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Ibrahim S, Abdul Wahab N. Optimizing neural network algorithms for submerged membrane bioreactor: A comparative study of OVAT and RSM hyperparameter optimization techniques. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2024; 89:1701-1724. [PMID: 38619898 DOI: 10.2166/wst.2024.099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Accepted: 03/10/2024] [Indexed: 04/17/2024]
Abstract
Hyperparameter tuning is an important process to maximize the performance of any neural network model. This present study proposed the factorial design of experiment for screening and response surface methodology to optimize the hyperparameter of two artificial neural network algorithms. Feed-forward neural network (FFNN) and radial basis function neural network (RBFNN) are applied to predict the permeate flux of palm oil mill effluent. Permeate pump and transmembrane pressure of the submerge membrane bioreactor system are the input variables. Six hyperparameters of the FFNN model including four numerical factors (neuron numbers, learning rate, momentum, and epoch numbers) and two categorical factors (training and activation function) are used in hyperparameter optimization. RBFNN includes two numerical factors such as a number of neurons and spreads. The conventional method (one-variable-at-a-time) is compared in terms of optimization processing time and the accuracy of the model. The result indicates that the optimal hyperparameters obtained by the proposed approach produce good accuracy with a smaller generalization error. The simulation results show an improvement of more than 65% of training performance, with less repetition and processing time. This proposed methodology can be utilized for any type of neural network application to find the optimum levels of different parameters.
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Affiliation(s)
- Syahira Ibrahim
- Faculty of Electrical Engineering, Universiti Teknologi Malaysia, Johor Bahru 81310, Malaysia
| | - Norhaliza Abdul Wahab
- Faculty of Electrical Engineering, Universiti Teknologi Malaysia, Johor Bahru 81310, Malaysia E-mail:
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Liu YJ. Investigation of factors affecting sodium alginate fouling mechanisms in a microfiltration process under non-constant-flux and non-constant-pressure conditions. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2023; 88:169-184. [PMID: 37452541 PMCID: wst_2023_206 DOI: 10.2166/wst.2023.206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/18/2023]
Abstract
Variations in transmembrane pressure and permeate flux are closely related to membrane fouling. In this study, a laboratory-scale submerged microfiltration system was used to investigate the influence of sodium alginate (SA) concentration and peristaltic pump rotation speed on the fouling under the conditions of (1) the same driving force and non-aerated-PAC, (2) different driving forces and non-aerated-PAC, and (3) different driving forces and aerated-PAC. The results showed that the normalized transmembrane pressure (TMP') increased linearly with decreasing normalized permeate flux (J') during the early microfiltration stage regardless of the operating conditions, indicating that the SA microfiltration process controlled by the peristaltic pump was non-constant-flux and non-constant-pressure. The latter filtration stage was considered constant-pressure filtration when 200-1,200 mg/L of SA was filtrated at the same rotation speed. During filtration of 800 mg/L of SA under the non-aerated-PAC condition, the later filtration stage was considered constant-pressure filtration when the peristaltic pump rotated at slower speeds of 15 and 30 rpm. This approached constant-flux filtration when the peristaltic pump rotated at faster speeds of 60 and 90 rpm, and PAC-aeration scouring was an effective measure for mitigating membrane fouling by SA.
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Affiliation(s)
- Ya-Juan Liu
- College of Chemistry and Chemical Engineering, Shanxi Datong University, Xingyun Street, Datong City 037009, China E-mail:
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Sohail N, Riedel R, Dorneanu B, Arellano-Garcia H. Prolonging the Life Span of Membrane in Submerged MBR by the Application of Different Anti-Biofouling Techniques. MEMBRANES 2023; 13:217. [PMID: 36837720 PMCID: PMC9962460 DOI: 10.3390/membranes13020217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Revised: 01/28/2023] [Accepted: 02/07/2023] [Indexed: 06/18/2023]
Abstract
The membrane bioreactor (MBR) is an efficient technology for the treatment of municipal and industrial wastewater for the last two decades. It is a single stage process with smaller footprints and a higher removal efficiency of organic compounds compared with the conventional activated sludge process. However, the major drawback of the MBR is membrane biofouling which decreases the life span of the membrane and automatically increases the operational cost. This review is exploring different anti-biofouling techniques of the state-of-the-art, i.e., quorum quenching (QQ) and model-based approaches. The former is a relatively recent strategy used to mitigate biofouling. It disrupts the cell-to-cell communication of bacteria responsible for biofouling in the sludge. For example, the two strains of bacteria Rhodococcus sp. BH4 and Pseudomonas putida are very effective in the disruption of quorum sensing (QS). Thus, they are recognized as useful QQ bacteria. Furthermore, the model-based anti-fouling strategies are also very promising in preventing biofouling at very early stages of initialization. Nevertheless, biofouling is an extremely complex phenomenon and the influence of various parameters whether physical or biological on its development is not completely understood. Advancing digital technologies, combined with novel Big Data analytics and optimization techniques offer great opportunities for creating intelligent systems that can effectively address the challenges of MBR biofouling.
