1
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Khalaf MM, Gouda M, Abou Taleb MF, Heakal FET, Abd El-Lateef HM. Fabrication of smart nanogel based on carrageenan and green coffee extract as a long-term antifouling agent to improve biofilm prevention in food production. Food Chem 2024; 461:140719. [PMID: 39146677 DOI: 10.1016/j.foodchem.2024.140719] [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: 03/27/2024] [Revised: 07/22/2024] [Accepted: 07/29/2024] [Indexed: 08/17/2024]
Abstract
This study investigates the extract of the bioactive compounds from green coffee extract (GCE) and the loading of two different concentrations of GCE (1% and 2%) onto carrageenan nanogels (CAR NGs) to compare their antibacterial and antibiofilm effects with unloaded nanogels (NGs). The bioactive compounds of GCE were characterized using GC-MS analysis. The GCE1 and GCE2 were successfully deposited onto the surface of CAR NGs. The antibacterial and antibiofilm potential of prepared NGs were conducted against some foodborne pathogens (E. coli O157, Salmonella enterica, Staphylococcus aureus, and Listeria monocytogenes). The results of GC-MS analysis indicated that there were identified 16 bioactive compounds in GCE, including caffeine (36.27%), Dodemorph (9.04%), and D-Glycero-d-ido-heptose (2.44%), contributing to its antimicrobial properties. The antibacterial coatings demonstrated a notable antimicrobial effect, showing zone of inhibition (ZOI) diameters of up to 37 mm for GCE2 loaded CAR NGs. The minimum inhibitory concentration (MIC) values for GCE2 loaded CAR NGs were 80 ppm for E. coli O157, and 120 ppm for S. enterica, S. aureus, and L. monocytogenes, achieving complete bacterial inactivation within 10-15 min of exposure. Both GCE1 and GCE2 loaded CAR NGs significantly reduced biofilm cell densities on stainless steel (SS) materials for E. coli O157, S. enterica, S. aureus, and L. monocytogenes, with reductions ranging from 60% to 95%. Specifically, biofilm densities were reduced by up to 95% for E. coli O157, 89% for S. enterica, 85% for S. aureus, and 80% for L. monocytogenes. Results of the toxicity evaluation indicated that the NGs were non-toxic and biocompatible, with predicted EC50 values proved their biocompatibility and safety. These results recommended that GCE loaded CAR NGs are promising as natural antimicrobial agents for enhancing food safety and extending shelf life. Further, the study concluded that incorporating GCE into CAR NGs is an effective strategy for developing sustainable antimicrobial coatings for the food industry and manufacturing.
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Affiliation(s)
- Mai M Khalaf
- Department of Chemistry, College of Science, King Faisal University, Al-Ahsa 31982, Saudi Arabia; Department of Chemistry, Faculty of Science, Sohag University, Sohag 82524, Egypt.
| | - Mohamed Gouda
- Department of Chemistry, College of Science, King Faisal University, Al-Ahsa 31982, Saudi Arabia.
| | - Manal F Abou Taleb
- Department of Chemistry, College of Science and Humanities, Prince Sattam Bin Abdulaziz University, Al-Kharj 11942, Saudi Arabia
| | | | - Hany M Abd El-Lateef
- Department of Chemistry, College of Science, King Faisal University, Al-Ahsa 31982, Saudi Arabia; Department of Chemistry, Faculty of Science, Sohag University, Sohag 82524, Egypt
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2
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Qi J, Gao T, Zhou Q, Huang S, Lin J, Xu R, Tang CY, Meng F. Activating Biocake Communities Retards Jumps of Transmembrane Pressure in Membrane Bioreactors. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024. [PMID: 39078411 DOI: 10.1021/acs.est.4c03038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/31/2024]
Abstract
Sudden jump of transmembrane pressure (TMP) in membrane bioreactors (MBRs), associated with abrupt aggravation of membrane fouling, limits practical applications of MBRs and calls for effective mitigation strategies. While the TMP jump is generally related to the bacterial activity of biocakes, the mechanisms underlying the TMP jump remain unclear. Herein, we conducted various backwash protocols with different nutrient (e.g., nitrate and sodium acetate) loadings on fouled membranes in MBRs to reveal the critical role of bacterial activity of biocakes for the TMP jump. The filtration tests showed a lower TMP jump rate for the membrane backwashed with a nutrient solution (a mixture of 180 mg/L NaNO3 and 200 mg/L NaAc, averaged at 1.40 kPa/d) than that backwashed with tap water (averaged at 3.56 kPa/d), implying that TMP jump could be efficiently mitigated by providing sufficient nutrients to biocake bacteria. The characterization of biocakes showed that high-nutrient solution backwash considerably increased bacterial viability and activity, while considerably reducing biomolecule accumulation on membranes. The keystone taxa (e.g., g_Aeromonas and o_Chitinophagaceae) in the network of nutrient-enriched biocake communities were involved in nitrate reduction and biomolecule degradation. Ecological null model analyses revealed that the deterministic manner mainly shaped biocake communities with high-nutrient availability. Overall, this study highlights the significance of the bacterial activity of biocakes for TMP development and provides potential alternatives for controlling membrane fouling.
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Affiliation(s)
- Ji Qi
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, PR China
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510275, PR China
| | - Tianyu Gao
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, PR China
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510275, PR China
| | - Qicheng Zhou
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, PR China
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510275, PR China
| | - Siqian Huang
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, PR China
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510275, PR China
| | - Jingtong Lin
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, PR China
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510275, PR China
| | - Ronghua Xu
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, PR China
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510275, PR China
| | - Chuyang Y Tang
- Department of Civil Engineering, University of Hong Kong, Pokfulam, Hong Kong
| | - Fangang Meng
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, PR China
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510275, PR China
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Zhao B, Yang G, Xie Z, Zhang N, Xia J, Liu X, Wang D, Wang P, Tang L. Efficient degradation of venlafaxine using intimately coupled high-active crystal facets exposed TiO 2 and biodegradation system: Kinetic studies, biofilm stress behavior and transformation mechanism. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 360:121159. [PMID: 38759549 DOI: 10.1016/j.jenvman.2024.121159] [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: 12/19/2023] [Revised: 04/15/2024] [Accepted: 05/10/2024] [Indexed: 05/19/2024]
Abstract
Intimately coupled photocatalysis and biodegradation (ICPB) system is a potential wastewater treatment technology, of which TiO2-based ICPB system has been widely studied. There are many ways to improve the degradation efficiency of the ICPB process, but no crystal facet engineering method has been reported yet. In this work, a new ICPB system coated with NaF-TiO2 exposing high energy facets was designed to degrade biorecalcitrant psychotropic drug - venlafaxine (VNF). Initially, the TiO2 crystal surface was modified with NaF, resulting in the formation of NaF-TiO2 with a 14.4% increase in the exposure ratio of (001). The contribution rate of ·OH was increased by 9.5%, and the contribution rate of h+ was increased by 33.2%. Next, NaF-TiO2 was loaded onto the surface of the sponge carrier, and then the ICPB system was constructed after about 15 days of biofilm formation. After the ICPB system was acclimated with VNF, the removal rate of COD decreased significantly (the lowest was 62.7%), but that of ammonia nitrogen remained at 50.5 ± 6.0% and the extracellular polymeric substance (EPS) secretion increased by 84.1 mg/g VSS. According to the high throughput results, at the phylum level, Proteobacteria and Chloroflexi together maintain the nitrogen removal capability and structural stability of the ICPB system. The relative abundance of Bacteroidota was significantly increased by 14.2%, suggesting that there may be some correlation between Bacteroidota and certain metabolites of the anti-depressant active ingredients. At the genus level, the Thauera (3.1%∼11.5%) is the major bacterial group that secretes EPS, protecting biofilm against external influences. Most of the changes in microorganisms are consistent with the decontamination properties and macroscopic appearance of EPS in the ICPB system. Finally, the degradation efficiency of ICPB system for VNF was investigated (92.7 ± 3.8%) and it was mostly through hydroxylation and demethylation pathways, with more small molecular products detected, providing the basis for biological assimilation of VNF. Collectively, the NaF-TiO2 based ICPB system would be lucrative for the future degradation of venlafaxine.
