or SMP after the sludge was exposed to NaClO. The NaClO based CEB removed 112-675 mg of polysaccharide (PS)/m2 in foulants at NaClO concentration of 149-596 mg/L, which was significantly higher than the value obtained by pure water (35 mg PS/m2). The possible mechanisms behind the detachment of soluble PS seemed as oxidation and sterilization by NaClO. The current investigation provides useful guidelines on NaClO concentrations applied during CEB for anammox MBR.
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Affiliation(s)
- Chu-Kuan Jiang
- School of Metallurgy and Environment, Central South University, Changsha 410083, China; Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, Changsha 410083, China
| | - Xi Tang
- School of Metallurgy and Environment, Central South University, Changsha 410083, China; Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, Changsha 410083, China
| | - Hao Tan
- School of Metallurgy and Environment, Central South University, Changsha 410083, China; Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, Changsha 410083, China
| | - Fan Feng
- School of Metallurgy and Environment, Central South University, Changsha 410083, China; Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, Changsha 410083, China
| | - Zhao-Meng Xu
- School of Metallurgy and Environment, Central South University, Changsha 410083, China; Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, Changsha 410083, China
| | - Qaisar Mahmood
- Department of Environmental Sciences, COMSATS University Islamabad, Abbottabad Campus, 22060, Pakistan
| | - Weizhi Zeng
- School of Metallurgy and Environment, Central South University, Changsha 410083, China; Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, Changsha 410083, China
| | - Xiao-Bo Min
- School of Metallurgy and Environment, Central South University, Changsha 410083, China; Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, Changsha 410083, China
| | - Chong-Jian Tang
- School of Metallurgy and Environment, Central South University, Changsha 410083, China; Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, Changsha 410083, China.
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