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Zhang Y, Lin X, Xia T, Chen H, Huang F, Wei C, Qiu G. Effects of intensive chlorine disinfection on nitrogen and phosphorus removal in WWTPs. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 918:170273. [PMID: 38280590 DOI: 10.1016/j.scitotenv.2024.170273] [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: 10/07/2023] [Revised: 12/25/2023] [Accepted: 01/17/2024] [Indexed: 01/29/2024]
Abstract
The increased use of disinfection since the pandemic has led to increased effective chlorine concentration in municipal wastewater. Whereas, the specific impacts of active chlorine on nitrogen and phosphorus removal, the mediating communities, and the related metabolic activities in wastewater treatment plants (WWTPs) lack systematic investigation. We systematically analyzed the influences of chlorine disinfection on nitrogen and phosphorus removal activities using activated sludge from five full-scale WWTPs. Results showed that at an active chlorine concentration of 1.0 mg/g-SS, the nitrogen and phosphorus removal systems were not significantly affected. Major effects were observed at 5.0 mg/g-SS, where the nitrogen and phosphorus removal efficiency decreased by 38.9 % and 44.1 %, respectively. At an active chlorine concentration of 10.0 mg/g-SS, the nitrification, denitrification, phosphorus release and uptake activities decreased by 15.1 %, 69.5-95.9 %, 49.6 % and 100 %, respectively. The proportion of dead cells increased by 6.1 folds. Reverse transcriptional quantitative polymerase chain reaction (RT-qPCR) analysis showed remarkable inhibitions on transcriptions of the nitrite oxidoreductase gene (nxrB), the nitrite reductase genes (nirS and nirK), and the nitrite reductase genes (narG). The nitrogen and phosphorus removal activities completely disappeared with an active chlorine concentration of 25.0 mg/g-SS. Results also showed distinct sensitivities of different functional bacteria in the activated sludge. Even different species within the same functional group differ in their susceptibility. This study provides a reference for the understanding of the threshold active chlorine concentration values which may potentially affect biological nitrogen and phosphorus removal in full-scale WWTPs, which are expected to be beneficial for decision-making in WWTPs to counteract the potential impacts of increased active chlorine concentrations in the influent wastewater.
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Affiliation(s)
- Yixing Zhang
- School of Environment and Energy, South China University of Technology, Guangzhou 510006, China
| | - Xueran Lin
- Guangzhou Sewage Purification Co., Ltd, Guangzhou 510006, China
| | - Tang Xia
- Guangzhou Sewage Purification Co., Ltd, Guangzhou 510006, China
| | - Hang Chen
- School of Environment and Energy, South China University of Technology, Guangzhou 510006, China
| | - Fu Huang
- School of Environment and Energy, South China University of Technology, Guangzhou 510006, China
| | - Chaohai Wei
- School of Environment and Energy, South China University of Technology, Guangzhou 510006, China; Guangdong Provincial Key Laboratory of Solid Wastes Pollution Control and Recycling, Guangzhou 510006, China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, Guangzhou 510006, China
| | - Guanglei Qiu
- School of Environment and Energy, South China University of Technology, Guangzhou 510006, China; Guangdong Provincial Key Laboratory of Solid Wastes Pollution Control and Recycling, Guangzhou 510006, China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, Guangzhou 510006, China.
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Wang Y, Wang H, Chen H, Dai X. Metatranscriptome analysis unveils the mechanisms of zero-valent iron enhancing reactivation of starvation hydrolysis acidification sludge by inducing high-level gene expression. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 899:165696. [PMID: 37482355 DOI: 10.1016/j.scitotenv.2023.165696] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 07/18/2023] [Accepted: 07/19/2023] [Indexed: 07/25/2023]
Abstract
Hydrolysis acidification (HA) is a promising method for wastewater treatment and resource recovery. However, the extended time required for bacterial reactivation after starvation or a change in living conditions often poses a challenge to the efficient operation of the system. Although the addition of zero-valent iron (ZVI) could enhance HA performance, its effects on sludge reactivation in the HA process are not fully understood. In this study, ZVI was employed to accelerate sludge reactivation and its involved genetic mechanisms were unveiled. The results demonstrated that ZVI addition activated the sludge within 35 days with stable HA performance. Sludge characteristics revealed that ZVI improved active biomass, enzyme activity (by 11.4 % ∼ 26.7 %), ETS activity (by 566 %), and cell viability, with a higher concentration of MLVSS, live cells, more microbial byproducts in EPS, and relative abundance of HA bacteria (63.41 %). Moreover, metatranscriptome analysis showed that ZVI upregulated the expression of genes related to key enzymes in carbohydrate degradation metabolism, biosynthesis of electron transfer media such as heme and ubiquinone, and biosynthesis of vital cofactors like vitamin B12 and folate during microbial growth and metabolism. These findings suggest that ZVI enhanced electron transfer, bacterial growth, and metabolism, resulting in effective starch conversion and VFAs generation. Overall, these results deepen our understanding of the mechanism by which ZVI enhanced HA sludge reactivation, providing valuable information for addressing sludge starvation issues in HA systems.
