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Wang Z, Wang H, Nie Q, Ding Y, Lei Z, Zhang Z, Shimizu K, Yuan T. Pb(II) bioremediation using fresh algal-bacterial aerobic granular sludge and its underlying mechanisms highlighting the role of extracellular polymeric substances. JOURNAL OF HAZARDOUS MATERIALS 2023; 444:130452. [PMID: 36435038 DOI: 10.1016/j.jhazmat.2022.130452] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 11/03/2022] [Accepted: 11/19/2022] [Indexed: 06/16/2023]
Abstract
Lead (Pb) discharged from rural industries poses a significant threat to the environment and human health. Algal-bacterial aerobic granular sludge (A-B AGS) is a promising alternative for sewage treatment with high efficiency and good settleability. In this study, Pb(II) biosorption using fresh A-B AGS was investigated for the first time. The important role of extracellular polymeric substances (EPS) was revealed with the involved mechanisms being clarified. The desorbents for Pb recovery from Pb-loaded A-B AGS were also screened. Results showed that A-B AGS has an excellent maximum Pb adsorption capacity of 72.4 mg·g-1 at pH 6.0. EPS plays an important role in keeping microbial activity, Pb bonding, and providing metal ions (Ca, Na and Mg) for Pb ion exchanges. Electrostatic interaction, ion exchange, and bonding to functional groups may occur orderly in the Pb biosorption process and the formation of pyromorphite (Pb5(PO4)3Cl) contributes to Pb biosorption. About 66 % of the adsorbed Pb was accumulated in the A-B AGS microbial cells. Na2EDTA (0.05 M) can recover 60.3 % of the loaded Pb with the highest microbial activity of granules being remained. All the findings will provide the theoretical basis for the large-scale application of A-B AGS to bioremediate Pb(II)-containing wastewater.
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Affiliation(s)
- Zhiwei Wang
- Graduate School of Science and Technology, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan
| | - Hanxiao Wang
- Graduate School of Science and Technology, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan
| | - Qi Nie
- Graduate School of Science and Technology, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan
| | - Yi Ding
- Graduate School of Science and Technology, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan
| | - Zhongfang Lei
- Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan
| | - Zhenya Zhang
- Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan
| | - Kazuya Shimizu
- Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan
| | - Tian Yuan
- Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan.
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Wang C, Liu J, Xu X, Zhu L. Response of methanogenic granules enhanced by magnetite to ammonia stress. WATER RESEARCH 2022; 212:118123. [PMID: 35121418 DOI: 10.1016/j.watres.2022.118123] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 01/24/2022] [Accepted: 01/25/2022] [Indexed: 06/14/2023]
Abstract
Excessive ammonia has an inhibitory effect on anaerobic granular sludge (AnGS) when treating industrial wastewater with high concentration of ammonia and organic matters. The addition of conductive materials has been widely reported to improve the AnGS activity, which has the potential to alleviate the ammonia inhibition. In this study, the addition of magnetite was carried out to enhance the activity of AnGS in UASB reactor, then the response of AnGS to different ammonia levels was investigated. Results showed that magnetite facilitated the enrichment of Methanosaeta and Clostridium sensu stricto 1. Under the ammonia stress (up to 5 g TAN/L), it was interesting that Methanosaeta was better retained (abundance of 45.8%), and the abundance of ammonia-resistant Clostridium sensu stricto 1 increased to 34.3% in presence of magnetite. RT-qPCR analysis revealed that Methanosaeta could maintain metabolically active for counteracting the ammonia inhibition along with the higher transcription of genes encoding for CO2-dependent pathway. The electron transport activity and ATP content of AnGS were 1.25-2.12 and 1.23-2.56 folds higher than those in the control group, respectively. In addition, the AnGS could maintain the stability of structure because Methanosaeta was the skeleton of AnGS. As a result, the analysis of enzyme activity showed that the overall methanogenic metabolism was more active, thus ensured the effective operation of UASB reactor. This study provided the scientific understanding about the role of magnetite to alleviate the ammonia inhibition, and had important implications for stable treatment and recycling of industrial wastewater.