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Affiliation(s)
- Bo Zhao
- College of Biological and Environmental Sciences, Zhejiang Wanli University, Ningbo, 315100, PR China
| | - Guojing Yang
- College of Biological and Environmental Sciences, Zhejiang Wanli University, Ningbo, 315100, PR China; College of Environmental Science and Engineering and Key Laboratory of Environmental Biology and Pollution Control (Ministry of Education), Hunan University, Changsha, 410082, PR China.
| | - Zhouyun Xie
- College of Biological and Environmental Sciences, Zhejiang Wanli University, Ningbo, 315100, PR China
| | - Ni Zhang
- College of Biological and Environmental Sciences, Zhejiang Wanli University, Ningbo, 315100, PR China; College of Environmental Science and Engineering and Key Laboratory of Environmental Biology and Pollution Control (Ministry of Education), Hunan University, Changsha, 410082, PR China
| | - Jingfen Xia
- College of Biological and Environmental Sciences, Zhejiang Wanli University, Ningbo, 315100, PR China.
| | - Xuran Liu
- College of Environmental Science and Engineering and Key Laboratory of Environmental Biology and Pollution Control (Ministry of Education), Hunan University, Changsha, 410082, PR China
| | - Dongbo Wang
- College of Environmental Science and Engineering and Key Laboratory of Environmental Biology and Pollution Control (Ministry of Education), Hunan University, Changsha, 410082, PR China
| | - Peier Wang
- College of Biological and Environmental Sciences, Zhejiang Wanli University, Ningbo, 315100, PR China
| | - Li Tang
- College of Biological and Environmental Sciences, Zhejiang Wanli University, Ningbo, 315100, PR China
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4
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Li J, Tang L, Zhang Y, Gao M, Wang S, Wang X. Hydrodynamic cultivation of aeration-free oxygenic photogranules is favored by sufficient amounts of organic carbon. BIORESOURCE TECHNOLOGY 2024; 401:130736. [PMID: 38670289 DOI: 10.1016/j.biortech.2024.130736] [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: 01/22/2024] [Revised: 04/09/2024] [Accepted: 04/23/2024] [Indexed: 04/28/2024]
Abstract
Oxygenic photogranules (OPGs) have great potential for the aeration-free treatment of various wastewater, however, the effects of wastewater carbon composition on OPGs remain unknown. This study investigated the hydrodynamic photogranulation in three types of wastewater with the same total carbon concentration but different inorganic/organic carbon compositions, each operated at two replicated reactors. Results showed that photogranulation failed in reactors fed with only inorganic carbon. In reactors with equal inorganic and organic carbon, loose-structured OPGs formed but then disintegrated. Comparatively, reactors treating organic carbon-based wastewater obtained regular and dense OPGs with better settleability, lower effluent turbidity, excellent structural stability, and higher carbon assimilation rate. Sufficient amounts of organic carbon were crucial for the formation and stability of OPGs as they promoted the secretion of extracellular polymeric substances (EPS) and the growth of filamentous cyanobacteria. This study provides a basis for the startup of OPGs process and facilitates its large-scale application.
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Affiliation(s)
- Junrong Li
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, Shandong Key Laboratory of Environmental Processes and Health, School of Environmental Science and Engineering, Shandong University, Qingdao 266237, China
| | - Liaofan Tang
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, Shandong Key Laboratory of Environmental Processes and Health, School of Environmental Science and Engineering, Shandong University, Qingdao 266237, China
| | - Yuqing Zhang
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, Shandong Key Laboratory of Environmental Processes and Health, School of Environmental Science and Engineering, Shandong University, Qingdao 266237, China
| | - Mingming Gao
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, Shandong Key Laboratory of Environmental Processes and Health, School of Environmental Science and Engineering, Shandong University, Qingdao 266237, China
| | - Shuguang Wang
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, Shandong Key Laboratory of Environmental Processes and Health, School of Environmental Science and Engineering, Shandong University, Qingdao 266237, China; Weihai Research Institute of Industrial Technology of Shandong University, Weihai 264209, China
| | - Xinhua Wang
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, Shandong Key Laboratory of Environmental Processes and Health, School of Environmental Science and Engineering, Shandong University, Qingdao 266237, China.
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5
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Mokhtariazar A, Hassani AH, Borghei M, Massoudinejad M. A comparative study on performance of the conventional and fixed-bed membrane bioreactors for treatment of Naproxen from pharmaceutical wastewater. Sci Rep 2024; 14:9944. [PMID: 38688946 PMCID: PMC11061303 DOI: 10.1038/s41598-024-52872-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Accepted: 01/24/2024] [Indexed: 05/02/2024] Open
Abstract
Here, a comparative study was designed to survey the treatment efficiency of pharmaceutical wastewater containing Naproxen by Membrane bioreactor (MBR) and MBR with fixed-bed packing media (FBMBR). To this end, the performance of MBR and FBMBR in different aeration conditions including average DO (1.9-3.8 mg/L), different organic loading (OLR) (0.86, 1.14 and 1.92 kg COD per cubic meter per day), and Naproxen removal efficiency. The BOD5 removal efficiency, effluent quality and membrane fouling were monitored within 140 days. The results obtained from the present study indicated that COD removal efficiency for FBMBR (96.46%) was higher than that for MBR (95.33%). In addition, a high COD removal efficiency was experienced in both MBR and FBMBR in operational conditions 3 and 4, even where OLR increased from 1.14 to 1.92 kgCOD/m3 d and DO decreased from 4 to < 1 mg/L. Furthermore, the higher Naproxen removal efficiency was observed in FBMBR (94.17%) compared to that for MBR (92.76%). Therefore, FBMBR is a feasible and promising method for efficient treatment of pharmaceuptical wastewater with high concentrations of emerging contaminant, especially, the Naproxen.
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Affiliation(s)
- Akbar Mokhtariazar
- Department of Environmental Engineering, Islamic Azad University, West Tehran Branch, Tehran, Iran
| | - Amir Hessam Hassani
- Department of Environmental Engineering, Faculty of Natural Resources and Environment, Science and Research Branch, Islamic Azad University, Tehran, Iran.
| | - Mahdi Borghei
- Department of Biochemical Engineering and Environmental Control Research Center, Sharif University of Technology, Tehran, Iran
| | - Mohamadreza Massoudinejad
- Department of Environmental Health Engineering, School of Public Health and Safety, Shahid Behashti University of Medical Sciences, Tehran, Iran
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6
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Gouda M, Khalaf MM, Abou Taleb MF, Abd El-Lateef HM. Fabrication of silver nanoparticles loaded acacia gum/chitosan nanogel to coat the pipe surface for sustainable inhibiting microbial adhesion and biofilm growth in water distribution systems. Int J Biol Macromol 2024; 262:130085. [PMID: 38346613 DOI: 10.1016/j.ijbiomac.2024.130085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2023] [Revised: 02/01/2024] [Accepted: 02/08/2024] [Indexed: 02/17/2024]
Abstract
Biofilm formation on the inner surfaces of pipes poses significant threats to water distribution systems, increasing maintenance costs and public health risks. To address this immense issue, we synthesized a nanogel formulation comprising acacia gum (AG) and chitosan (Cs), loaded with varying concentrations of silver nanoparticles (AgNPs), for using as an antimicrobial coating material. AgNPs were synthesized using AG as a reducing and stabilizing agent, exhibiting absorbance at 414 nm. The preparation of AgNPs was proved using TEM. Bactericidal efficacy was assessed against E. coli, Klebsiella pneumoniae, Enterococcus faecalis, and Bacillus subtilis. Using the dipping coating method, two pipe materials (polypropylene (PP) and ductile iron (DI)) were successfully coated. Notably, AgNPs2@AGCsNG nanogel exhibited potent antibacterial action against a wide range of pathogenic bacteria. Toxicity tests confirmed nanogel safety, suggesting broad applications. High EC50% values underscored their non-toxic nature. This research proposes an effective strategy for biofilm prevention in water systems, offering excellent antibacterial properties and biocompatibility. AG and Cs nanogels loaded with AgNPs promise to enhance water quality, reduce maintenance prices, and protect human public health in water distribution networks.