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Affiliation(s)
- Yanqiong Wang
- National Engineering Research Center for Urban Pollution Control, State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Hongwu Wang
- National Engineering Research Center for Urban Pollution Control, State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Key Laboratory of Urban Water Supply, Water Saving and Water Environment Governance in the Yangtze River Delta of Ministry of Water Resources, Tongji University, Shanghai 200092, China.
| | - Hongbin Chen
- National Engineering Research Center for Urban Pollution Control, State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Xiaohu Dai
- National Engineering Research Center for Urban Pollution Control, State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
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Alabresm A, Decho AW, Lead J. A novel method to estimate cellular internalization of nanoparticles into gram-negative bacteria: Non-lytic removal of outer membrane and cell wall. NANOIMPACT 2021; 21:100283. [PMID: 35559775 DOI: 10.1016/j.impact.2020.100283] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 12/10/2020] [Accepted: 12/10/2020] [Indexed: 06/15/2023]
Abstract
Bacteria efficiently take up small organic molecules and ions. However, the internalization of particulate forms, specifically nanoparticles (NPs) has been understudied and is a newly-emerging area of interest. However, determination of true cellular internalization is challenging owing to the difficulty of separating the aqueous phase from bacteria-associated NPs and, more importantly, of differentiating between internalized and NPs sorbed on bacteria surfaces. In this work, we developed and validated an extraction method which can operationally estimate internalization of metal NPs into Gram-negative bacteria. The outer cell membrane and cell wall, collectively called the periplasm, was successfully removed from bacteria using ethylenediaminetetraacetic acid (EDTA) at an optimized exposure period and concentration, without lysis of bacteria. This was followed by standard digestion and metal measurements. Verification of each step of the methodology was conducted by assessing both cellular and metal behavior. Specifically, the combined approaches of live/dead staining of bacteria, optical density measurements, transmission electron microscopy (TEM) and metal analyses of the supernatant indicated that the method operationally separated externally-sorbed NPs from those internalized actually localized within the bacterial cytoplasm. However, this new method is ideally used alongside other methods in a multi-method approach, to provide improved data quality. Therefore, it should be used with CSLM, FACS, TEM and other available methods.
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Affiliation(s)
- Amjed Alabresm
- Center for Environmental Nanoscience and Risk (CENR), Department of Environmental Health Sciences, Arnold School of Public Health, University of South Carolina, Columbia, SC 29208, USA; Department of Environmental Health Sciences, Arnold School of Public Health, University of South Carolina, Columbia, SC 29208, USA; Department of Biological Development of Shatt Al-Arab & N. Arabian Gulf, Marine Science Centre, University of Basrah, Basrah, Iraq
| | - Alan W Decho
- Department of Environmental Health Sciences, Arnold School of Public Health, University of South Carolina, Columbia, SC 29208, USA
| | - Jamie Lead
- Center for Environmental Nanoscience and Risk (CENR), Department of Environmental Health Sciences, Arnold School of Public Health, University of South Carolina, Columbia, SC 29208, USA.