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Affiliation(s)
- Chen Wang
- Institute of Environment Pollution Control and Treatment, College of Environmental and Resource Science, Zhejiang University, Hangzhou 310058, China
| | - Jieyi Liu
- Institute of Environment Pollution Control and Treatment, College of Environmental and Resource Science, Zhejiang University, Hangzhou 310058, China
| | - Xiangyang Xu
- Institute of Environment Pollution Control and Treatment, College of Environmental and Resource Science, Zhejiang University, Hangzhou 310058, China; Zhejiang Province Key Laboratory for Water Pollution Control and Environmental Safety, Hangzhou 310058, China; Zhejiang Provincial Engineering Laboratory of Water Pollution Control, Hangzhou 310058, China
| | - Liang Zhu
- Institute of Environment Pollution Control and Treatment, College of Environmental and Resource Science, Zhejiang University, Hangzhou 310058, China; Zhejiang Province Key Laboratory for Water Pollution Control and Environmental Safety, Hangzhou 310058, China; Zhejiang Provincial Engineering Laboratory of Water Pollution Control, Hangzhou 310058, China.
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3
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Xu D, Fan J, Li W, Chen W, Pan C, Kang D, Li Y, Shan S, Zheng P. Deciphering correlation between permeability and size of anammox granule: "pores as medium". WATER RESEARCH 2021; 191:116832. [PMID: 33485080 DOI: 10.1016/j.watres.2021.116832] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 12/30/2020] [Accepted: 01/09/2021] [Indexed: 06/12/2023]
Abstract
Anammox granular sludge bed technology has been widely applied for its attractive advantages. Efficient mass transfer is an important factor for the anammox granules to play their role. In this study, steady-state anammox granules were used to investigate the correlation between the permeability and granule size with the granule pore as pivot. The results of size distribution showed that the anammox granules could be divided into 6 groups: 200-500 µm (I), 500-1000 µm (II), 1000-1500 µm (III), 1500-2000 µm (IV), 2000-3000 µm (V) and ≥3000 µm (VI). The results of settling experiment demonstrated that the permeability of anammox granules was negatively correlated with the granule size. The fluid collection efficiency declined from 39.4% to 9.3% for granule group I to III, and further to 0 for granule group IV to VI (granule size was larger than 1.5 mm). The observation of micro-CT revealed that the pore structure of anammox granules varied significantly with the increase of granule size, forming a denser surface layer and sparser interior. The chemical analysis and microscopic observation indicated that the pore plugging of surface layer by cell proliferation and EPS secretion was the main cause for the permeability deterioration. The findings of this study will help to understand the mass transfer of anammox granules and promote the development of anammox processes.
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Affiliation(s)
- Dongdong Xu
- Department of Environmental Engineering, College of Environmental & Resource Sciences, Zhejiang University, Hangzhou, China
| | - Jiahui Fan
- Department of Environmental Engineering, College of Environmental & Resource Sciences, Zhejiang University, Hangzhou, China
| | - Wenji Li
- Department of Environmental Engineering, College of Environmental & Resource Sciences, Zhejiang University, Hangzhou, China
| | - Wenda Chen
- Department of Environmental Engineering, College of Environmental & Resource Sciences, Zhejiang University, Hangzhou, China
| | - Chao Pan
- Department of Environmental Engineering, College of Environmental & Resource Sciences, Zhejiang University, Hangzhou, China
| | - Da Kang
- Department of Environmental Engineering, College of Environmental & Resource Sciences, Zhejiang University, Hangzhou, China
| | - Yiyu Li
- Department of Environmental Engineering, College of Environmental & Resource Sciences, Zhejiang University, Hangzhou, China
| | - Shengdao Shan
- School of Environmental and Natural Resources, Zhejiang University of Science & Technology, China
| | - Ping Zheng
- Department of Environmental Engineering, College of Environmental & Resource Sciences, Zhejiang University, Hangzhou, China.
