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Asgari G, Seid-Mohammadi A, Shokoohi R, Samarghandi MR, Daigger GT, Malekolkalami B, Khoshniyat R. Exposure of the static magnetic fields on the microbial growth rate and the sludge properties in the complete-mix activated sludge process (a Lab-scale study). Microb Cell Fact 2023; 22:195. [PMID: 37759209 PMCID: PMC10523802 DOI: 10.1186/s12934-023-02207-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 09/19/2023] [Indexed: 09/29/2023] Open
Abstract
BACKGROUND In this study, the effect of static magnetic fields (SMFs) on improving the performance of activated sludge process to enhance the higher rate of microbial growth biomass and improve sludge settling characteristics in real operation conditions of wastewater treatment plants has been investigated. The effect of SMFs (15 mT), hydraulic retention time, SRT, aeration time on mixed liquor suspended solids (MLSS) concentrations, mixed liquor volatile suspended solids (MLVSS) concentrations, α-factor, and pH in the complete-mix activated sludge (CMAS) process during 30 days of the operation, were evaluated. RESULTS There were not any differences between the concentration of MLSS in the case (2148.8 ± 235.6 mg/L) and control (2260.1 ± 296.0 mg/L) samples, however, the mean concentration of MLVSS in the case (1463.4 ± 419.2 mg/L) was more than the control samples (1244.1 ± 295.5 mg/L). Changes of the concentration of MLVSS over time, follow the first and second-order reaction with and without exposure of SMFs respectively. Moreover, the slope of the line and, the mean of α-factor in the case samples were 6.255 and, - 0.001 higher than the control samples, respectively. Changes in pH in both groups of the reactors were not observed. The size of the sluge flocs (1.28 µm) and, the spectra of amid I' (1440 cm-1) and II' (1650 cm-1) areas related to hydrogenase bond in the case samples were higher than the control samples. CONCLUSIONS SMFs have a potential to being considered as an alternative method to stimulate the microbial growth rate in the aeration reactors and produce bioflocs with the higher density in the second clarifiers.
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Affiliation(s)
- Ghorban Asgari
- Social Determinants of Health Research Center (SDHRC), Faculty of Public Health, Department of Environmental Health Engineering, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Abdolmotaleb Seid-Mohammadi
- Department of Environmental Health Engineering, School of Public Health, Research Centre for Health Sciences, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Reza Shokoohi
- Department of Environmental Health Engineering, School of Public Health, Research Centre for Health Sciences, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Mohammad Reza Samarghandi
- Department of Environmental Health Engineering, School of Public Health, Research Centre for Health Sciences, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Glen T Daigger
- Department of Civil and Environmental Engineering, University of Michigan, 177 EWRE Building, 1351 Beal Street, Ann Arbor, MI, 48109, USA
| | - Behrooz Malekolkalami
- Department of Physics, University of Kurdistan, P.O. Box 66177-15175, Sanandaj, Iran
| | - Ramin Khoshniyat
- Social Determinants of Health Research Center (SDHRC), Faculty of Public Health, Department of Environmental Health Engineering, Hamadan University of Medical Sciences, Hamadan, Iran.
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Ang RBQ, Nisar H, Khan MB, Tsai CY. Image segmentation of activated sludge phase contrast images using phase stretch transform. Microscopy (Oxf) 2019; 68:144-158. [PMID: 30496508 DOI: 10.1093/jmicro/dfy134] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 10/29/2018] [Accepted: 11/01/2018] [Indexed: 11/12/2022] Open
Abstract
Activated sludge (AS) is a biological treatment process that is employed in wastewater treatment plants. Filamentous bacteria in AS plays an important role in the settling ability of the sludge. Proper settling of the sludge is essential for normal functionality of the wastewater plants, where filamentous bulking is always a persistent problem preventing sludge from settling. The performance of AS plants is conventionally monitored by physico-chemical procedures. An alternative way of monitoring the AS in wastewater treatment process is to use image processing and analysis. Good performance of the image segmentation algorithms is important to quantify flocs and filaments in AS. In this article, an algorithm is proposed to perform segmentation of filaments in the phase contrast images using phase stretch transform. Different values of strength (S) and warp (W) are tested to obtain optimum segmentation results and decrease the halo and shade-off artefacts encountered in phase contrast microscopy. The performance of the algorithm is assessed using DICE coefficient, accuracy, false positive rate (FPR), false negative rate (FNR) and Rand index (RI). Sixty-one gold approximations of ground truth images were manually prepared to assess the segmentation results. Thirty-two of them were acquired at 10× magnification and 29 of them were acquired at 20× magnification. The proposed algorithm exhibits better segmentation performance with an average DICE coefficient equal to 52.25%, accuracy 99.74%, FNR 41.8% and FPR 0.14% and RI 99.49%, based on 61 images.