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Leal C, Val del Río A, Mesquita DP, Amaral AL, Castro PM, Ferreira EC. Sludge volume index and suspended solids estimation of mature aerobic granular sludge by quantitative image analysis and chemometric tools. Sep Purif Technol 2020. [DOI: 10.1016/j.seppur.2019.116049] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Hohl L, Panckow RP, Schulz JM, Jurtz N, Böhm L, Kraume M. Description of Disperse Multiphase Processes: Quo Vadis? CHEM-ING-TECH 2018. [DOI: 10.1002/cite.201800079] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Lena Hohl
- Technische Universität Berlin; Chair of Chemical and Process Engineering; Ackerstraße 76 13355 Berlin Germany
| | - Robert P. Panckow
- Technische Universität Berlin; Chair of Chemical and Process Engineering; Ackerstraße 76 13355 Berlin Germany
| | - Joschka M. Schulz
- Technische Universität Berlin; Chair of Chemical and Process Engineering; Ackerstraße 76 13355 Berlin Germany
| | - Nico Jurtz
- Technische Universität Berlin; Chair of Chemical and Process Engineering; Ackerstraße 76 13355 Berlin Germany
| | - Lutz Böhm
- Technische Universität Berlin; Chair of Chemical and Process Engineering; Ackerstraße 76 13355 Berlin Germany
| | - Matthias Kraume
- Technische Universität Berlin; Chair of Chemical and Process Engineering; Ackerstraße 76 13355 Berlin Germany
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Leal C, Amaral AL, Costa MDL. Microbial-based evaluation of foaming events in full-scale wastewater treatment plants by microscopy survey and quantitative image analysis. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:15638-15650. [PMID: 27130343 DOI: 10.1007/s11356-016-6750-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 04/22/2016] [Indexed: 06/05/2023]
Abstract
Activated sludge systems are prone to be affected by foaming occurrences causing the sludge to rise in the reactor and affecting the wastewater treatment plant (WWTP) performance. Nonetheless, there is currently a knowledge gap hindering the development of foaming events prediction tools that may be fulfilled by the quantitative monitoring of AS systems biota and sludge characteristics. As such, the present study focuses on the assessment of foaming events in full-scale WWTPs, by quantitative protozoa, metazoa, filamentous bacteria, and sludge characteristics analysis, further used to enlighten the inner relationships between these parameters. In the current study, a conventional activated sludge system (CAS) and an oxidation ditch (OD) were surveyed throughout a period of 2 and 3 months, respectively, regarding their biota and sludge characteristics. The biota community was monitored by microscopic observation, and a new filamentous bacteria index was developed to quantify their occurrence. Sludge characteristics (aggregated and filamentous biomass contents and aggregate size) were determined by quantitative image analysis (QIA). The obtained data was then processed by principal components analysis (PCA), cross-correlation analysis, and decision trees to assess the foaming occurrences, and enlighten the inner relationships. It was found that such events were best assessed by the combined use of the relative abundance of testate amoeba and nocardioform filamentous index, presenting a 92.9 % success rate for overall foaming events, and 87.5 and 100 %, respectively, for persistent and mild events.
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Affiliation(s)
- Cristiano Leal
- Instituto Politécnico de Coimbra, ISEC, Rua Pedro Nunes, Quinta da Nora, 3030-199, Coimbra, Portugal
| | - António Luís Amaral
- Instituto Politécnico de Coimbra, ISEC, Rua Pedro Nunes, Quinta da Nora, 3030-199, Coimbra, Portugal.
- CEB-Centre of Biological Engineering, Universidade do Minho, Campus de Gualtar, 4710-057, Braga, Portugal.
| | - Maria de Lourdes Costa
- CERNAS-Center of Studies on Natural Resources, Environment and Society, Instituto Politécnico de Coimbra, ESAC, Bencanta, 3045-601, Coimbra, Portugal
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Dias PA, Dunkel T, Fajado DAS, Gallegos EDL, Denecke M, Wiedemann P, Schneider FK, Suhr H. Image processing for identification and quantification of filamentous bacteria in in situ acquired images. Biomed Eng Online 2016; 15:64. [PMID: 27287755 PMCID: PMC4902998 DOI: 10.1186/s12938-016-0197-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Accepted: 05/24/2016] [Indexed: 01/01/2023] Open
Abstract
Background In the activated sludge process, problems of filamentous bulking and foaming can occur due to overgrowth of certain filamentous bacteria. Nowadays, these microorganisms are typically monitored by means of light microscopy, commonly combined with staining techniques. As drawbacks, these methods are susceptible to human errors, subjectivity and limited by the use of discontinuous microscopy. The in situ microscope appears as a suitable tool for continuous monitoring of filamentous bacteria, providing real-time examination, automated analysis and eliminating sampling, preparation and transport of samples. In this context, a proper image processing algorithm is proposed for automated recognition and measurement of filamentous objects. Methods This work introduces a method for real-time evaluation of images without any staining, phase-contrast or dilution techniques, differently from studies present in the literature. Moreover, we introduce an algorithm which estimates the total extended filament length based on geodesic distance calculation. For a period of twelve months, samples from an industrial activated sludge plant were weekly collected and imaged without any prior conditioning, replicating real environment conditions. Results Trends of filament growth rate—the most important parameter for decision making—are correctly identified. For reference images whose filaments were marked by specialists, the algorithm correctly recognized 72 % of the filaments pixels, with a false positive rate of at most 14 %. An average execution time of 0.7 s per image was achieved. Conclusions Experiments have shown that the designed algorithm provided a suitable quantification of filaments when compared with human perception and standard methods. The algorithm’s average execution time proved its suitability for being optimally mapped into a computational architecture to provide real-time monitoring.