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van den Berg L, Kirkland CM, Seymour JD, Codd SL, van Loosdrecht MCM, de Kreuk MK. Heterogeneous diffusion in aerobic granular sludge. Biotechnol Bioeng 2020; 117:3809-3819. [PMID: 32725888 PMCID: PMC7818175 DOI: 10.1002/bit.27522] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 07/10/2020] [Accepted: 07/23/2020] [Indexed: 01/21/2023]
Abstract
Aerobic granular sludge (AGS) technology allows simultaneous nitrogen, phosphorus, and carbon removal in compact wastewater treatment processes. To operate, design, and model AGS reactors, it is essential to properly understand the diffusive transport within the granules. In this study, diffusive mass transfer within full‐scale and lab‐scale AGS was characterized with nuclear magnetic resonance (NMR) methods. Self‐diffusion coefficients of water inside the granules were determined with pulsed‐field gradient NMR, while the granule structure was visualized with NMR imaging. A reaction‐diffusion granule‐scale model was set up to evaluate the impact of heterogeneous diffusion on granule performance. The self‐diffusion coefficient of water in AGS was ∼70% of the self‐diffusion coefficient of free water. There was no significant difference between self‐diffusion in AGS from full‐scale treatment plants and from lab‐scale reactors. The results of the model showed that diffusional heterogeneity did not lead to a major change of flux into the granule (<1%). This study shows that differences between granular sludges and heterogeneity within granules have little impact on the kinetic properties of AGS. Thus, a relatively simple approach is sufficient to describe mass transport by diffusion into the granules.
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Affiliation(s)
- Lenno van den Berg
- Department of Water Management, Delft University of Technology, Delft, The Netherlands
| | - Catherine M Kirkland
- Center for Biofilm Engineering, Montana State University, Bozeman, Montana.,Department of Civil Engineering, Montana State University, Bozeman, Montana
| | - Joseph D Seymour
- Center for Biofilm Engineering, Montana State University, Bozeman, Montana.,Department of Chemical and Biological Engineering, Montana State University, Bozeman, Montana
| | - Sarah L Codd
- Center for Biofilm Engineering, Montana State University, Bozeman, Montana.,Department of Mechanical and Industrial Engineering, Montana State University, Bozeman, Montana
| | | | - Merle K de Kreuk
- Department of Water Management, Delft University of Technology, Delft, The Netherlands
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5
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Kirkland CM, Krug JR, Vergeldt FJ, van den Berg L, Velders AH, Seymour JD, Codd SL, Van As H, de Kreuk MK. Characterizing the structure of aerobic granular sludge using ultra-high field magnetic resonance. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2020; 82:627-639. [PMID: 32970616 DOI: 10.2166/wst.2020.341] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Despite aerobic granular sludge wastewater treatment plants operating around the world, our understanding of internal granule structure and its relation to treatment efficiency remains limited. This can be attributed in part to the drawbacks of time-consuming, labor-intensive, and invasive microscopy protocols which effectively restrict samples sizes and may introduce artefacts. Time-domain nuclear magnetic resonance (NMR) allows non-invasive measurements which describe internal structural features of opaque, complex materials like biofilms. NMR was used to image aerobic granules collected from five full-scale wastewater treatment plants in the Netherlands and United States, as well as laboratory granules and control beads. T1 and T2 relaxation-weighted images reveal heterogeneous structures that include high- and low-density biofilm regions, water-like voids, and solid-like inclusions. Channels larger than approximately 50 μm and connected to the bulk fluid were not visible. Both cluster and ring-like structures were observed with each granule source having a characteristic structural type. These structures, and their NMR relaxation behavior, were stable over several months of storage. These observations reveal the complex structures within aerobic granules from a range of sources and highlight the need for non-invasive characterization methods like NMR to be applied in the ongoing effort to correlate structure and function.