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Affiliation(s)
- Mohamed Gouda
- Department of Chemistry, College of Science, King Faisal University, Al-Ahsa 31982, Saudi Arabia.
| | - Mai M Khalaf
- Department of Chemistry, College of Science, King Faisal University, Al-Ahsa 31982, Saudi Arabia; Department of Chemistry, Faculty of Science, Sohag University, Sohag 82524, Egypt
| | - Manal F Abou Taleb
- Department of Chemistry, College of Science and Humanities, Prince Sattam Bin Abdulaziz University, Al-Kharj 11942, Saudi Arabia
| | - Hany M Abd El-Lateef
- Department of Chemistry, College of Science, King Faisal University, Al-Ahsa 31982, Saudi Arabia; Department of Chemistry, Faculty of Science, Sohag University, Sohag 82524, Egypt.
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7
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Liu Z, Pang H, Yi K, Wang X, Zhang W, Zhang C, Liu S, Gu Y, Huang J, Shi L. Isolation and application of Bacillus thuringiensis LZX01: Efficient membrane biofouling mitigation function and anti-toxicity potential. BIORESOURCE TECHNOLOGY 2024; 394:130272. [PMID: 38185444 DOI: 10.1016/j.biortech.2023.130272] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 12/27/2023] [Accepted: 12/27/2023] [Indexed: 01/09/2024]
Abstract
Significant progress has been made in mitigating membrane biofouling by microbial quorum quenching (QQ). More efficient and survivable QQ strains need to be discovered. A new strain named Bacillus thuringiensis LZX01 was isolated in this study using a low carbon source concentration "starving" method from a membrane bioreactor (MBR). LZX01 secreted intracellular lactonase to enable QQ behavior and was capable of degrading 90 % of C8-HSL (200 ng/mL) within 30 min, which effectively delayed biofouling by inhibiting the growth of bacteria associated with biofouling and improving the hydrophilicity of bound extracellular polymeric substances. As a result, the membrane biofouling rate of MBR adding LZX01 was four times slower than that of the control MBR. Importantly, LZX01 maintains its QQ activity even in environments contaminated with typical toxic pollutants. Therefore, with high efficiency, toxicity resistance, and easy culture, LZX01 holds great potential and significant promise for biofouling control applications.
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Affiliation(s)
- Zhexi Liu
- College of Environmental Science and Engineering, Hunan University, Changsha, Hunan 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, Hunan 410082, China
| | - Haoliang Pang
- College of Environmental Science and Engineering, Hunan University, Changsha, Hunan 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, Hunan 410082, China
| | - Kaixin Yi
- College of Environmental Science and Engineering, Hunan University, Changsha, Hunan 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, Hunan 410082, China
| | - Xia Wang
- College of Environmental Science and Engineering, Hunan University, Changsha, Hunan 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, Hunan 410082, China
| | - Wei Zhang
- College of Environmental Science and Engineering, Hunan University, Changsha, Hunan 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, Hunan 410082, China
| | - Chenyu Zhang
- College of Environmental Science and Engineering, Hunan University, Changsha, Hunan 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, Hunan 410082, China
| | - Si Liu
- College of Environmental Science and Engineering, Hunan University, Changsha, Hunan 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, Hunan 410082, China
| | - Yanling Gu
- College of Materials Science and Engineering, Changsha University of Science and Technology, Changsha 410114, China
| | - Jinhui Huang
- College of Environmental Science and Engineering, Hunan University, Changsha, Hunan 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, Hunan 410082, China.
| | - Lixiu Shi
- School of Hydraulic and Environmental Engineering, Changsha University of Science & Technology, Changsha 410114,China; Key Laboratory of Dongting Lake Aquatic Eco-Environmental Control and Restoration of Hunan Province, Changsha 410114, China.
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8
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El-Newehy MH, Aldalbahi A, Thamer BM, Hameed MMA. Establishment and inactivation of mono-species biofilm in a semipilot-scale water distribution system using nanocomposite of silver nanoparticles/montmorillonite loaded cationic chitosan. Int J Biol Macromol 2024; 258:128874. [PMID: 38128797 DOI: 10.1016/j.ijbiomac.2023.128874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 12/10/2023] [Accepted: 12/16/2023] [Indexed: 12/23/2023]
Abstract
This study presents a novel approach in the synthesis and characterization of nanocomposites comprising cationic chitosan (CCS) blended with varying concentrations of silver nanoparticles/montmorillonite (AgNPs/MMT). AgNPs/MMT was synthesized using soluble starch as a reducing and stabilizing agent. Subsequently, nanocomposites, namely CCS/AgMMT-0, CCS/AgMMT-0.5, CCS/AgMMT-1.5, and CCS/AgMMT-2.5, were developed by blending 2.5 g of CCS with 0, 0.5, 1.5, and 2.5 g of AgNPs/MMT, respectively, and the corresponding nanocomposites were prepared using ball milling technique. Transmission electron microscopy (TEM) analysis revealed the formation of nanocomposites that exhibiting nearly spherical morphologies. Dynamic light scattering (DLS) measurements displayed average particle sizes of 1183 nm, 131 nm, 140 nm, and 188 nm for CCS/AgMMT-0, CCS/AgMMT-0.5, CCS/AgMMT-1.5, and CCS/AgMMT-2.5, respectively. The narrow polydispersity index (~0.5) indicated uniform particle size distributions across the nanocomposites, affirming monodispersity. Moreover, the zeta potential values exceeding 30 mV across all nanocomposites that confirmed their stability against agglomeration. Notably, CCS/AgMMT-2.5 nanocomposite exhibited potent antibacterial and antibiofilm properties against diverse pipeline materials. Findings showed that after 15 days of incubation, the highest populations of biofilm cells, Pseudomonas aeruginosa biofilm, developed over UPVC, MDPE, DCI, and SS, with corresponding HPCs of 4.79, 6.38, 8.81, and 7.24 CFU/cm2. The highest cell densities of Enterococcus faecalis biofilm in the identical situation were 4.19, 5.89, 8.12, and 6.9 CFU/cm2. The nanocomposite CCS/AgMMT-2.5 exhibited the largest measured zone of inhibition (ZOI) against both P. aeruginosa and E. faecalis, with measured ZOI values of 19 ± 0.65 and 17 ± 0.21 mm, respectively. Remarkably, the research indicates that the youngest biofilm exhibited the most notable rate of inactivation when exposed to a dose of 150 mg/L, in comparison to the mature biofilm. These such informative findings could offer valuable insights into the development of effective antibiofilm agents and materials applicable in diverse sectors such as water treatment facilities, medical devices, and industrial pipelines.
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Affiliation(s)
- Mohamed H El-Newehy
- Department of Chemistry, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia.
| | - Ali Aldalbahi
- Department of Chemistry, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
| | - Badr M Thamer
- Department of Chemistry, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
| | - Meera Moydeen Abdul Hameed
- Department of Chemistry, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
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9
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Homyok P, Rongsayamanont C, Wongkiew S, Limpiyakorn T. Sludge floc characteristics and microbial community in high-rate activated sludge and high-rate membrane bioreactor for organic recovery. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 906:167387. [PMID: 37777134 DOI: 10.1016/j.scitotenv.2023.167387] [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: 06/07/2023] [Revised: 09/24/2023] [Accepted: 09/24/2023] [Indexed: 10/02/2023]
Abstract
High-rate activated sludge (HRAS) and high-rate membrane bioreactor (HRMBR) are considered as potential processes for organic recovery through bioflocculation and biosorption of particulate COD and colloidal COD with sludge flocs. In this study, bioflocculation and biosorption, in terms of sludge floc characteristics and microbial community, in HRAS and HRMBR was investigated in relation to organic recovery performance for low strength wastewater treatment. HRAS and HRMBR were operated at two different solids retention times (SRTs) of 2 and 0.8 days. Reducing the SRT of HRAS from 2.0 to 0.8 days resulted in failure in total COD (tCOD) removal efficiency (from 79 ± 2 to 34 ± 13 %) and lowering organic recovery (from 40.8 to 15.7 %). This contrasted with HRMBR, which showed high tCOD removal efficiency (84 ± 2 and 84 ± 1 %) and organic recovery (43.4 and 46.3 %) at both SRTs of 2.0 and 0.8 days. Analysis of sludge floc characteristics showed that the lower organic recovery of the HRAS operated at an SRT of 0.8 days could be associated with poor bioflocculation and biosorption, as evidenced by relatively larger floc size, higher extracellular polymeric substance, higher protein/polysaccharide ratio, and higher zeta potential value of the sludge. These characteristics were in contrast to the HRMBR operated at an SRT of 0.8 days, that exhibited the highest organic recovery among the reactors studied. The microbial taxa Bdellovibrio, Clostridium sensu stricto 9, Hyphomicrobium, and Ideonella could play a role in the poor bioflocculation and biosorption in HRAS. Rhodanobacter, Enterobacter, Terrimonas, Nakamurella, and Mizugakiibacter may be associated with bioflocculation and biosorption and organic recovery in HRMBR. The results of this study enhanced our understanding on the relationships between the microbial community, sludge floc characteristics, and organic recovery performance of HRAS and HRMBR for future optimization of the systems.