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Affiliation(s)
- Philipe A Dias
- Graduate Program in Electrical and Computer Engineering, Federal University of Technology Paraná, Av. Sete de Setembro 3165, Curitiba, 80230-901, Brazil. .,Department of Information Technology, Mannheim University of Applied Sciences, Paul-Wittsack-Str. 10, 68163, Mannheim, Germany.
| | - Thiemo Dunkel
- Institute for Urban Water and Waste Management, University of Duisburg-Essen, Universitätsstr. 15, 45141, Essen, Germany
| | - Diego A S Fajado
- Department of Information Technology, Mannheim University of Applied Sciences, Paul-Wittsack-Str. 10, 68163, Mannheim, Germany
| | - Erika de León Gallegos
- Institute for Urban Water and Waste Management, University of Duisburg-Essen, Universitätsstr. 15, 45141, Essen, Germany
| | - Martin Denecke
- Institute for Urban Water and Waste Management, University of Duisburg-Essen, Universitätsstr. 15, 45141, Essen, Germany
| | - Philipp Wiedemann
- Department of Biotechnology, Mannheim University of Applied Sciences, Paul-Wittsack-Str. 10, 68163, Mannheim, Germany
| | - Fabio K Schneider
- Graduate Program in Electrical and Computer Engineering, Federal University of Technology Paraná, Av. Sete de Setembro 3165, Curitiba, 80230-901, Brazil
| | - Hajo Suhr
- Department of Information Technology, Mannheim University of Applied Sciences, Paul-Wittsack-Str. 10, 68163, Mannheim, Germany
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8
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Mesquita DP, Amaral AL, Ferreira EC. Activated sludge characterization through microscopy: A review on quantitative image analysis and chemometric techniques. Anal Chim Acta 2013; 802:14-28. [DOI: 10.1016/j.aca.2013.09.016] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Revised: 09/05/2013] [Accepted: 09/07/2013] [Indexed: 02/07/2023]
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9
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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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Stalder T, Alrhmoun M, Louvet JN, Casellas M, Maftah C, Carrion C, Pons MN, Pahl O, Ploy MC, Dagot C. Dynamic assessment of the floc morphology, bacterial diversity, and integron content of an activated sludge reactor processing hospital effluent. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:7909-7917. [PMID: 23789899 DOI: 10.1021/es4008646] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The treatment of hospital effluents (HE) is a major concern, as they are suspected of disseminating drugs and antibiotic resistance determinants in the environment. In order to assess HE influence on wastewater treatment plant biomass, lab-scale conventional activated sludge systems (CAS) were continuously fed with real HE or urban effluent as a control. To gain insights into the main hurdles linked to HE treatment, we conducted a multiparameter study using classical physicochemical characterization, phase contrast and confocal laser scaning microscopy, and molecular biology (i.e., pyrosequencing) tools. HE caused erosion of floc structure and the production of extracellular polymeric substances attributed to the development of floc-forming bacteria. Adaptation of the sludge bacterial community to the HE characteristics, thus maintaining the purification performance of the biomass, was observed. Finally, the comparative metagenomic analysis of the CAS showed that HE treatment resulted in an increase of class 1 resistance integrons (RIs) and the introduction of Pseudomonas spp. into the bacterial community. HE treatment did not reduce the CAS process performance; nevertheless it increases the risk of dissemination into the environment of bacterial species and genetic determinants (RIs) involved in antibiotic resistance acquisition.