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Affiliation(s)
- Catherine M Kirkland
- Department of Civil Engineering, Montana State University, 205 Cobleigh, Bozeman, Montana, 59717, USA E-mail: ; Center for Biofilm Engineering, Montana State University, 366 Barnard, Bozeman, Montana, 59717, USA
| | - Julia R Krug
- Laboratory of BioNanoTechnology, Wageningen University and Research, Axis building, Bornse Weilanden 9, 6708 WG, Wageningen, The Netherlands; Laboratory of Biophysics and MAGNEtic Resonance Research FacilitY (MAGNEFY), Wageningen University and Research, Helix building, Stippeneng 4, 6708 WG, Wageningen, The Netherlands
| | - Frank J Vergeldt
- Laboratory of Biophysics and MAGNEtic Resonance Research FacilitY (MAGNEFY), Wageningen University and Research, Helix building, Stippeneng 4, 6708 WG, Wageningen, The Netherlands
| | - Lenno van den Berg
- Department of Water Management, Delft University of Technology, Stevinweg 1, 2628 CN, Delft, The Netherlands
| | - Aldrik H Velders
- Laboratory of BioNanoTechnology, Wageningen University and Research, Axis building, Bornse Weilanden 9, 6708 WG, Wageningen, The Netherlands
| | - Joseph D Seymour
- Center for Biofilm Engineering, Montana State University, 366 Barnard, Bozeman, Montana, 59717, USA; Department of Chemical and Biological Engineering, Montana State University, 306 Cobleigh, Bozeman, Montana, 59717, USA
| | - Sarah L Codd
- Department of Mechanical and Industrial Engineering, Montana State University, 220 Roberts, Bozeman, Montana, 59717, USA
| | - Henk Van As
- Laboratory of Biophysics and MAGNEtic Resonance Research FacilitY (MAGNEFY), Wageningen University and Research, Helix building, Stippeneng 4, 6708 WG, Wageningen, The Netherlands
| | - Merle K de Kreuk
- Department of Water Management, Delft University of Technology, Stevinweg 1, 2628 CN, Delft, The Netherlands
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Lü F, Wang J, Shao L, He P. Enzyme disintegration with spatial resolution reveals different distributions of sludge extracellular polymer substances. BIOTECHNOLOGY FOR BIOFUELS 2016; 9:29. [PMID: 26843892 PMCID: PMC4739380 DOI: 10.1186/s13068-016-0444-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Accepted: 01/20/2016] [Indexed: 05/22/2023]
Abstract
BACKGROUND To understand the intrinsic role of hydrolytic enzymes in sludge treatment, particularly their effect on the digestibility and dewaterability of sludge, activated sludge flocs were disintegrated using various techniques that included different enzymes (amylase, cellulase, proteinase, DNase, and polygalacturonase), pH adjustment, and temperature adjustment. The effectiveness of each enzyme treatment was pinpointed by quantifying the spatial distribution of each type of organic matters (protein, polysaccharide, DNA, fluorescent organics) in outer layer extracellular polymeric substances (EPS), inner layer EPS, and cells. RESULTS Most hydrolytic enzymes functioned only owing to a temperature or pH effect. The release of organic matter from the interior fraction of EPS to the exterior fraction was prompted under high pH and temperature even without enzyme addition. The effectiveness of enzyme addition was only significant for cellulase and polygalacturonase treatments. Polygalacturonase unexpectedly increased the total EPS polysaccharides up to seven times, accompanied with improved dewaterability, while the amount of EPS proteins was almost unchanged. Combining chemical and morphological evidence, a new conceptual model considering the spatial distribution of polygalacturonic acid-like matter, proteins, cellulose, and other organics in EPS was proposed. CONCLUSIONS Polygalacturonic acid-like matter hydrolysis caused significant release of polysaccharides. Polygalacturonase released polysaccharides while keeping proteins unreleased. Temperature and pH adjustment were as effective as enzyme at sludge disintegration. Cellulose hydrolysis led to massive release of all kinds of organic matters. A new conceptual sludge structure model regarding organic components is proposed.
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Affiliation(s)
- Fan Lü
- />State Key Laboratory of Pollution Control and Resources Reuse, Tongji University, 1239 Siping Road, Shanghai, 200092 People’s Republic of China
| | - Jingwen Wang
- />State Key Laboratory of Pollution Control and Resources Reuse, Tongji University, 1239 Siping Road, Shanghai, 200092 People’s Republic of China
| | - Liming Shao
- />State Key Laboratory of Pollution Control and Resources Reuse, Tongji University, 1239 Siping Road, Shanghai, 200092 People’s Republic of China
- />Institute of Waste Treatment and Reclamation, Tongji University, Shanghai, 200092 People’s Republic of China
- />Centre for the Technology Research and Training on Household Waste in Small Towns and Rural Area, Ministry of Housing and Urban-Rural Development (MOHURD) of China, Shanghai, People’s Republic of China
| | - Pinjing He
- />State Key Laboratory of Pollution Control and Resources Reuse, Tongji University, 1239 Siping Road, Shanghai, 200092 People’s Republic of China
- />Institute of Waste Treatment and Reclamation, Tongji University, Shanghai, 200092 People’s Republic of China
- />Centre for the Technology Research and Training on Household Waste in Small Towns and Rural Area, Ministry of Housing and Urban-Rural Development (MOHURD) of China, Shanghai, People’s Republic of China
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7
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Liu L, Qian C, Jiang L, Yu HQ. Direct three-dimensional characterization and multiscale visualization of wheat straw deconstruction by white rot fungus. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:9819-9825. [PMID: 25072830 DOI: 10.1021/es5020983] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Microbial degradation of lignocellulose for resource and energy recovery has received increasing interest. Despite its obvious importance, the mechanism behind the biodegradation, especially the changes of morphological structure and surface characteristics, has not been fully understood. Here, we used three-dimensional (3D) characterization and multiscale visualization methods, in combination with chemical compositional analyses, to elucidate the degradation process of wheat straw by a white rot fungus, Phanerochaete chrysosporium. It was found that the fungal attack initiated from stomata. Lignin of the straw decayed in both size and quantity, and heterogeneity in the biodegradation was observed. After treatment with the fungus, the straw surface turned from hydrophobic to hydrophilic, and the adhesion of the straw surface increased in the fungal degradation. The morphology of the straw outer layer became heterogeneous and loose with the formation of many holes with various sizes. The wasp-tunnels-like structure of the collenchyma and parenchyma of the straw as well as the fungal hyphae interspersed inside the straw structure were clearly visualized in the 3D reconstruction structure. This work offers a new insight into the mechanism of lignocellulose biodegradation and demonstrates that multiscale visualization methods could be a useful tool to explore such complex processes.
