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Zhang R, Hao L, Cheng K, Xin B, Sun J, Guo J. Research progress of electrically-enhanced membrane bioreactor (EMBR) in pollutants removal and membrane fouling alleviation. CHEMOSPHERE 2023; 331:138791. [PMID: 37105306 DOI: 10.1016/j.chemosphere.2023.138791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Revised: 04/11/2023] [Accepted: 04/24/2023] [Indexed: 05/19/2023]
Abstract
Membrane bioreactor (MBR), as a biological unit for wastewater treatment, has been proven to have the advantages of simple structure and high pollutant removal rate. However, membrane fouling limits its wide application, and it is crucial to adopt effective membrane fouling control methods. As a new type of membrane fouling control technology, electrically-enhanced MBR (EMBR) has attracted more interest recently. It uses the driving force of electric field to make pollutants flocculate or move away from the membrane surface to achieve the purpose of inhibiting membrane fouling. This paper expounds the configuration of EMBR in recent years, including the location of membrane components, the way of electric field application and the selection of electrode and membrane materials, and provides the latest development information in various aspects. The enhanced effect of electric field on the removal of comprehensive and refractory pollutants is outlined in detail. And from the perspective of sludge properties (EPS, SMP, sludge particle size, zeta potential and microbial activity), the influence of electric field on sludge characteristics and the relationship between the changes of sludge properties in EMBR and membrane fouling are discussed. Moreover, the electrochemical mechanisms of electric field alleviating membrane fouling are elucidated from electrophoresis, electrostatic repulsion, electroflocculation, electroosmosis, and electrochemical oxidation, and the regeneration and stability of EMBR are assessed. The existing challenges and future research directions are also proposed. This review could provide theoretical guidance and further studies for subsequent topic, and promoting the wide engineering applications of EMBR.
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Affiliation(s)
- Rong Zhang
- Key Laboratory of Subsurface Hydrology and Ecological Effects in Arid Region, Ministry of Education, School of Water and Environment Chang'an University, Xi'an, 710054, PR China.
| | - Liying Hao
- Key Laboratory of Subsurface Hydrology and Ecological Effects in Arid Region, Ministry of Education, School of Water and Environment Chang'an University, Xi'an, 710054, PR China.
| | - Kai Cheng
- Key Laboratory of Subsurface Hydrology and Ecological Effects in Arid Region, Ministry of Education, School of Water and Environment Chang'an University, Xi'an, 710054, PR China.
| | - Beiyu Xin
- Key Laboratory of Subsurface Hydrology and Ecological Effects in Arid Region, Ministry of Education, School of Water and Environment Chang'an University, Xi'an, 710054, PR China.
| | - Junqi Sun
- Key Laboratory of Subsurface Hydrology and Ecological Effects in Arid Region, Ministry of Education, School of Water and Environment Chang'an University, Xi'an, 710054, PR China.
| | - Jifeng Guo
- Key Laboratory of Subsurface Hydrology and Ecological Effects in Arid Region, Ministry of Education, School of Water and Environment Chang'an University, Xi'an, 710054, PR China.
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2
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A deep neural networks framework for in-situ biofilm thickness detection and hydrodynamics tracing for filtration systems. Sep Purif Technol 2022. [DOI: 10.1016/j.seppur.2022.121959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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3
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Nayeri D, Mousavi SA. A comprehensive review on the coagulant recovery and reuse from drinking water treatment sludge. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2022; 319:115649. [PMID: 35834847 DOI: 10.1016/j.jenvman.2022.115649] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 06/01/2022] [Accepted: 06/27/2022] [Indexed: 06/15/2023]
Abstract
The main treatment unit in conventional systems for surface water is coagulation-flocculation (CF) process, which consumes huge quantities of coagulant, and produces large volume of sludge. The produced sludge is known as one of the components of water treatment sludge (WTS), which is considered as a global issue and hot topic require careful attention from the plant operators and sludge managers to be managed sustainably with applying an ecofriendly method. Among the suggested technologies, recovery and reuse of coagulants from WTS show the potential to decrease the waste disposal and chemicals usage for drinking water treatment significantly. So, this comprehensive review provides a useful insight into environmental and health problems of WTS, reports the sources, physicochemical properties of sludge, describes different sludge management methods by more focus on coagulant recovery (CR), which significantly point out the different aspects of WTS recovery and reuse, and eventually, economic evaluation of the CR process was also discussed. The results of this review confirm that coagulants can be recovered from WTS by different methods and also will be reused for multiple times in the removal of pollutants from water and wastewater. Moreover, the recovered coagulants can be used as building and construction materials, constructed wetlands substrate and other aims.