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Nuchtavorn N, Bek F, Macka M, Suntornsuk W, Suntornsuk L. Rapid separations of nile blue stained microorganisms as cationic charged species by chip-CE with LIF. Electrophoresis 2012; 33:1421-6. [DOI: 10.1002/elps.201100698] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Nantana Nuchtavorn
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy; Mahidol University; Bangkok; Thailand
| | - Fritz Bek
- Agilent Technologies; Waldbronn; Germany
| | - Mirek Macka
- Australian Centre for Research on Separation Science, School of Chemistry; University of Tasmania; Tasmania; Australia
| | - Worapot Suntornsuk
- Department of Microbiology, Faculty of Science; King Mongkut's University of Technology Thonburi; Bangkok; Thailand
| | - Leena Suntornsuk
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy; Mahidol University; Bangkok; Thailand
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Louvet JN, Attik G, Dumas D, Potier O, Pons MN. Simultaneous Gram and viability staining on activated sludge exposed to erythromycin: 3D CLSM time-lapse imaging of bacterial disintegration. Int J Hyg Environ Health 2011; 214:470-7. [DOI: 10.1016/j.ijheh.2011.02.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2010] [Revised: 02/01/2011] [Accepted: 02/14/2011] [Indexed: 10/18/2022]
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Piterina AV, Bartlett J, Pembroke JT. Morphological characterisation of ATAD thermophilic sludge; sludge ecology and settleability. WATER RESEARCH 2011; 45:3427-3438. [PMID: 21514948 DOI: 10.1016/j.watres.2011.03.054] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2010] [Revised: 03/30/2011] [Accepted: 03/30/2011] [Indexed: 05/30/2023]
Abstract
Autothermal thermophilic aerobic digestion (ATAD) is a biological wastewater treatment process used for stabilisation of domestic, animal, food and pharmaceutical sludges, and wastewater. It produces a high-quality effluent due to thermophilic processing conditions, however the stabilised sludge has poor settling characteristics, a high water content, low compaction capacity and is difficult to dewater by mechanical processes alone. These factors impact transport and disposal of processed ATAD sludge. We have carried out a detailed morphological characterisation of ATAD sludge at all stages of the ATAD process in an attempt to determine key characteristics of the sludge that might be responsible for its poor dewatering and settleability. A number of microscopic techniques including electron, optical, wide field and laser scanning confocal microscopy were applied to fresh, fixed or embedded sludge taken at various stages during a full scale ATAD process treating domestic sludge. The spatial distributions of structural sludge matrix components were determined and suggested a highly dynamic sludge morphology during the overall process. Large amounts of fibres were observed in the feed sludge, whereas thermophilic sludge liquor with low settleability was shown to have a lower protein to polysaccharide ratio (1:0.9) compared to the easily settled fraction where ratio values were in the range of (1:1.14-1:1.7) with a prevalence of protein constituents. ATAD sludge was also shown to contain colloids, slime, cellulose micro-particles and multiple hydrophobic droplets in the bulk liquor, factors that may markedly impact on sludge dewaterability characteristics. Laser scanning confocal microscopy demonstrated a superior ability to identify composition and spatial localisation of structural constituents in such a dispersed, high water content sludge.
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Affiliation(s)
- Anna V Piterina
- Molecular Biochemistry Laboratory, Department of Chemical and Environmental Sciences, University of Limerick, Limerick, Ireland.
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Louvet JN, Heluin Y, Attik G, Dumas D, Potier O, Pons MN. Assessment of erythromycin toxicity on activated sludge via batch experiments and microscopic techniques (epifluorescence and CLSM). Process Biochem 2010. [DOI: 10.1016/j.procbio.2010.03.036] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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15
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Louvet JN, Giammarino C, Potier O, Pons MN. Adverse effects of erythromycin on the structure and chemistry of activated sludge. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2010; 158:688-693. [PMID: 19896757 DOI: 10.1016/j.envpol.2009.10.021] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2009] [Revised: 10/07/2009] [Accepted: 10/15/2009] [Indexed: 05/28/2023]
Abstract
This study examines the effects of erythromycin on activated sludge from two French urban wastewater treatment plants (WWTPs). Wastewater spiked with 10 mg/L erythromycin inhibited the specific evolution rate of chemical oxygen demand (COD) by 79% (standard deviation 34%) and the specific N-NH4+ evolution rate by 41% (standard deviation 25%). A temporary increase in COD and tryptophan-like fluorescence, as well as a decrease in suspended solids, were observed in reactors with wastewater containing erythromycin. The destruction of activated sludge flocs was monitored by automated image analysis. The effect of erythromycin on nitrification was variable depending on the sludge origin. Erythromycin inhibited the specific nitrification rate in sludge from one WWTP, but increased the nitrification rate at the other facility.