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Affiliation(s)
- Pratamaporn Homyok
- Department of Environmental Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok 10330, Thailand
| | - Chaiwat Rongsayamanont
- Faculty of Environmental Management, Prince of Songkla University, Songkhla 90110, Thailand
| | - Sumeth Wongkiew
- Department of Environmental Science, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand; Waste Utilization and Ecological Risk Assessment Research Unit, Chulalongkorn University, Bangkok 10330, Thailand
| | - Tawan Limpiyakorn
- Department of Environmental Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok 10330, Thailand; Biotechnology for Wastewater Engineering Research Unit, Chulalongkorn University, Bangkok 10330, Thailand.
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10
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Wang H, Qiu C, Bian S, Zheng L, Chen Y, Song Y, Fang C. The effects of microplastics and nanoplastics on nitrogen removal, extracellular polymeric substances and microbial community in sequencing batch reactor. BIORESOURCE TECHNOLOGY 2023; 379:129001. [PMID: 37011839 DOI: 10.1016/j.biortech.2023.129001] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Revised: 03/17/2023] [Accepted: 03/30/2023] [Indexed: 05/03/2023]
Abstract
Wastewater treatment plants can be nanoplastics (NPs) and microplastics (MPs) sinks and sources. The effects of NPs and MPs on nitrogen removal and extracellular polymeric substances (EPS) during activated sludge process need further investigation. Results showed that polystyrene NPs (NPS) and 100 mg/L polystyrene MPs (MPS) decreased the specific nitrate reduction rate, resulting in nitrate accumulation. The negative effects on functional genes involved in denitrification (narG, napA, nirS and nosZ) were the main mechanism. NPS stimulated EPS secretion, but MPS inhibited it. NPS and MPS increased the ratio of protein to polysaccharide except for 10 mg/L MPS and changed the secondary structure of protein in EPS, affecting flocculation ability of activated sludge. The changes of microbial abundance in activated sludge could be the main factor to the alterations of EPS and nitrogen removal. These results may facilitate understanding the impacts of NPs and MPs on wastewater treatment processes.
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Affiliation(s)
- Hua Wang
- School of Civil Engineering and Architecture, Zhejiang University of Science and Technology, Hangzhou 310023, Zhejiang, China; Key Laboratory of Recycling and Eco-treatment of Waste Biomass of Zhejiang Province, Zhejiang University of Science and Technology, Hangzhou 310023, Zhejiang, China
| | - Cheng Qiu
- School of Civil Engineering and Architecture, Zhejiang University of Science and Technology, Hangzhou 310023, Zhejiang, China
| | - Shaochen Bian
- School of Civil Engineering and Architecture, Zhejiang University of Science and Technology, Hangzhou 310023, Zhejiang, China
| | - Lei Zheng
- School of Civil Engineering and Architecture, Zhejiang University of Science and Technology, Hangzhou 310023, Zhejiang, China
| | - Yongmin Chen
- School of Civil Engineering and Architecture, Zhejiang University of Science and Technology, Hangzhou 310023, Zhejiang, China; Key Laboratory of Recycling and Eco-treatment of Waste Biomass of Zhejiang Province, Zhejiang University of Science and Technology, Hangzhou 310023, Zhejiang, China
| | - Yali Song
- School of Civil Engineering and Architecture, Zhejiang University of Science and Technology, Hangzhou 310023, Zhejiang, China; Key Laboratory of Recycling and Eco-treatment of Waste Biomass of Zhejiang Province, Zhejiang University of Science and Technology, Hangzhou 310023, Zhejiang, China.
| | - Chengran Fang
- College of Civil Engineering, Zhejiang University of Technology, Hangzhou 310023, Zhejiang, China
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11
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Zuo Y, Shao Y, Wang L, Sun Y, An Y, Jiang LM, Yu N, Hao R, Zhou C, Tao J, Zhou Z. Simultaneous sludge minimization and membrane fouling mitigation in membrane bioreactors by using a microaerobic - Settling pretreatment module. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 328:116977. [PMID: 36495823 DOI: 10.1016/j.jenvman.2022.116977] [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: 10/15/2022] [Revised: 12/02/2022] [Accepted: 12/03/2022] [Indexed: 06/17/2023]
Abstract
Membrane fouling is the major obstacle for membrane bioreactors operated at a long sludge retention time to reduce sludge production. In this study, a sludge process reduction (SPR) module, consisting of a microaerobic tank and a settler, was inserted before an anoxic/oxic MBR (AO-MBR) to achieve dual objectives of fouling alleviation and sludge reduction. Three SPR-MBRs were operated to investigate influences of sludge recirculation ratios from the SPR settler to the microaerobic tank on process performance. Compared to AO-MBR, the SPR-MBRs reduced sludge production by 43.1-56.4% by maintaining sludge retention times above 175 d, and decreased foulant layer resistance and pore clogging resistance. Inserting SPR reduced the accumulation of dissolved organic matters and extracellular polymeric substances, enlarged sludge flocs, and decreased sludge viscoelasticity. However, increasing RSPR stimulated outward diffusion of extracellular polymeric substances and increased sludge viscosity. SPR-MBRs achieved effective sludge reduction by enriching hydrolytic (Trichococcus and Aeromonas) and fermentative genera (Lactococcus, Paludibacter, Macellibacteroides, and Acinetobacter) in the SPR, and alleviated membrane fouling by prohibiting the growth of extracellular polymeric substance-secreting bacteria and enriching filamentous bacteria to enlarge particle size. The results revealed that the SPR-MBR maximized sludge reduction with a very long sludge retention time, and alleviated membrane fouling synchronously.
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Affiliation(s)
- Yi Zuo
- Shanghai Engineering Research Center of Energy - Saving in Heat Exchange Systems, College of Environmental and Chemical Engineering, Shanghai University of Electric Power, Shanghai, 200090, China
| | - Yanjun Shao
- Shanghai Engineering Research Center of Energy - Saving in Heat Exchange Systems, College of Environmental and Chemical Engineering, Shanghai University of Electric Power, Shanghai, 200090, China
| | - Lihua Wang
- Shanghai Chengtou Wastewater Treatment Co., Ltd, Shanghai, 201203, China
| | - Yiyue Sun
- Shanghai Engineering Research Center of Energy - Saving in Heat Exchange Systems, College of Environmental and Chemical Engineering, Shanghai University of Electric Power, Shanghai, 200090, China
| | - Ying An
- Shanghai Engineering Research Center of Energy - Saving in Heat Exchange Systems, College of Environmental and Chemical Engineering, Shanghai University of Electric Power, Shanghai, 200090, China
| | - Lu-Man Jiang
- Shanghai Engineering Research Center of Energy - Saving in Heat Exchange Systems, College of Environmental and Chemical Engineering, Shanghai University of Electric Power, Shanghai, 200090, China
| | - Nan Yu
- Jinluo Water Co., Ltd, Linyi, 276600, China
| | - Rujie Hao
- Jinluo Water Co., Ltd, Linyi, 276600, China
| | - Chuanting Zhou
- Shanghai Urban Construction Design and Research Institute, Shanghai, 200125, China
| | - Jun Tao
- Shanghai Chengtou Wastewater Treatment Co., Ltd, Shanghai, 201203, China
| | - Zhen Zhou
- Shanghai Engineering Research Center of Energy - Saving in Heat Exchange Systems, College of Environmental and Chemical Engineering, Shanghai University of Electric Power, Shanghai, 200090, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China.