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Affiliation(s)
- Danial Nayeri
- Department of Environmental Health Engineering, School of Public Health, Kermanshah University of Medical Sciences, Kermanshah, Iran; Student Research Committee, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Seyyed Alireza Mousavi
- Department of Environmental Health Engineering, School of Public Health, Kermanshah University of Medical Sciences, Kermanshah, Iran.
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Ma B, Liu Y, Lin H, Fan H, Lu C, Zhao K, Qi J. A pilot-scale study of the integrated floc-ultrafiltration membrane-based drinking water treatment process. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 830:154809. [PMID: 35341872 DOI: 10.1016/j.scitotenv.2022.154809] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 02/18/2022] [Accepted: 03/21/2022] [Indexed: 06/14/2023]
Abstract
Although applications of the integrated ultrafiltration (UF) membrane have been investigated for years, most studies have been conducted at the lab scale. Here, a case study on the integrated Fe-based floc-UF process was presented. To enhance membrane performance, both pre-filtration (bag filter) and pre-oxidation were used as pretreatments to remove particles and inhibit the development of microorganisms. Results showed that the integrated process operated stably with pre-treatments, and the UF membrane fouling behavior could be divided into three different phases: slow increase rate (phase I), medium increase rate (phase II), and fast increase rate (phase III). In comparison to those in phases II and III, both natural organic matters and colloids were the main membrane fouling mechanisms during phase I, as the pollutants were not successfully removed by flocs initially. With the continuous injection of flocs, a loose cake layer became the main fouling mechanism during phase II, resulting in the deterioration of membrane fouling. During phase III, however, microorganisms (e.g., Proteobacteria) were inevitably nourished within the cake layer and played an important role in aggravating the degree of membrane fouling. During this integrated membrane-based process, several operating factors, including floc concentration, sludge discharge frequency, and the aeration rate during backwashing, played important roles in determining membrane performance. In addition, except for oxygen consumption, all the effluent quality parameters met the drinking water criteria followed in China (GB5749-2006).
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Affiliation(s)
- Baiwen Ma
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; Lehrstuhl für Technische Chemie II, Universität Duisburg-Essen, Essen 45117, Germany.
| | - Yansong Liu
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; College of New Energy and Environment, Jilin University, Changchun, 130021, Jilin, China
| | - Hui Lin
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hongwei Fan
- College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Chaojie Lu
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Kai Zhao
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jing Qi
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
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Chen F, Ma J, Zhu Y, Li X, Yu H, Sun Y. Biodegradation performance and anti-fouling mechanism of an ICME/electro-biocarriers-MBR system in livestock wastewater (antibiotic-containing) treatment. JOURNAL OF HAZARDOUS MATERIALS 2022; 426:128064. [PMID: 34922131 DOI: 10.1016/j.jhazmat.2021.128064] [Citation(s) in RCA: 45] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2021] [Revised: 12/07/2021] [Accepted: 12/08/2021] [Indexed: 06/14/2023]
Abstract
Livestock wastewater is an important reservoir of antibiotic resistance genes (ARGs) and antibiotic residues. Membrane fouling is one of the most challenging problems confining the operation and application of membrane bioreactor (MBR). In this work, a novel iron-carbon micro-electrolysis (ICME)/electro-biocarriers-MBR system was established to explore the performance of pollutant removal and anti-fouling for an actual livestock wastewater. A light-weight porous ceramsite (bulk density 0.98 g/cm3) was used as the MBR biocarriers. The electrons generated from iron corrosion in the ICME tank traveled through external wires to the stainless steel membrane modules of MBR and the protons were transferred from the MBR tank to the ICME tank through a salt bridge, thus producing a spontaneous electric field. Under the optimized conditions, the system exhibited chemical oxygen demand removal of 76.0%, total suspended solids removal of 100%, antibiotic removal of 86.4%, NH4+-N removal of 91.1%, and ARGs reduction of 6-8 orders of magnitude. The quality of the final effluent can reach the national Class I-A discharge criteria. Adding ceramsite could not only effectively improve biodegradation performance but also alleviate membrane fouling through the migration and enrichment of microbial flora to the ceramsite. The self-generated electric field had no significant improvement effect on pollutant removal, but exhibited good anti-membrane fouling behavior which could be ascribed to (i) oxidization of membrane foulants by the electrochemical products (such as H2O2 and •OH radicals), and (ii) electrostatic repulsion of negatively charged foulants and bacterial cells. The bacterial community structure and diversity were studied using high-throughput pyrosequencing, and the results demonstrated the roles of electric field and biocarriers in enrichment of anti-fouling communities and repulsion of biofouling-creating communities.