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Affiliation(s)
- J N Louvet
- Laboratoire des Sciences du Génie Chimique-CNRS, Nancy University, INPL, 1, rue Grandville, BP 20451, F-54001 Nancy Cedex, France
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16
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Application of epifluorescence light microscopy (EFLM) to study the microstructure of wheat dough: a comparison with confocal scanning laser microscopy (CSLM) technique. J Cereal Sci 2010. [DOI: 10.1016/j.jcs.2009.09.002] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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17
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Malic S, Hill KE, Hayes A, Percival SL, Thomas DW, Williams DW. Detection and identification of specific bacteria in wound biofilms using peptide nucleic acid fluorescent in situ hybridization (PNA FISH). MICROBIOLOGY-SGM 2009; 155:2603-2611. [PMID: 19477903 DOI: 10.1099/mic.0.028712-0] [Citation(s) in RCA: 144] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Biofilms provide a reservoir of potentially infectious micro-organisms that are resistant to antimicrobial agents, and their importance in the failure of medical devices and chronic inflammatory conditions is increasingly being recognized. Particular research interest exists in the association of biofilms with wound infection and non-healing, i.e. chronic wounds. In this study, fluorescent in situ hybridization (FISH) was used in combination with confocal laser scanning microscopy (CLSM) to detect and characterize the spatial distribution of biofilm-forming bacteria which predominate within human chronic skin wounds (Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus sp. and Micrococcus sp.). In vitro biofilms were prepared using a constant-depth film fermenter and a reconstituted human epidermis model. In vivo biofilms were also studied using biopsy samples from non-infected chronic venous leg ulcers. The specificity of peptide nucleic acid (PNA) probes for the target organisms was confirmed using mixed preparations of planktonic bacteria and multiplex PNA probing. Identification and location of individual bacterial species within multi-species biofilms demonstrated that P. aeruginosa was predominant. CLSM revealed clustering of individual species within mixed-species biofilms. FISH analysis of archive chronic wound biopsy sections showed bacterial presence and allowed bacterial load to be determined. The application of this standardized procedure makes available an assay for identification of single- or multi-species bacterial populations in tissue biopsies. The technique provides a reliable tool to study bacterial biofilm formation and offers an approach to assess targeted biofilm disruption strategies in vivo.
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Affiliation(s)
- Sladjana Malic
- Tissue Engineering and Reparative Dentistry, School of Dentistry, Cardiff University, Heath Park, Cardiff CF14 4XY, UK
| | - Katja E Hill
- Tissue Engineering and Reparative Dentistry, School of Dentistry, Cardiff University, Heath Park, Cardiff CF14 4XY, UK
| | - Anthony Hayes
- School of Biosciences, Cardiff University, Park Place, Cardiff CF10 3US, UK
| | - Steven L Percival
- School of Medicine, University of West Virginia, Morgantown, WV 26506, USA
| | - David W Thomas
- Tissue Engineering and Reparative Dentistry, School of Dentistry, Cardiff University, Heath Park, Cardiff CF14 4XY, UK
| | - David W Williams
- Tissue Engineering and Reparative Dentistry, School of Dentistry, Cardiff University, Heath Park, Cardiff CF14 4XY, UK
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Carneiro S, Amaral AL, Veloso ACA, Dias T, Peres AM, Ferreira EC, Rocha I. Assessment of physiological conditions inE. colifermentations by epifluorescent microscopy and image analysis. Biotechnol Prog 2009; 25:882-91. [DOI: 10.1002/btpr.134] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Daims H, Wagner M. Quantification of uncultured microorganisms by fluorescence microscopy and digital image analysis. Appl Microbiol Biotechnol 2007; 75:237-48. [PMID: 17333172 DOI: 10.1007/s00253-007-0886-z] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2006] [Revised: 12/22/2006] [Accepted: 02/09/2007] [Indexed: 11/28/2022]
Abstract
Traditional cultivation-based methods to quantify microbial abundance are not suitable for analyses of microbial communities in environmental or medical samples, which consist mainly of uncultured microorganisms. Recently, different cultivation-independent quantification approaches have been developed to overcome this problem. Some of these techniques use specific fluorescence markers, for example ribosomal ribonucleic acid targeted oligonucleotide probes, to label the respective target organisms. Subsequently, the detected cells are visualized by fluorescence microscopy and are quantified by direct visual cell counting or by digital image analysis. This article provides an overview of these methods and some of their applications with emphasis on (semi-)automated image analysis solutions.