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12
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Wei P, Li J, Zhang J, Zhang Y, Luo R, Xie C, Wang Z. Bioaugmentation with an aerobic denitrifying bacterium with quorum quenching activity for improved nitrogen removal and reduced membrane fouling in anoxic/oxic membrane bioreactor. RSC Adv 2023; 13:2345-2354. [PMID: 36741184 PMCID: PMC9841441 DOI: 10.1039/d2ra06676a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2022] [Accepted: 12/26/2022] [Indexed: 01/17/2023] Open
Abstract
In this study, an aerobic denitrifying bacterium with quorum quenching activity, Acinetobacter sp. WZL728, was inoculated into the anoxic/oxic membrane bioreactor (A/O-MBR) to study its effects on A/O-MBR performance. The pollutant removal and membrane fouling between A/O-MBR with WZL728 (EMBR) and A/O-MBR without WZL728 (CMBR) were compared. WZL728 increased the total nitrogen removal efficiency from 75.05% in CMBR to 91.03% in EMBR and extended the filtration cycle from 5.44 days in CMBR to 9.57 days in EMBR, which indicated that WZL728 improved the pollutant removal performance and mitigated membrane fouling of A/O-MBR. The concentration of N-acyl-homoserine lactones in the biocake of EMBR (EMBRB) was 11.23% of that in the biocake of CMBR (CMBRB). The content of extracellular polymeric substances (EPS) in EMBRB was 69.00% of that in CMBRB. The abundance of bacteria associated with EPS secretion (Alpthaproteobacteria) decreased and the abundance of bacteria associated with EPS degradation (Clostridia) increased in EMBRB. Valine, alanine and uridine diphosphate-N-acetylgalactosamine associated with protein and polysaccharide synthesis were significantly lower in EMBRB than those in CMBRB, which revealed the reason for the decrease of protein and polysaccharide content of EPS within EMBRB. This study provides useful information for improving A/O-MBR performance by probiotics.
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Affiliation(s)
- Pengyuan Wei
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Engineering Research Center of Beijing, Beijing University of TechnologyBeijing 100124PR China
| | - Jun Li
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Engineering Research Center of Beijing, Beijing University of TechnologyBeijing 100124PR China
| | - Jing Zhang
- Beijing City Drainage Refco Group LtdBeijing 100124PR China
| | - Yi Zhang
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Engineering Research Center of Beijing, Beijing University of TechnologyBeijing 100124PR China
| | - Rong Luo
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Engineering Research Center of Beijing, Beijing University of TechnologyBeijing 100124PR China
| | - Chaofan Xie
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Engineering Research Center of Beijing, Beijing University of TechnologyBeijing 100124PR China
| | - Zhaozhao Wang
- The College of Energy and Environmental Engineering, Hebei University of EngineeringHandan 056038PR China
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13
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Park H, Shah SSA, Korshin G, Angelidaki I, Choo KH. The impact of sunlight on fouling behaviors and microbial communities in membrane bioreactors. J Memb Sci 2023. [DOI: 10.1016/j.memsci.2023.121443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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14
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Liang Z, Han H, Yi J, Dai X. Modified integrated fixed-film activated sludge process: Advanced nitrogen removal for low-C/N domestic wastewater. CHEMOSPHERE 2022; 307:135827. [PMID: 35944692 DOI: 10.1016/j.chemosphere.2022.135827] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 06/26/2022] [Accepted: 07/22/2022] [Indexed: 06/15/2023]
Abstract
Actual low-C/N domestic wastewater was treated using the high-concentration powder carrier bio-fluidized bed (HPB) process comparing diatomite and Fe-C as the carriers. The total nitrogen removal efficiencies were increased from 50.08% to 65.40% and 78.58%, respectively. The diatomite HPB process increased the relative abundance of autotrophic N-cycle bacteria to more than twofold and the sludge size. Therefore, the contributions for nitrogen removal by anammox and simultaneous nitrification-denitrification were increased. The Fe-C HPB process improved the nitrogen removal efficiency mainly by increasing the biodegradability and activities of electron transfer system and key enzymes. The key device (hydrocyclone separator) of the HPB process significantly improved the recovery efficiency of the carriers. It also improved the capacity of microbial aggregations for adsorbing pollutants. Furthermore, it reduced the relative abundance of filamentous bacteria. This study demonstrated the feasibility and mechanism of the HPB process for improving the nitrogen removal efficiency for low-C/N wastewater.
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Affiliation(s)
- Zixuan Liang
- Tongji University, College of Environmental Science and Engineering, State Key Lab Pollution Control and Resource Reuse, Shanghai, 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China
| | - Hongbo Han
- Hunan Sanyou Environmental Protection Co. Ltd., Changsha, Hunan, China
| | - Jing Yi
- Hunan Sanyou Environmental Protection Co. Ltd., Changsha, Hunan, China
| | - Xiaohu Dai
- Tongji University, College of Environmental Science and Engineering, State Key Lab Pollution Control and Resource Reuse, Shanghai, 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China.
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15
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Song T, Zhang X, Li J. Aerobic granular sludge with filamentous bacteria immobilized by string carriers to treat simulated municipal wastewater in a continuous flow reactor. BIORESOURCE TECHNOLOGY 2022; 363:127917. [PMID: 36089129 DOI: 10.1016/j.biortech.2022.127917] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 08/30/2022] [Accepted: 09/04/2022] [Indexed: 06/15/2023]
Abstract
Aerobic granular sludge with filamentous bacteria (FAGS) has displayed many desirable properties. However, the selective pressure based on settling speed cannot effectively separate FAGS from water in sequencing batch reactor (SBR), which limits FAGS development. In this study, a new selection pressure was created by adding string carriers. Strings were used as crystal nuclei to form immobilized FAGS to achieve rapid separation from water. The immobilization of FAGS was achieved in both SBR and continuous flow reactor (CFR). The immobilization and long-term operation of FAGS in CFR were explored. NH4+ and COD removal efficiency remained above 90 % and 85 %, respectively. Sphaerotilus, denitrifying microorganisms and EPS-secreting microorganisms were the main microorganisms in the immobilized FAGS. The selection pressure provided by the strings, the operating characteristics of the CFR, and the properties of Sphaerotilus may play key role in the immobilization of FAGS.
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Affiliation(s)
- Tao Song
- School of Civil and Environmental Engineering, Shenzhen Key Laboratory of Water Resource Application and Environmental Pollution Control, Harbin Institute of Technology, Shenzhen, Shenzhen, Guangdong 518055, PR China
| | - Xiaolei Zhang
- School of Civil and Environmental Engineering, Shenzhen Key Laboratory of Water Resource Application and Environmental Pollution Control, Harbin Institute of Technology, Shenzhen, Shenzhen, Guangdong 518055, PR China
| | - Ji Li
- School of Civil and Environmental Engineering, Shenzhen Key Laboratory of Water Resource Application and Environmental Pollution Control, Harbin Institute of Technology, Shenzhen, Shenzhen, Guangdong 518055, PR China; Shenzhen Key Laboratory of Water Resource Utilization and Environmental Pollution Control, Shenzhen 518055, PR China; State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, PR China.
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16
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Significance of Ferric Chloride Addition on the Treatment Performance of Cloth-Media MBR Treating Municipal Wastewater. ARABIAN JOURNAL FOR SCIENCE AND ENGINEERING 2022. [DOI: 10.1007/s13369-022-07373-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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17
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He J, Zhang Q, Tan B, Guo N, Peng H, Feng J, Su J, Zhang Y. Understanding the effect of residual aluminum salt coagulant on activated sludge in sequencing batch reactor: Performance response, activity restoration and microbial community evolution. ENVIRONMENTAL RESEARCH 2022; 212:113449. [PMID: 35561832 DOI: 10.1016/j.envres.2022.113449] [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: 02/02/2022] [Revised: 04/07/2022] [Accepted: 05/05/2022] [Indexed: 06/15/2023]
Abstract
To investigate the effect of residual coagulant after coagulation pretreatment on activated sludge system of wastewater treatment plants (WWTPs), comparative evaluation of lab-scale sequencing batch reactors under different poly-aluminum chloride (PAC) concentrations (20 and 55 mg/L), presenting the performance differences of reactors. Results showed that the PAC concentration of 20 mg/L slightly enhanced the average removal efficiencies of chemical oxygen demand (COD) and total nitrogen (TN), up to 93.43% and 72.52%. Whereas, an inhibition effect was exerted at the PAC concentration of 55 mg/L, the average removal efficiencies decreased to 88.56% and 57.80% respectively. Similarly, the residual aluminum salts showed a concentration effect of low promotion and high inhibition on sludge activity index. The content of specific oxygen utilization rate (SOUR) and dehydrogenase (DHA) sharply decreased by 30.17% and 53.56% under the high PAC concentration of 55 mg/L. Activity recovery phase showed that the suppression of aluminum salt coagulant on biological system was reversible. High-throughput sequencing presented that the relative abundance of microbes showed obvious variations at different PAC concentrations, and certain bacteria in Chloroflexi and Bacteroidota exhibited better adaptability to the high PAC concentration environment. Nevertheless, the antagonism action between denitrifying genera and other genera as well as the downregulation of functional enzymes regarding nitrogen metabolism gave rise to the deterioration of denitrification under the high PAC concentration of 55 mg/L. This study revealed the influence mechanism of residual aluminum salt coagulant on activated sludge system, providing strategies for efficient decontamination and long-term stable operation of biological system in wastewater treatment plant under the condition of adding PAC.