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Affiliation(s)
- Fu Chen
- School of Public Administration, Hohai University, Nanjing 210098, China; Engineering Research Center of Ministry of Education for Mine Ecological Restoration, China University of Mining and Technology, Xuzhou 221116, China.
| | - Jing Ma
- School of Public Administration, Hohai University, Nanjing 210098, China; Engineering Research Center of Ministry of Education for Mine Ecological Restoration, China University of Mining and Technology, Xuzhou 221116, China
| | - Yanfeng Zhu
- School of Environment Science and Spatial Informatics, China University of Mining and Technology, Xuzhou 221008, Jiangsu, China
| | - Xiaoxiao Li
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Haochen Yu
- School of Public Administration, Hohai University, Nanjing 210098, China; Engineering Research Center of Ministry of Education for Mine Ecological Restoration, China University of Mining and Technology, Xuzhou 221116, China
| | - Yan Sun
- School of Public Administration, Hohai University, Nanjing 210098, China
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Huang Y, Chen Q, Wang Z, Yan H, Chen C, Yan D, Ji X. Abatement technology of endocrine-disrupting chemicals (EDCs) by means of enhanced coagulation and ozonation for wastewater reuse. CHEMOSPHERE 2021; 285:131515. [PMID: 34265705 DOI: 10.1016/j.chemosphere.2021.131515] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 07/06/2021] [Accepted: 07/08/2021] [Indexed: 06/13/2023]
Abstract
In this study, we have investigated the purification efficiency during enhanced coagulation, ozone oxidation and their combined processes for the removal of trace amounts of EDCs in different DOM matrices. The results indicated that the maximum removal efficiency of EDCs occurred at or near pH 7.0 when measured over a pH range of 4.0-10.0. The addition of natural colloids had a two-part influence. While the floc generated by polyaluminium chloride (PAC) significantly increased in size from 198.0 μm to 290.4 μm with a simultaneous improvement in the removal efficiency of EDCs, the floc size generated by polyferric sulfate (PFS) had no worthwhile change except for a slight decrement. The removal efficiency of EDCs and the decrease in spectral parameters including UVA254, UVA280 and humic-like fluorescence during ozonation processes with and without pre-coagulation were investigated. During the ozonation process, efficient elimination of target EDCs are achieved at low O3 doses (O3/dissolved organic carbon (DOC) < 0.2) in different water matrices. The pH-titration differential absorbance spectra technique further demonstrated that the high reactivity of O3 to EDCs is owing to their phenolic moieties. In addition, when mgO3/mgDOC ratio reaches to ~0.40, >90% of estrogenic activity was eliminated. In a nutshell, ozonation with pre-coagulation together leads to considerably higher abatement of EDCs and estradiol (E2) equivalent values (EEQ) at the same ozone dosage than ozonation only process for wastewater treatment.
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Affiliation(s)
- Yu Huang
- State Key Laboratory of Hydrology-Water Resources & Hydraulic Engineering, Nanjing Hydraulic Research Institute, Nanjing, 210098, China; Center for Eco-Environment Research, Nanjing Hydraulic Research Institute, Nanjing, 210098, China
| | - Qiuwen Chen
- State Key Laboratory of Hydrology-Water Resources & Hydraulic Engineering, Nanjing Hydraulic Research Institute, Nanjing, 210098, China; Yangtze Institute for Conservation and Green Development, Nanjing, 210098, China; Center for Eco-Environment Research, Nanjing Hydraulic Research Institute, Nanjing, 210098, China
| | - Zhiyuan Wang
- State Key Laboratory of Hydrology-Water Resources & Hydraulic Engineering, Nanjing Hydraulic Research Institute, Nanjing, 210098, China; Yangtze Institute for Conservation and Green Development, Nanjing, 210098, China; Center for Eco-Environment Research, Nanjing Hydraulic Research Institute, Nanjing, 210098, China.