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Affiliation(s)
- Holger Daims
- Department für Mikrobielle Okologie, Universität Wien, Althanstrasse 14, 1090, Vienna, Austria.
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Maximova N, Dahl O. Environmental implications of aggregation phenomena: Current understanding. Curr Opin Colloid Interface Sci 2006. [DOI: 10.1016/j.cocis.2006.06.001] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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21
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Affiliation(s)
- Marian Navratil
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, USA
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Lopez C, Pons MN, Morgenroth E. Endogenous processes during long-term starvation in activated sludge performing enhanced biological phosphorus removal. WATER RESEARCH 2006; 40:1519-30. [PMID: 16631226 DOI: 10.1016/j.watres.2006.01.040] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2005] [Revised: 12/21/2005] [Accepted: 01/14/2006] [Indexed: 05/08/2023]
Abstract
In many biological wastewater treatment systems, bacterial growth and the amount of active biomass are limited by the availability of substrate. Under these low growth conditions, endogenous processes have a significant influence on the amount of active biomass and therefore, the overall system performance. In enhanced biological phosphorus removal (EBPR) systems endogenous processes can also influence the levels of the internal storage compounds of the polyphosphate accumulating organisms (PAO), directly affecting phosphorus removal performance. The purpose of this study was to evaluate the significance of different endogenous processes that occur during the long-term starvation of EBPR sludge under aerobic and anaerobic conditions. Activated sludge obtained from a laboratory sequencing batch reactor was used to perform a series of batch starvation experiments. Under aerobic starvation conditions we observed a significant decay of PAO (first-order decay rate of 0.15/d) together with a rapid utilization of polyhydroxyalkanoates (PHA) and a slower utilization of glycogen and polyphosphate to generate maintenance energy. On the other hand, anaerobic starvation was best described by maintenance processes that rapidly reduce the levels of polyphosphate and glycogen under starvation conditions while no significant decay of PAO was observed. The endogenous utilization of glycogen for maintenance purposes is currently not included in available EBPR models. Our experimental results suggest that mathematical models for in EBPR should differentiate between aerobic and anaerobic endogenous processes, as they influence active biomass and storage products differently.
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Affiliation(s)
- C Lopez
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, 3219 Newmark Civil Engineering Laboratory, 205 North Mathews Avenue, Urbana, IL 61801, USA
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Fall R, Kearns DB, Nguyen T. A defined medium to investigate sliding motility in a Bacillus subtilis flagella-less mutant. BMC Microbiol 2006; 6:31. [PMID: 16545127 PMCID: PMC1501027 DOI: 10.1186/1471-2180-6-31] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2005] [Accepted: 03/17/2006] [Indexed: 11/10/2022] Open
Abstract
Background We have recently shown that undomesticated strains of Bacillus subtilis can extensively colonize the surfaces of rich, semi-solid media, by a flagellum-independent mechanism and suggested that sliding motility is responsible for surface migration. Here we have used a flagella-less hag null mutant to examine and confirm sliding motility. Results Using a defined semi-solid medium we determined that a B. subtilis hag mutant colonized the surface in two stages, first as tendril-like clusters of cells followed by a profuse pellicle-like film. We determined the levels of macro- and micro-nutrients required for the tendril-to-film transition. Sufficient levels of each of the macronutrients, glycerol, Na-glutamate, and Na-phosphate, and inorganic nutrients, K+, Mg2+, Fe2+ and Mn2+, were required for robust film formation. The K+ requirement was quantified in more detail, and the thresholds for complete tendril coverage (50 μM KCl) or film coverage (2–3 mM KCl) were determined. In addition, disruption of the genes for the higher affinity K+ transporter (KtrAB), but not the lower affinity K+ transporter (KtrCD), strongly inhibited the formation of both tendrils and films, and could be partially overcome by high levels of KCl. Examination of hag tendrils by confocal scanning laser microscopy revealed that tendrils are multicellular structures, but that the cells are not as highly organized as cells in wild-type B. subtilis pellicles. Conclusion These results suggest that B. subtilis can use sliding motility to colonize surfaces, using a tendril-like growth mode when various macronutrients or micronutrients are limiting. If nutrients are balanced and sufficient, the surfaces between tendrils can be colonized by robust surface films. Sliding motility may represent a strategy for nutrient-deprived cells to colonize surfaces in natural environments, such as plant roots, and the media described here may be useful in investigations of this growth phenotype.