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Affiliation(s)
- Jing He
- School of Civil Engineering & Architecture, Wuhan University of Technology, Wuhan, 430070, PR China
| | - Qian Zhang
- School of Civil Engineering & Architecture, Wuhan University of Technology, Wuhan, 430070, PR China.
| | - Bin Tan
- Wuhan Branch, Chengdu JiZhun FangZhong Architectural Design, Wuhan, 40061, PR China
| | - Nuowei Guo
- School of Civil Engineering & Architecture, Wuhan University of Technology, Wuhan, 430070, PR China
| | - Haojin Peng
- School of Civil Engineering & Architecture, Wuhan University of Technology, Wuhan, 430070, PR China
| | - Jiapeng Feng
- School of Civil Engineering & Architecture, Wuhan University of Technology, Wuhan, 430070, PR China
| | - Junhao Su
- School of Civil Engineering & Architecture, Wuhan University of Technology, Wuhan, 430070, PR China
| | - Yunjie Zhang
- School of Civil Engineering & Architecture, Wuhan University of Technology, Wuhan, 430070, PR China
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18
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Wang C, Lin Q, Yao Y, Xu R, Wu X, Meng F. Achieving simultaneous nitrification, denitrification, and phosphorus removal in pilot-scale flow-through biofilm reactor with low dissolved oxygen concentrations: Performance and mechanisms. BIORESOURCE TECHNOLOGY 2022; 358:127373. [PMID: 35623607 DOI: 10.1016/j.biortech.2022.127373] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 05/18/2022] [Accepted: 05/21/2022] [Indexed: 06/15/2023]
Abstract
In this pilot-scale study, a flow-through biofilm reactor (FTBR) was investigated for municipal wastewater treatment. The removal efficiencies for ammonium, total nitrogen, total phosphorus, and chemical oxygen demand were 87.2 ± 17.9%, 61.1 ± 13.9%, 83.5 ± 11.9%, and 92.6 ± 1.7%, respectively, at low dissolved oxygen concentrations (averaged at 0.59 mg/L), indicating the feasibility and robustness of the FTBR for a simultaneous nitrification, denitrification, and phosphorous removal (SNDPR) process. The co-occurrence network of bacteria in the dynamic biofilm was complex, with equivalent bacterial cooperation and competition. Nevertheless, the bacterial interactions in the suspended sludge were mainly cooperative. The presence of dynamic biofilms increased bacterial diversity by creating niche differentiation, which enriched keystone species closely related to nutrient removal. Overall, this study provides a novel FTBR-based SNDPR process and reveals the ecological mechanisms responsible for nutrient removal.
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Affiliation(s)
- Chao Wang
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510006, PR China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Guangzhou 510006, PR China
| | - Qining Lin
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510006, PR China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Guangzhou 510006, PR China
| | - Yuanyuan Yao
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510006, PR China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Guangzhou 510006, PR China
| | - Ronghua Xu
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510006, PR China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Guangzhou 510006, PR China
| | - Xueshen Wu
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510006, PR China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Guangzhou 510006, PR China
| | - Fangang Meng
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510006, PR China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Guangzhou 510006, PR China.
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19
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Li C, Maqbool T, Kang H, Zhang Z. In-Situ Sludge Reduction in Membrane-Controlled Anoxic-Oxic-Anoxic Bioreactor: Performance and Mechanism. MEMBRANES 2022; 12:membranes12070659. [PMID: 35877863 PMCID: PMC9321052 DOI: 10.3390/membranes12070659] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 06/20/2022] [Accepted: 06/23/2022] [Indexed: 01/27/2023]
Abstract
Conventional and advanced biological wastewater treatment systems generate excess sludge, which causes socio-economic and environmental issues. This study investigated the performance of membrane-controlled anoxic-oxic-anoxic (AOA) bioreactors for in-situ sludge reduction compared to the conventional anoxic-oxic-oxic membrane bioreactor (MBRcontrol). The membrane units in the AOA bioreactors were operated as anoxic reactors at lower sludge recirculation rates to achieve hydrolysis of extracellular polymeric substances (EPS) and extensive endogenous respiration. Compared to MBRcontrol, the AOA bioreactors operated with 90%, and 80% recirculation rates reduced the sludge growth up to 19% and 30%, respectively. Protein-like components were enriched in AOA bioreactors while fulvic-like components were dominant in MBRcontrol. The growth of Dechloromonas and Zoogloea genra was promoted in AOA bioreactors and thus sludge reduction was facilitated. Metagenomics analysis uncovered that AOA bioreactors exhibited higher proportions of key genes encoding enzymes involved in the glycolysis and denitrification processes, which contributed to the utilization of carbon sources and nitrogen consumption and thus sludge reduction.
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Affiliation(s)
- Chengyue Li
- Institute of Environmental Engineering & Nano-Technology, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China; (C.L.); (T.M.); (H.K.)
- Guangdong Provincial Engineering Research Centre for Urban Water Recycling and Environmental Safety, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
- School of Environment, Tsinghua University, Beijing 100084, China
| | - Tahir Maqbool
- Institute of Environmental Engineering & Nano-Technology, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China; (C.L.); (T.M.); (H.K.)
- Guangdong Provincial Engineering Research Centre for Urban Water Recycling and Environmental Safety, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
- School of Environment, Tsinghua University, Beijing 100084, China
| | - Hongyu Kang
- Institute of Environmental Engineering & Nano-Technology, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China; (C.L.); (T.M.); (H.K.)
- Guangdong Provincial Engineering Research Centre for Urban Water Recycling and Environmental Safety, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
- School of Environment, Tsinghua University, Beijing 100084, China
| | - Zhenghua Zhang
- Institute of Environmental Engineering & Nano-Technology, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China; (C.L.); (T.M.); (H.K.)
- Guangdong Provincial Engineering Research Centre for Urban Water Recycling and Environmental Safety, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
- School of Environment, Tsinghua University, Beijing 100084, China
- Correspondence:
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20
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Liu Y, Lin Q, Guo Y, Zhao J, Luo X, Zhang H, Li G, Liang H. The nitrogen-doped multi-walled carbon nanotubes modified membrane activated peroxymonosulfate for enhanced degradation of organics and membrane fouling mitigation in natural waters treatment. WATER RESEARCH 2022; 209:117960. [PMID: 34923440 DOI: 10.1016/j.watres.2021.117960] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 12/07/2021] [Accepted: 12/09/2021] [Indexed: 06/14/2023]
Abstract
The synthesized catalyst nitrogen-doped multi-walled carbon nanotubes (N-MWCNTs) were introduced into membrane technology for peroxymonosulfate (PMS) activation. The enhanced permeability of the N-MWCNTs-modified membrane might be attributed to the increase in hydrophilicity and membrane porosity. The catalytic degradation and membrane filtration performance for the N-MWCNTs-modified membrane/PMS system in treating different types of natural waters were evaluated. The removal of phenol by the N-MWCNTs-modified membrane was 83.67% in 2 min, which was greater than the phenol removal by the virgin membrane (3.39%) and N-MWCNT powder (41.42%), respectively. Moreover, the resultant membrane coupled with PMS activation exhibited outstanding removal effects on the fluorescent organics in the secondary effluent and Songhua River water. The combination effectively reduced the total membrane fouling caused by the secondary effluent, Songhua River water, and three typical model organics by 28.19-61.98%. Electron paramagnetic resonance and classical quenching tests presented that the active species (SO4·-, ·OH, and 1O2) and other non-radical processes generated by N-MWCNTs activated PMS decreased the foulants deposition on the membrane surface. Meanwhile, the membrane interception accelerated the aggregation of pollutants and PMS towards the membrane surface through applied pressure, facilitating their mass transfer to the N-MWCNTs surface for the catalysis exerted more effectively. This study demonstrated the potential application of the coupling of N-MWCNTs catalytic oxidation and the UF, which offers a promising prospect to improve the permeate quality and simultaneously overcome the membrane fouling barriers.