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Affiliation(s)
- Noman Sohail
- Department of Biotechnology of Water Treatment, Brandenburg University of Technology Cottbus/Senftenberg, 03046 Cottbus, Germany
| | - Ramona Riedel
- Department of Biotechnology of Water Treatment, Brandenburg University of Technology Cottbus/Senftenberg, 03046 Cottbus, Germany
| | - Bogdan Dorneanu
- Department of Process and Plant Technology, Brandenburg University of Technology Cottbus/Senftenberg, 03046 Cottbus, Germany
| | - Harvey Arellano-Garcia
- Department of Process and Plant Technology, Brandenburg University of Technology Cottbus/Senftenberg, 03046 Cottbus, Germany
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Waheed H, Mehmood CT, Li Y, Du Y, Xiao Y. Biofouling control potential of quorum quenching anaerobes in lab-scale anaerobic membrane bioreactors: Foulants profile and microbial dynamics. CHEMOSPHERE 2023; 315:137760. [PMID: 36610508 DOI: 10.1016/j.chemosphere.2023.137760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 12/19/2022] [Accepted: 01/03/2023] [Indexed: 06/17/2023]
Abstract
Indigenously isolated anaerobes encoding four quorum quenching (QQ) enzymes were applied in immobilized- and bioaugmented forms for their implications on membrane foulants, microbial taxa, and biofouling control. Two identical anaerobic membrane bioreactors (AnMBRs) with different immobilizing media, i.e. silica-alginate (AnMBR-Si) and hollow fiber-alginate (AnMBR-Hf), were sequentially operated for two conventional and three QQ based phases. The synergistic addition of QQ anaerobes in free cells and the immobilized form prolonged the membrane filtration operation by 172 ± 29% and 284 ± 12% in AnMBR-Si and AnMBR-Hf, respectively. Biocake with low surface coverage was prominent during QQ application compared to conventional phases. Despite the better control of AHLs (3OC6-, C6-, 3OC8, C8, and C10-HSL) and AI-2 at various points of QQ phases, the QQ consortium could not maintain a low concentration of signals for longer period. Therefrom, quenching of targeted signal molecules instigate the dominance of microbial species bearing non-targeted quorum sensing mechanism. The QQ significantly altered the biofilm-forming community in mixed liquor, while the members with robust signal transduction systems became dominant to counteract the QQ mechanism and were the ultimate cause of biofouling. The improved methane content in biogas and increased methanogens composition during QQ phases demonstrated the synergism of exogenous and immobilized QQ as the most viable option for long-term AnMBR operation.
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Affiliation(s)
- Hira Waheed
- Department of Civil and Environmental Engineering, Shantou University, Shantou, Guangdong, 515063, China
| | - Ch Tahir Mehmood
- Department of Chemical Engineering, Guangdong Technion - Israel Institute of Technology, Shantou, Guangdong, 515063, China
| | - Yiwei Li
- Department of Civil and Environmental Engineering, Shantou University, Shantou, Guangdong, 515063, China
| | - Ying Du
- Department of Civil and Environmental Engineering, Shantou University, Shantou, Guangdong, 515063, China
| | - Yeyuan Xiao
- Department of Civil and Environmental Engineering, Shantou University, Shantou, Guangdong, 515063, China.
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The impact of powdered activated carbon types on membrane anti-fouling mechanism in membrane bioreactors. Appl Microbiol Biotechnol 2022; 106:7337-7345. [PMID: 36149455 DOI: 10.1007/s00253-022-12186-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 09/07/2022] [Accepted: 09/18/2022] [Indexed: 11/02/2022]
Abstract
Dosing powdered activated carbon (PAC) has been proven to be an economical and effective method to mitigate membrane fouling. However, the effects of pretreated PAC with different redox properties on membrane fouling still need to be further investigated. Here, the impact of commercial PAC, oxidized-PAC, and reduced-PAC on membrane fouling was investigated in membrane bioreactors (MBRs). Surprisingly, the filtration cycles were extended from 12-36 h to 132-156 h only by dosing reduced-PAC and commercial PAC with a finial dosage of 3 g/L, which were provided with reductive properties. However, few improvements of filtration cycle (less than 50 h) were achieved by dosing oxidized-PAC in the same dosage, which had the same adsorption performance as reduced-PAC and commercial PAC. The biomass and foulant concentration suggested that the enhanced anti-fouling performances by PAC with reductive properties were mainly attributed to the reduction of extracellular polymer substances (EPS) and soluble microbial products (SMP) content in the bulk solutions after 14 days of continuous operation. The model foulant degradation tests and the confocal laser scanning microscope (CLSM) images of activated sludge further demonstrated that PAC with reductive properties directly affected the microbial activities by controlling the EPS and SMP concentrations in the bulk solution, thereby suppressing membrane fouling. Such a finding provides new insights into anti-fouling mechanisms that the redox properties of PAC played a decisive role in membrane fouling mitigation, and also provides a strategy to prolong the anti-fouling effects by restoring the reductive properties of PAC. KEY POINTS: • The anti-fouling mechanisms of PAC with reductive property were investigated. • Reductive property was the main reason for fouling control instead of adsorption. • PAC with reductive property hindered the sludge activity to produce fewer foulants.