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Affiliation(s)
- Raymond Bing Quan Ang
- Department of Electronic Engineering, Faculty of Engineering and Green Technology, Universiti Tunku Abdul Rahman, Jalan Universiti, Bandar Barat, Kampar, Perak, Malaysia
| | - Humaira Nisar
- Department of Electronic Engineering, Faculty of Engineering and Green Technology, Universiti Tunku Abdul Rahman, Jalan Universiti, Bandar Barat, Kampar, Perak, Malaysia
| | - Muhammad Burhan Khan
- Department of Electrical Engineering, National University of Computer and Emerging Sciences, Shah Latif Town 75030, National Highway (N-5), Karachi, Pakistan
| | - Chi-Yi Tsai
- Department of Electrical and Computer Engineering, Tamkang University, No. 151, Yingzhuan Road, Tamsui District, New Taipei City, Taiwan R.O.C
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Khan MB, Nisar H, Ng CA, Lo PK, Yap VV. Generalized classification modeling of activated sludge process based on microscopic image analysis. ENVIRONMENTAL TECHNOLOGY 2018; 39:24-34. [PMID: 28278778 DOI: 10.1080/09593330.2017.1293166] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Accepted: 02/05/2017] [Indexed: 06/06/2023]
Abstract
The state of activated sludge wastewater treatment process (AS WWTP) is conventionally identified by physico-chemical measurements which are costly, time-consuming and have associated environmental hazards. Image processing and analysis-based linear regression modeling has been used to monitor the AS WWTP. But it is plant- and state-specific in the sense that it cannot be generalized to multiple plants and states. Generalized classification modeling for state identification is the main objective of this work. By generalized classification, we mean that the identification model does not require any prior information about the state of the plant, and the resultant identification is valid for any plant in any state. In this paper, the generalized classification model for the AS process is proposed based on features extracted using morphological parameters of flocs. The images of the AS samples, collected from aeration tanks of nine plants, are acquired through bright-field microscopy. Feature-selection is performed in context of classification using sequential feature selection and least absolute shrinkage and selection operator. A support vector machine (SVM)-based state identification strategy was proposed with a new agreement solver module for imbalanced data of the states of AS plants. The classification results were compared with state-of-the-art multiclass SVMs (one-vs.-one and one-vs.-all), and ensemble classifiers using the performance metrics: accuracy, recall, specificity, precision, F measure and kappa coefficient (κ). The proposed strategy exhibits better results by identification of different states of different plants with accuracy 0.9423, and κ 0.6681 for the minority class data of bulking.
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Affiliation(s)
- Muhammad Burhan Khan
- a Faculty of Engineering and Green Technology , Universiti Tunku Abdul Rahman , Kampar , Malaysia
| | - Humaira Nisar
- a Faculty of Engineering and Green Technology , Universiti Tunku Abdul Rahman , Kampar , Malaysia
| | - Choon Aun Ng
- a Faculty of Engineering and Green Technology , Universiti Tunku Abdul Rahman , Kampar , Malaysia
| | - Po Kim Lo
- a Faculty of Engineering and Green Technology , Universiti Tunku Abdul Rahman , Kampar , Malaysia
| | - Vooi Voon Yap
- a Faculty of Engineering and Green Technology , Universiti Tunku Abdul Rahman , Kampar , Malaysia
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Khan MB, Nisar H, Ng CA, Yeap KH, Lai KC. Segmentation Approach Towards Phase-Contrast Microscopic Images of Activated Sludge to Monitor the Wastewater Treatment. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2017; 23:1130-1142. [PMID: 29212566 DOI: 10.1017/s1431927617012673] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Image processing and analysis is an effective tool for monitoring and fault diagnosis of activated sludge (AS) wastewater treatment plants. The AS image comprise of flocs (microbial aggregates) and filamentous bacteria. In this paper, nine different approaches are proposed for image segmentation of phase-contrast microscopic (PCM) images of AS samples. The proposed strategies are assessed for their effectiveness from the perspective of microscopic artifacts associated with PCM. The first approach uses an algorithm that is based on the idea that different color space representation of images other than red-green-blue may have better contrast. The second uses an edge detection approach. The third strategy, employs a clustering algorithm for the segmentation and the fourth applies local adaptive thresholding. The fifth technique is based on texture-based segmentation and the sixth uses watershed algorithm. The seventh adopts a split-and-merge approach. The eighth employs Kittler's thresholding. Finally, the ninth uses a top-hat and bottom-hat filtering-based technique. The approaches are assessed, and analyzed critically with reference to the artifacts of PCM. Gold approximations of ground truth images are prepared to assess the segmentations. Overall, the edge detection-based approach exhibits the best results in terms of accuracy, and the texture-based algorithm in terms of false negative ratio. The respective scenarios are explained for suitability of edge detection and texture-based algorithms.
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Affiliation(s)
- Muhammad Burhan Khan
- Faculty of Engineering and Green Technology,Universiti Tunku Abdul Rahman,Kampar,Perak 31900,Malaysia
| | - Humaira Nisar
- Faculty of Engineering and Green Technology,Universiti Tunku Abdul Rahman,Kampar,Perak 31900,Malaysia
| | - Choon Aun Ng
- Faculty of Engineering and Green Technology,Universiti Tunku Abdul Rahman,Kampar,Perak 31900,Malaysia
| | - Kim Ho Yeap
- Faculty of Engineering and Green Technology,Universiti Tunku Abdul Rahman,Kampar,Perak 31900,Malaysia
| | - Koon Chun Lai
- Faculty of Engineering and Green Technology,Universiti Tunku Abdul Rahman,Kampar,Perak 31900,Malaysia
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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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