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Affiliation(s)
- Yatao Liu
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Quan Lin
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Yuanqing Guo
- School of Civil Engineering, Chang'an University, Xi'an 710061, China
| | - Jing Zhao
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Xinsheng Luo
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Han Zhang
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Guibai Li
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Heng Liang
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China.
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21
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Du P, Li X, Yang Y, Zhou Z, Fan X, Chang H, Liang H. Regulated-biofilms enhance the permeate flux and quality of gravity-driven membrane (GDM) by in situ coagulation combined with activated alumina filtration. WATER RESEARCH 2022; 209:117947. [PMID: 34910991 DOI: 10.1016/j.watres.2021.117947] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 12/01/2021] [Accepted: 12/06/2021] [Indexed: 06/14/2023]
Abstract
It is a critical challenge for drinking water production when treating algae-contaminated surface water. In this study, the impact of in situ coagulation (C), activated alumina filtration (AA) and their combination (CAA) on the performance of gravity-driven membrane (GDM) was systematically assessed during 105-day operation. The results indicated that pretreatments in particular CAA could effectively enhance GDM flux, and the stable fluxes were increased to 3.1, 4.9 and 8.3 L/(m2·h) (LMH) for CGDM, AA/GDM and CAA/GDM, respectively when compared to the control GDM (2.0 LMH). Coagulation was beneficial to formation of thick but loose biofouling layer, while AA filtration was effective to retain foulants including extracellular polymeric substances (EPS), organics, total nitrogen and total phosphorus. The CAA/GDM could mostly remove these foulants, and facilitate the proliferation of bacterial genera that could consume EPS, further alleviating membrane fouling. The difference in loosely bound EPS and tightly bound EPS of biofouling layer attributed to the difference of reversible fouling and irreversible fouling, respectively. Morphological observations, variation in functional groups or elements further confirmed the difference in biological layers in different GDM systems. The occurrence of specific bacterial genera involving the potential to degrade protein, chitin and other high molecular weight organics was responsible for contaminant removals.
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Affiliation(s)
- Peng Du
- College of Architecture and Civil Engineering, Faculty of Urban Construction, Beijing University of Technology, Beijing 100124, China; China Academy of Building Research, Institute of Building Fire Research, Beijing 100013, China
| | - Xing Li
- College of Architecture and Civil Engineering, Faculty of Urban Construction, Beijing University of Technology, Beijing 100124, China
| | - Yanling Yang
- College of Architecture and Civil Engineering, Faculty of Urban Construction, Beijing University of Technology, Beijing 100124, China
| | - Zhiwei Zhou
- College of Architecture and Civil Engineering, Faculty of Urban Construction, Beijing University of Technology, Beijing 100124, China.
| | - Xiaoyan Fan
- College of Architecture and Civil Engineering, Faculty of Urban Construction, Beijing University of Technology, Beijing 100124, China
| | - Haiqing Chang
- MOE Key Laboratory of Deep Earth Science and Engineering, College of Architecture and Environment, Sichuan University, Chengdu 610207, China.
| | - Heng Liang
- State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), Harbin Institute of Technology, Harbin 150090, China
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22
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Shao Y, Zhou Z, Jiang J, Jiang LM, Huang J, Zuo Y, Ren Y, Zhao X. Membrane fouling in anoxic/oxic membrane reactors coupled with carrier-enhanced anaerobic side-stream reactor: Effects of anaerobic hydraulic retention time and mechanism insights. J Memb Sci 2021. [DOI: 10.1016/j.memsci.2021.119657] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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23
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Zhou L, Ou P, Zhao B, Zhang W, Yu K, Xie K, Zhuang WQ. Assimilatory and dissimilatory sulfate reduction in the bacterial diversity of biofoulant from a full-scale biofilm-membrane bioreactor for textile wastewater treatment. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 772:145464. [PMID: 33571768 DOI: 10.1016/j.scitotenv.2021.145464] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 01/23/2021] [Accepted: 01/24/2021] [Indexed: 06/12/2023]
Abstract
Assimilatory and dissimilatory sulfate reduction (ASR and DSR) are the core bacterial sulfate-reducing pathways involved in wastewater treatment. It has been reported that sulfate-reducing activities could happen within biofoulants of membrane bioreactors during wastewater treatment. Biofoulants are mainly microbial products contributing membrane fouling and subsequent rising energy consumption in driving membrane filtration. Biofoulants from a full-scale biofilm-membrane bioreactor (biofilm-MBR) treating textile wastewater were investigated in this study. During a 10-month operation, sulfate concentrations in the effluent of the biofilm-MBR gradually decreased alongside with the creeping up sulfite concentrations when biofoulants were also building up on membrane modules. Sulfide had no apparent increases in the effluent during this period. Metagenomic analysis revealed diverse microbial communities residing in the biofoulants. Further analysis on their genetic traits revealed abundant ASR's and DSR's functional genes. A plethora of sulfate-reduction bacteria (SRB), including the well-known Desulfovibrio, Desulfainum, Desulfobacca, Desulfobulbus, Desulfococcus, Desulfonema, Desulfosarcina, Desulfobacter, Desulfobacula, Desulfofaba, Desulfotigum, Desulfatibacillum, Desulfatitalea, Desulfobacterium, were detected in the biofoulants. They were believed to play some important carbon and sulfur-cycling roles in our study. Based on metagenomic analysis, we also deduced that ASR was a functionally more important sulfate-reducing route because of the high abundance of assimilatory sulfate reductases detected. Also, the "AMP (adenosine monophosphate)→sulfite" step was a key reaction shared by both ASR and DSR in the biofoulant. This step might be responsible for the sulfite accumulation in the biofilm-MBR effluent. Overall, ASR functional genes in the biofoulants were more abundant. But the bacteria possessing complete DSR pathways caused the sulfide production in the biofilm-MBR.
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Affiliation(s)
- Lijie Zhou
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, China.
| | - Pingxiang Ou
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, China
| | - Bikai Zhao
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, China
| | - Wenyu Zhang
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, China
| | - Ke Yu
- School of Environment and Energy, Peking University Shenzhen Graduate School, Guangdong, Shenzhen 518055, China
| | - Kang Xie
- School of Civil Engineering and Architecture, University of Jinan, Jinan 250022, China
| | - Wei-Qin Zhuang
- Department of Civil and Environmental Engineering, University of Auckland, Auckland 1142, New Zealand
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24
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Cui Y, Gao H, Yu R, Gao L, Zhan M. Biological-based control strategies for MBR membrane biofouling: a review. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2021; 83:2597-2614. [PMID: 34115616 DOI: 10.2166/wst.2021.168] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Membrane bioreactor (MBR) technology has been paid extensive attention for wastewater treatment because of its advantages of high effluent quality and minimized occupation space and sludge production. However, the membrane fouling is always an inevitable problem, which causes high operation and maintenance costs and prevents the wide use of MBR technology. The membrane biofouling is the most complicated and has relatively slow progress among all types of fouling. In recent years, many membrane biofouling control methods have been developed. Different from the physical or chemical methods, the biological-based strategies are not only more effective for membrane biofouling control, but also milder and more environment-friendly and, therefore, have been increasingly employed. This paper mainly focuses on the mechanism, unique advantages and development of biological-based control strategies for MBR membrane biofouling such as quorum quenching, uncoupling, flocculants and so on. The paper summarizes the up-to-date development of membrane biofouling control strategies, emphasizes the advantages and promising potential of biological-based ones, and points out the direction for future studies.