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Liu YJ. Mitigation of membrane fouling of alginate with combined actions of aeration and powdered activated carbon: Fouling behaviors and mechanisms. WATER ENVIRONMENT RESEARCH : A RESEARCH PUBLICATION OF THE WATER ENVIRONMENT FEDERATION 2022; 94:e10748. [PMID: 35703107 DOI: 10.1002/wer.10748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 05/03/2022] [Accepted: 05/25/2022] [Indexed: 06/15/2023]
Abstract
A laboratory-scale flat-sheet ceramic microfiltration membrane system was developed to investigate the membrane fouling behaviors and mechanisms of sodium alginate (SA) in the presence of aeration and powdered activated carbon (PAC). When the SA concentration increased from 20 to 500 mg/L, the permeate flux decreased by 81.7%, and the transmembrane pressure (TMP) and resistance increased 1.7 and 24.5 times, respectively. At an SA concentration of 500 mg/L, it was found that the membrane fouling tended to decrease with the increase in the aeration rate, indicating high control of the fouling by air scouring, while PAC-aeration scouring produced a significant improvement in the permeate flux with substantially reduced fouling. In the microfiltration of 500 mg/L SA at an air flow rate of 2.2 L/min and PAC concentrations of 40, 100, and 250 mg/L, the flux increased by 179.3%, 238.0%, and 302.7%, the TMP decreased by 32.6%, 34.8%, and 45.7%, and the cake and pore blocking resistance decreased by 78.0%, 85.1%, and 87.9%, respectively, compared to the corresponding values without PAC-aeration scouring. Intermediate blocking and complete blocking models were confirmed to elucidate the effect of aeration scouring and PAC-aeration scouring on the mitigation of membrane fouling by SA. PRACTITIONER POINTS: Air scouring was effective at mitigating membrane fouling of sodium alginate. The addition of PAC could alleviate membrane fouling of SA. Synergistic scouring by aeration and PAC offers a promising means for more-efficient and cost-effective control of membrane fouling. The fouling mechanisms in various scenarios were elucidated.
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Affiliation(s)
- Ya-Juan Liu
- College of Chemistry and Chemical Engineering, Shanxi Datong University, Datong City, P.R. China
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Evaluating the impacts of a high concentration of powdered activated carbon in a ceramic membrane bioreactor: Mixed liquor properties, hydraulic performance and fouling mechanism. J Memb Sci 2020. [DOI: 10.1016/j.memsci.2020.118561] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Arabi S, Pellegrin ML, Aguinaldo J, Sadler ME, McCandless R, Sadreddini S, Wong J, Burbano MS, Koduri S, Abella K, Moskal J, Alimoradi S, Azimi Y, Dow A, Tootchi L, Kinser K, Kaushik V, Saldanha V. Membrane processes. WATER ENVIRONMENT RESEARCH : A RESEARCH PUBLICATION OF THE WATER ENVIRONMENT FEDERATION 2020; 92:1447-1498. [PMID: 32602987 DOI: 10.1002/wer.1385] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 06/20/2020] [Indexed: 06/11/2023]
Abstract
This literature review provides a review for publications in 2018 and 2019 and includes information membrane processes findings for municipal and industrial applications. This review is a subsection of the annual Water Environment Federation literature review for Treatment Systems section. The following topics are covered in this literature review: industrial wastewater and membrane. Bioreactor (MBR) configuration, membrane fouling, design, reuse, nutrient removal, operation, anaerobic membrane systems, microconstituents removal, membrane technology advances, and modeling. Other sub-sections of the Treatment Systems section that might relate to this literature review include the following: Biological Fixed-Film Systems, Activated Sludge, and Other Aerobic Suspended Culture Processes, Anaerobic Processes, and Water Reclamation and Reuse. This publication might also have related information on membrane processes: Industrial Wastes, Hazardous Wastes, and Fate and Effects of Pollutants.
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Affiliation(s)
| | | | | | | | | | | | - Joseph Wong
- Brown and Caldwell, Walnut Creek, California, USA
| | | | | | | | - Jeff Moskal
- Suez Water Technologies & Solutions, Oakville, ON, Canada
| | | | | | - Andrew Dow
- Donohue and Associates, Chicago, Illinois, USA
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