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Affiliation(s)
- Li Liu
- School of Chemistry and Environment, BeiHang University , Beijing, 100191, China
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Wan C, Yang X, Lee DJ, Zhang Q, Li J, Liu X. Formation of filamentous aerobic granules: role of pH and mechanism. Appl Microbiol Biotechnol 2014; 98:8389-97. [DOI: 10.1007/s00253-014-5857-6] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Revised: 05/23/2014] [Accepted: 05/25/2014] [Indexed: 11/30/2022]
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9
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Zhou D, Niu S, Xiong Y, Yang Y, Dong S. Microbial selection pressure is not a prerequisite for granulation: dynamic granulation and microbial community study in a complete mixing bioreactor. BIORESOURCE TECHNOLOGY 2014; 161:102-108. [PMID: 24690580 DOI: 10.1016/j.biortech.2014.03.001] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2014] [Revised: 02/27/2014] [Accepted: 03/01/2014] [Indexed: 06/03/2023]
Abstract
Microbial selection pressure is traditionally supposed as a prerequisite for aerobic granulation. This work gives a different insight on this issue. Fluorescent microspheres were used to label the flocculent biomass granulation for a period of 47days in a continuous-flow bioreactor. Analysis of the distribution of fluorescent microspheres in granules revealed that the terminal phase of granulation is in a dynamic steady state, where bioflocs detach, collide and aggregate randomly. This revealed that the un-granulated biomass was the result of the dynamic aggregation and breakage, rather than the microbial species unable to be granulated. Furthermore, denaturing gradient gel electrophoresis (DGGE) profile and UPGMA dendrogram results showed similar microbial communities during the granulation. To sum up, microbial selection pressure was not a prerequisite for aerobic granulation from both of the dynamic granulation steps and molecular biology aspects.
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Affiliation(s)
- Dandan Zhou
- Key Lab of Groundwater Resources and Environment, Ministry of Education, Jilin University, Changchun 130021, China
| | - Shu Niu
- Key Lab of Groundwater Resources and Environment, Ministry of Education, Jilin University, Changchun 130021, China
| | - Yongjiao Xiong
- Key Lab of Groundwater Resources and Environment, Ministry of Education, Jilin University, Changchun 130021, China
| | - Yang Yang
- Key Lab of Groundwater Resources and Environment, Ministry of Education, Jilin University, Changchun 130021, China
| | - Shuangshi Dong
- Key Lab of Groundwater Resources and Environment, Ministry of Education, Jilin University, Changchun 130021, China.