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Affiliation(s)
- Yin Cui
- Department of Environmental Science and Engineering, School of Energy and Environment, Wuxi Engineering Research Center of Taihu Lake Water Environment, Southeast University, Nanjing, Jiangsu 210096, China and Key Laboratory of Environmental Medicine Engineering, Ministry of Education, Southeast University, Nanjing, Jiangsu 210009, China E-mail:
| | - Huan Gao
- Department of Environmental Science and Engineering, School of Energy and Environment, Wuxi Engineering Research Center of Taihu Lake Water Environment, Southeast University, Nanjing, Jiangsu 210096, China and Key Laboratory of Environmental Medicine Engineering, Ministry of Education, Southeast University, Nanjing, Jiangsu 210009, China E-mail:
| | - Ran Yu
- Department of Environmental Science and Engineering, School of Energy and Environment, Wuxi Engineering Research Center of Taihu Lake Water Environment, Southeast University, Nanjing, Jiangsu 210096, China and Key Laboratory of Environmental Medicine Engineering, Ministry of Education, Southeast University, Nanjing, Jiangsu 210009, China E-mail:
| | - Lei Gao
- Department of Environmental Science and Engineering, School of Energy and Environment, Wuxi Engineering Research Center of Taihu Lake Water Environment, Southeast University, Nanjing, Jiangsu 210096, China and Key Laboratory of Environmental Medicine Engineering, Ministry of Education, Southeast University, Nanjing, Jiangsu 210009, China E-mail:
| | - Manjun Zhan
- Nanjing Research Institute of Environmental Protection, Nanjing Environmental Protection Bureau, Nanjing, Jiangsu 210013, China
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25
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He JY, Zhang HL, Wang H, Hu YQ, Zhang Y. Characteristics of the extracellular products of pure oxygen aerated activated sludge in batch mode. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2021; 83:1946-1957. [PMID: 33905364 DOI: 10.2166/wst.2021.099] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The effects of pure oxygen aeration on compositional characteristics of soluble microbial products (SMP) and extracellular polymeric substances (EPS) of the activated sludge acclimated in a sequential batch reactor (SBR) were explored in batch mode. The structure of the extracellular products would change with different aeration methods or aeration rates. The proportion of SMP of most oxygen aerated sludge was less than 10%, while that in air aerated sludge was as high as 30-40%. The proportion of TB-EPS decreased from 56.95% to 30.63%, and the proportion of LB-EPS increased obviously with the increase of oxygen aeration rate. The contents of the protein (PN) and the polysaccharide (PS) of extracellular products with oxygen aeration were significantly different, and the PN was much higher than PS (p < 0.05). The zeta potential of each component in activated sludge was negative, gradually decreasing with the progress of biological treatment. The fluorescence peaks in SMP, LB-EPS and TB-EPS with pure oxygen aeration were attributed to tryptophan PN-like and humic acid-like fractions. The results showed that the proportion of the components in the extracellular products could be regulated by adjusting the aeration rate and aeration mode, so as to optimize the treatment process of activated sludge.
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Affiliation(s)
- Jia-Ying He
- School of the Environment, Nanjing Normal University, Nanjing 210023, China E-mail: ; † These two authors contributed equally to this paper
| | - Hong-Ling Zhang
- Nanjing Institute of Environmental Science, MEP, Nanjing 210000, China; † These two authors contributed equally to this paper
| | - Hong Wang
- School of the Environment, Nanjing Normal University, Nanjing 210023, China E-mail:
| | - Ya-Qi Hu
- School of the Environment, Nanjing Normal University, Nanjing 210023, China E-mail:
| | - Yong Zhang
- School of the Environment, Nanjing Normal University, Nanjing 210023, China E-mail: ; Key Laboratory of Virtual Geographic Environment (Nanjing Normal University), Ministry of Education, Nanjing 210023, China; State Key Laboratory Cultivation Base of Geographical Environment Evolution (Jiangsu Province), Nanjing 210023, China and Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing 210023, China
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26
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Gong TT, He XH, Gao S, Wu QJ. Application of machine learning in prediction of Chemotherapy resistant of Ovarian Cancer based on Gut Microbiota. J Cancer 2021; 12:2877-2885. [PMID: 33854588 PMCID: PMC8040891 DOI: 10.7150/jca.46621] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 03/03/2021] [Indexed: 01/04/2023] Open
Abstract
Background: Ovarian cancer (OC) has the highest mortality among gynecological malignancies, and resistance to chemotherapy drugs is common. We aim to develop a machine learning approach based on gut microbiota to predict the chemotherapy resistance of OC. Methods: The study included patients diagnosed with OC by pathology and treated with platinum and paclitaxel in Shengjing Hospital of China Medical University between 2017 and 2018. Fecal samples were collected from patients, and 16S rRNA sequencing was used to analyze the differences in gut microbiota between OC patients with and without chemotherapy resistance. Nine machine learning classifiers were used to derive the chemotherapy resistance of OC from gut microbiota. Results: A total of 77 chemoresistant OC patients and 97 chemosensitive OC patients were enrolled. The gut microbiota diversity was higher in OC patients with chemotherapy resistance. There were statistically significant differences between the two groups in Shannon indexes (P <0.05) and Simpson indexes (P <0.05). Machine learning techniques can predict the chemoresistance of OC, and the random forest showed the best performance among all models. The area under the ROC curve for RF model was 0.909. Conclusions: The diversity of gut microbiota was higher in OC patients with chemotherapy resistance. Further studies are warranted to validate our findings based on machine learning techniques.
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Affiliation(s)
- Ting-Ting Gong
- Department of Obstetrics and Gynecology, Shengjing Hospital of China Medical University, Shenyang, China
| | - Xin-Hui He
- Department of Clinical Epidemiology, Shengjing Hospital of China Medical University, Shenyang, China
| | - Song Gao
- Department of Clinical Epidemiology, Shengjing Hospital of China Medical University, Shenyang, China
| | - Qi-Jun Wu
- Department of Obstetrics and Gynecology, Shengjing Hospital of China Medical University, Shenyang, China
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27
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Zhu Z, Shan L, Zhang X, Hu F, Zhong D, Yuan Y, Zhang J. Effects of bacterial community composition and structure in drinking water distribution systems on biofilm formation and chlorine resistance. CHEMOSPHERE 2021; 264:128410. [PMID: 33002803 DOI: 10.1016/j.chemosphere.2020.128410] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 08/25/2020] [Accepted: 09/19/2020] [Indexed: 06/11/2023]
Abstract
Community-intrinsic properties affect the composition and function of a microbial community. Understanding the microbial community-intrinsic properties in drinking water distribution systems (DWDS) could help to select disinfection strategies and aid in the prevention of waterborne infectious diseases. In this study, we investigated the formation of multi-species biofilms in six groups, each consisting of four or five mixed bacterial strains isolated from a simulated DWDS, at different incubation times (24, 48, and 72 h). We then evaluated the chlorine resistance of the 72-h multi-species biofilms in the presence of 0.3, 0.6, 1, 2, 4, and 10 mg/L residual chlorine. Microbacterium laevaniformans inhibited the formation of multi-species biofilms, Sphingomonas sp., Acinetobacter sp. and A. deluvii had the effect of promoting their growth, and B. cereus has little effect on the growth of multi-species biofilms. However, these inhibition and promotion effects were weak and inadequate to completely control the growth of multi-species biofilms. All multi-species produced strong biofilms after 72 h incubation, which could be due to microbial community-intrinsic properties. Community-intrinsic properties could maintain high EPS production and cell-to-cell connections in multi-species biofilms, and could affect the formation of multi-species biofilms. The chlorine resistance of multi-species biofilms was significantly improved by B. cereus, but significantly reduced by M. laevaniformans. These results indicated that the microbial community-intrinsic properties were influenced by the environment. At a relatively low disinfectant concentration (<2 mg/L residual chlorine), the community-intrinsic properties were maintained; however, when the disinfectant concentration was increased to 2-4 mg/L residual chlorine, the community-intrinsic properties weakened, and significantly affected the resistance of the microbial communities to the disinfectant. With further increases in concentration, to >4 mg/L residual chlorine, no significant difference was observed in the disinfectant resistance of the microbial community.
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Affiliation(s)
- Zebing Zhu
- School of Civil Engineering and Architecture, East China Jiao Tong University, Nanchang, 330013, PR China; State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, PR China.
| | - Lili Shan
- School of Civil Engineering and Architecture, East China Jiao Tong University, Nanchang, 330013, PR China
| | - Xinyun Zhang
- School of Civil Engineering and Architecture, East China Jiao Tong University, Nanchang, 330013, PR China
| | - Fengping Hu
- School of Civil Engineering and Architecture, East China Jiao Tong University, Nanchang, 330013, PR China.
| | - Dan Zhong
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, PR China
| | - Yixing Yuan
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, PR China
| | - Jie Zhang
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, PR China
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