| | - Hanlu Yan
- State Key Laboratory of Hydrology-Water Resources & Hydraulic Engineering, Nanjing Hydraulic Research Institute, Nanjing, 210098, China; Center for Eco-Environment Research, Nanjing Hydraulic Research Institute, Nanjing, 210098, China
| | - Cheng Chen
- State Key Laboratory of Hydrology-Water Resources & Hydraulic Engineering, Nanjing Hydraulic Research Institute, Nanjing, 210098, China; Center for Eco-Environment Research, Nanjing Hydraulic Research Institute, Nanjing, 210098, China
| | - Dandan Yan
- State Key Laboratory of Hydrology-Water Resources & Hydraulic Engineering, Nanjing Hydraulic Research Institute, Nanjing, 210098, China; Center for Eco-Environment Research, Nanjing Hydraulic Research Institute, Nanjing, 210098, China
| | - Xiaowen Ji
- School of Environment and Sustainability, University of Saskatchewan, Saskatoon, SK, S7N 5B3, Canada
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Yu X, Lin T, Xu H, Tao H, Chen W. Ultrafiltration of up-flow biological activated carbon effluent: Extracellular polymer biofouling mechanism and mitigation using pre-ozonation with H 2O 2 backwashing. WATER RESEARCH 2020; 186:116391. [PMID: 32947101 DOI: 10.1016/j.watres.2020.116391] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 09/01/2020] [Accepted: 09/04/2020] [Indexed: 06/11/2023]
Abstract
Biofouling is a key problem in membrane filtration, and extracellular polymer substances (EPS) play a key role in biofouling. Biofouling contributes to membrane fouling during ultrafiltration of up-flow biological activated carbon filter (UBACF) effluent. EPS are released when pollutants get attached with membrane surface and when pollutants are in solution phase from cell lysis and by cell secretions. In our study of EPS + humic acid (HA) prepared as the effluent pollutants for ultrafiltration, we found that EPS increased the interfacial forces between the pollutants and the membrane, resulting in membrane fouling. In the early stages of filtration, the main contribution of EPS to membrane fouling was to bond with organic colloids, which led to an increase in the pollutant particle size and zeta potential. This increased the short-range Lewis acid-base (AB) forces from -4.89 nN to -12.59 nN and accelerated the formation of a cake layer. In the late stage of filtration, the EPS increased both the AB and London-van der Waals (LW) forces, thus accelerating membrane fouling. In order to mitigate biofouling, we developed a method of pretreating the effluent with 0.4 mg/L ozone prior to ultrafiltration and backwashing with 8 mg/L H2O2 to sterilize bacteria attached to the membrane surface. This method not only changed the characteristics of the EPS, but also inactivated bacteria by disinfection with H2O2, thereby reducing the amount of EPS. The proposed method provided a long-term stable operation guarantee for ultrafiltration of UBACF effluent.
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Affiliation(s)
- Xiaofei Yu
- Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Hohai University, Nanjing 210098, PR China; College of Environment, Hohai University, Nanjing 210098, PR China
| | - Tao Lin
- Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Hohai University, Nanjing 210098, PR China; College of Environment, Hohai University, Nanjing 210098, PR China.