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10
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Aerobic granules: microbial landscape and architecture, stages, and practical implications. Appl Environ Microbiol 2014; 80:3433-41. [PMID: 24657859 DOI: 10.1128/aem.00250-14] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
For the successful application of aerobic granules in wastewater treatment, granules containing an appropriate microbial assembly able to remove contaminants should be retained and propagated within the reactor. To manipulate and/or optimize this process, a good understanding of the formation and dynamic architecture of the granules is desirable. Models of granules often assume a spherical shape with an outer layer and an inner core, but limited information is available regarding the extent of deviations from such assumptions. We report on new imaging approaches to gain detailed insights into the structural characteristics of aerobic granules. Our approach stained all components of the granule to obtain a high quality contrast in the images; hence limitations due to thresholding in the image analysis were overcome. A three-dimensional reconstruction of the granular structure was obtained that revealed the mesoscopic impression of the cavernlike interior of the structure, showing channels and dead-end paths in detail. In "old" granules, large cavities allowed for the irrigation and growth of dense microbial colonies along the path of the channels. Hence, in some areas, paradoxically higher biomass content was observed in the inner part of the granule compared to the outer part. Microbial clusters "rooting" from the interior of the mature granule structure indicate that granules mainly grow via biomass outgrowth and not by aggregation of small particles. We identify and discuss phenomena contributing to the life cycle of aerobic granules. With our approach, volumetric tetrahedral grids are generated that may be used to validate complex models of granule formation.
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Costa JC, Mesquita DP, Amaral AL, Alves MM, Ferreira EC. Quantitative image analysis for the characterization of microbial aggregates in biological wastewater treatment: a review. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2013; 20:5887-5912. [PMID: 23716077 DOI: 10.1007/s11356-013-1824-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Accepted: 05/13/2013] [Indexed: 06/02/2023]
Abstract
Quantitative image analysis techniques have gained an undeniable role in several fields of research during the last decade. In the field of biological wastewater treatment (WWT) processes, several computer applications have been developed for monitoring microbial entities, either as individual cells or in different types of aggregates. New descriptors have been defined that are more reliable, objective, and useful than the subjective and time-consuming parameters classically used to monitor biological WWT processes. Examples of this application include the objective prediction of filamentous bulking, known to be one of the most problematic phenomena occurring in activated sludge technology. It also demonstrated its usefulness in classifying protozoa and metazoa populations. In high-rate anaerobic processes, based on granular sludge, aggregation times and fragmentation phenomena could be detected during critical events, e.g., toxic and organic overloads. Currently, the major efforts and needs are in the development of quantitative image analysis techniques focusing on its application coupled with stained samples, either by classical or fluorescent-based techniques. The use of quantitative morphological parameters in process control and online applications is also being investigated. This work reviews the major advances of quantitative image analysis applied to biological WWT processes.
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Affiliation(s)
- J C Costa
- Institute for Biotechnology and Bioengineering (IBB), Centre of Biological Engineering, Universidade do Minho, 4710-057, Braga, Portugal
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12
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Zhu L, Dai X, Lv M, Xu X. Correlation analysis of major control factors for the formation and stabilization of aerobic granule. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2013; 20:3165-3175. [PMID: 23054769 DOI: 10.1007/s11356-012-1202-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2012] [Accepted: 09/14/2012] [Indexed: 06/01/2023]
Abstract
In recent years, aerobic granular sludge technology has demonstrated significant advantages in areas such as the sludge-water separation, residual sludge minimization, simultaneous biological nitrogen and phosphorus removal, and toxic organic compounds degradation in biological wastewater treatment. However, the critical control factors and their relation during sludge granulation have not been revealed indeed, and the stability of aerobic granular sludge is still not good. The Gray's correlation analysis was used to investigate the relationship of aerobic granular characteristics and control factors in the study. Results showed that the organic loading rate, hydraulic shear stress, and sludge settling time were the major factors affecting the aerobic sludge granulation, and the associated regulating strategy was important for the stabilization of granular sludge system. Based on above results, the mechanism of aerobic sludge granulation was proposed, and it was expected to favor the application of aerobic granular sludge technology.
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Affiliation(s)
- Liang Zhu
- Department of Environmental Engineering, Zhejiang University, Hangzhou 310058, China
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Su KZ, Ni BJ, Yu HQ. Modeling and optimization of granulation process of activated sludge in sequencing batch reactors. Biotechnol Bioeng 2013; 110:1312-22. [DOI: 10.1002/bit.24812] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Revised: 12/12/2012] [Accepted: 12/14/2012] [Indexed: 11/08/2022]
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14
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15
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Liu L, Sheng GP, Li WW, Tong ZH, Zeng RJ, Liu JX, Xie J, Peng SC, Yu HQ. Cultivation of aerobic granular sludge with a mixed wastewater rich in toxic organics. Biochem Eng J 2011. [DOI: 10.1016/j.bej.2011.07.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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