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Affiliation(s)
- Ray Fall
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309-0215, USA
| | - Daniel B Kearns
- Department of Molecular and Cellular Biology, Harvard University, 16 Divinity Ave., Cambridge, MA 02138, USA
- Department of Biology, Indiana University, Bloomington, IN 47405-7000, USA
| | - Tam Nguyen
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309-0215, USA
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Laser literature watch. Photomed Laser Surg 2005; 23:513-24. [PMID: 16262584 DOI: 10.1089/pho.2005.23.513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Liwarska-Bizukojc E. Application of Image Analysis Techniques in Activated Sludge Wastewater Treatment Processes. Biotechnol Lett 2005; 27:1427-33. [PMID: 16231212 DOI: 10.1007/s10529-005-1303-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2005] [Accepted: 07/19/2005] [Indexed: 10/25/2022]
Abstract
Image analytical techniques have been extensively developed to evaluate complex microbial aggregates such as sludge flocs and biofilms. This review covers the latest contributions concerning the application of image analysis to the activated sludge systems with respect to the most frequently used morphological parameters and relations between them and traditional wastewater treatment parameters. Recent developments have indicated that image analysis can be successfully used for the quantification of flocs and filamentous bacteria in the operating wastewater treatment plants, which enables prediction of bulking events and pinpoint flocs formation.
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Affiliation(s)
- Ewa Liwarska-Bizukojc
- Department of Environmental Engineering, Technical University of Lodz, Al. Politechniki 6, 90-924, Lodz, Poland.
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Mota C, Ridenoure J, Cheng J, de Los Reyes FL. High levels of nitrifying bacteria in intermittently aerated reactors treating high ammonia wastewater. FEMS Microbiol Ecol 2005; 54:391-400. [PMID: 16332337 DOI: 10.1016/j.femsec.2005.05.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2004] [Revised: 01/27/2005] [Accepted: 05/04/2005] [Indexed: 11/26/2022] Open
Abstract
Changes in the fractions of ammonia-oxidizing bacteria and nitrite-oxidizing bacteria in two laboratory-scale reactors were investigated using 16S rRNA probe hybridizations. The reactors were operated in intermittent aeration mode and different aeration cycles to treat anaerobically digested swine wastewater with ammonia concentrations up to 175 mg NH(3)-N/L. High ammonia removals (>98.8%) were achieved even with increased nitrogen loads and lower aeration: non-aeration time ratios of 1h:3h. Nitrosomonas/Nitrosococcus mobilis were the dominant ammonia-oxidizing bacteria in the reactors. Nitrospira-like organisms were the dominant nitrite-oxidizing bacteria during most of the investigation, but were occasionally outcompeted by Nitrobacter. High levels of nitrifiers were measured in the biomass of both reactors, and ammonia-oxidizing bacteria and nitrite-oxidizing bacterial levels adjusted to changing aeration: non-aeration time ratios. Theoretical ammonia-oxidizer fractions, determined by a mathematical model, were comparable to the measured values, although the measured biomass fractions were different at each stage while the theoretical values remained approximately constant. Stable ammonia removals and no nitrite accumulation were observed even when rRNA levels of ammonia oxidizers and nitrite-oxidizers reached a minimum of 7.2% and 8.6% of total rRNA, respectively. Stable nitrogen removal performance at an aeration: non-aeration ratio of 1h:3h suggests the possibility of significant savings in operational costs.
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Affiliation(s)
- Cesar Mota
- Department of Civil, Construction, and Environmental Engineering, North Carolina State University, 208 Mann Hall, Campus Box 7908, Raleigh, NC 27695-7908, USA
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