| | - Hang Xu
- Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Hohai University, Nanjing 210098, PR China; College of Environment, Hohai University, Nanjing 210098, PR China
| | - Hui Tao
- Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Hohai University, Nanjing 210098, PR China; College of Environment, Hohai University, Nanjing 210098, PR China
| | - Wei Chen
- Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Hohai University, Nanjing 210098, PR China; College of Environment, Hohai University, Nanjing 210098, PR China
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Jin X, Liu Y, Wang Y, Zhang S, Zhang W, Jin P, Xu L, Shi X, Wang XC, Lv S. Towards a comparison between the hybrid ozonation-coagulation (HOC) process using Al- and Fe-based coagulants: Performance and mechanism. CHEMOSPHERE 2020; 253:126625. [PMID: 32289602 DOI: 10.1016/j.chemosphere.2020.126625] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2019] [Revised: 03/19/2020] [Accepted: 03/25/2020] [Indexed: 06/11/2023]
Abstract
In this study, the removal performance of a hybrid ozonation-coagulation (HOC) process using AlCl36H2O (Al-HOC) and FeCl36H2O (Fe-HOC) as coagulants for the treatment of wastewater treatment plant (WWTP) effluent and ibuprofen (IBP) was investigated. Compared with the conventional coagulation process and pre-ozonation-coagulation process, much better organic matter removal performance can be achieved for both the Al-HOC and Fe-HOC processes. The Fe-HOC process showed an obviously higher dissolved organic carbon (DOC) removal efficiency than that of the Al-HOC process. Surface hydroxyl groups were determined to be the active sites in generating OH in the HOC process, and the hydrolysed Fe species possessed a higher content of surface hydroxyl groups than the hydrolysed Al species according to fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectra (XPS) analyses. In addition, the hydrolysed Fe species contained a higher portion of tetrahedral sites that were more likely to be stronger Lewis acid sites to react with ozone to generate OH. Furthermore, peroxone reactions in the HOC process were other possible way to enhance the OH generation, and higher H2O2 generation was observed in the Fe-HOC process due to higher O2- generation. Therefore, better removal performance of the Fe-HOC process can be obtained due to the increased OH generation in the Fe-HOC process.
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Affiliation(s)
- Xin Jin
- Key Lab of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an, 710055, China
| | - Yuguo Liu
- Key Lab of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an, 710055, China
| | - Yong Wang
- Key Lab of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an, 710055, China
| | - Shaohua Zhang
- Key Lab of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an, 710055, China
| | - Weijie Zhang
- Key Lab of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an, 710055, China
| | - Pengkang Jin
- Key Lab of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an, 710055, China.
| | - Lu Xu
- Key Lab of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an, 710055, China
| | - Xuan Shi
- Key Lab of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an, 710055, China
| | - Xiaochang C Wang
- Key Lab of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an, 710055, China
| | - Shiwen Lv
- Key Lab of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an, 710055, China
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Liu C, Zhu L, Chen L. Effect of salt and metal accumulation on performance of membrane distillation system and microbial community succession in membrane biofilms. WATER RESEARCH 2020; 177:115805. [PMID: 32311577 DOI: 10.1016/j.watres.2020.115805] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2020] [Revised: 04/02/2020] [Accepted: 04/05/2020] [Indexed: 06/11/2023]
Abstract
Membrane distillation (MD) works as a potential technology for the "zero liquid discharge" water treatment owing to its high concentration brine tolerance. The continuous accumulation of salts and metals in the MD system during the "zero liquid discharge" water treatment inevitably posed remarkable impacts on the biofilm formation as well as the MD performance. Hence, the biofouling mechanism of MD was deeply researched in this study with an emphasis on the roles of salt-stress (NaCl) and metal-stress (Zn and Fe) in biofilm development. The membrane flux decline of MD was effectively mitigated by the appearance of NaCl and ZnO, while that was significantly aggravated under the metal-stress of Fe. Considering the serious membrane scaling caused by NaCl crystals, a sharp flux decline was seen for the NaCl group during the later stage of MD operation. Basing on the 16S rDNA and 16S rRNA analysis, heat-stress, salt-stress, and metal-stress all posed certain impacts on the biofouling development in the MD system, and a more remarkable influence was observed for metal-stress. Under the salt-stress from NaCl, a thin biofilm containing high biovolume of dead cells finally formed, in which the bacterial community mainly consisted of halotolerant and thermophile species. Owing to the Zn2+-stress and oxidation-stress mechanisms of ZnO, the bacteria in the MD system were largely dead and live bacterial community in biofilms was dominated by some gram-negative species. Under the metal-stress from Fe, a rather thick biofilm containing higher biovolume of live cells clearly developed, in which the prevailing species could secret large amounts of EPS and accumulate metabolites around cells as biological surfactants, inducing aggravated membrane biofouling and high risk of membrane wetting.
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Affiliation(s)
- Chang Liu
- Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing, 210098, China; College of Environment, Hohai University, Nanjing, 210098, China
| | - Liang Zhu
- Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing, 210098, China; College of Environment, Hohai University, Nanjing, 210098, China.
| | - Lin Chen
- Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing, 210098, China; College of Environment, Hohai University, Nanjing, 210098, China
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Ma B, Wu S, Wang B, Qi Z, Bai Y, Liu H, Qu J, Wu R. Influence of floc dynamic protection layer on alleviating ultrafiltration membrane fouling induced by humic substances. J Environ Sci (China) 2020; 90:10-19. [PMID: 32081307 DOI: 10.1016/j.jes.2019.11.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 11/12/2019] [Accepted: 11/18/2019] [Indexed: 06/10/2023]
Abstract
Cake layer formation is inevitable over time for ultrafiltration (UF) membrane-based drinking water treatment. Although the cake layer is always considered to cause membrane fouling, it can also act as a "dynamic protection layer", as it further adsorbs pollutants and dramatically reduces their chance of getting to the membrane surface. Here, the UF membrane fouling performance was investigated with pre-deposited loose flocs in the presence of humic acid (HA). The results showed that the floc dynamic protection layer played an important role in removing HA. The higher the solution pH, the more negative the floc charge, resulting in lower HA removal efficiency due to the electrostatic repulsion and large pore size of the floc layer. With decreasing solution pH, a positively charged floc dynamic protection layer was formed, and more HA molecules were adsorbed. The potential reasons were ascribed to the smaller floc size, greater positive charge, and higher roughness of the floc layer. However, similar membrane fouling performance was also observed for the negative and positive floc dynamic protection layers due to their strong looseness characteristics. In addition, the molecular weight (MW) distribution of HA also played an important role in UF membrane fouling behavior. For the small MW HA molecules, the chance of forming a loose cake layer was high with a negatively charged floc dynamic protection layer, while for the large MW HA molecules it was high with a positively charged floc dynamic protection layer. As a result, slight UF membrane fouling was induced.
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Affiliation(s)
- Baiwen Ma
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Siqi Wu
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Bodong Wang
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China
| | - Zenglu Qi
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yaohui Bai
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China.
| | - Huijuan Liu
- School of Environment, State Key Joint Laboratory of Environment Simulation and Pollution Control, Tsinghua University, Beijing, 100084, China; Research Center for Water Quality and Ecology, Tsinghua University, Beijing, 100084, China
| | - Jiuhui Qu
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ruijun Wu
- State Key Laboratory of Membrane Materials and Membrane Applications, Tianjin Motimo Membrane Technology Co., Ltd., Tianjin, 300457, China
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11
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Ma B, Xue W, Ding Y, Hu C, Liu H, Qu J. Removal characteristics of microplastics by Fe-based coagulants during drinking water treatment. J Environ Sci (China) 2019; 78:267-275. [PMID: 30665645 DOI: 10.1016/j.jes.2018.10.006] [Citation(s) in RCA: 135] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 10/21/2018] [Accepted: 10/22/2018] [Indexed: 05/06/2023]
Abstract
Microplastics have caused great concern worldwide recently due to their ubiquitous presence within the marine environment. Up to now, most attention has been paid to their sources, distributions, measurement methods, and especially their eco-toxicological effects. With microplastics being increasingly detected in freshwater, it is urgently necessary to evaluate their behaviors during coagulation and ultrafiltration (UF) processes. Herein, the removal behavior of polyethylene (PE), which is easily suspended in water and is the main component of microplastics, was investigated with commonly used Fe-based salts. Results showed that although higher removal efficiency was induced for smaller PE particles, low PE removal efficiency (below 15%) was observed using the traditional coagulation process, and was little influenced by water characteristics. In comparison to solution pH, PAM addition played a more important role in increasing the removal efficiency, especially anionic PAM at high dosage (with efficiency up to 90.9%). The main reason was ascribed to the dense floc formation and high adsorption ability because of the positively charged Fe-based flocs under neutral conditions. For ultrafiltration, although PE particles could be completely rejected, slight membrane fouling was caused owing to their large particle size. The membrane flux decreased after coagulation; however, the membrane fouling was less severe than that induced by flocs alone due to the heterogeneous nature of the cake layer caused by PE, even at high dosages of Fe-based salts. Based on the behavior exhibited during coagulation and ultrafiltration, we believe these findings will have potential application in drinking water treatment.
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Affiliation(s)
- Baiwen Ma
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Wenjing Xue
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; College of Environment and Safety Engineering, Qingdao University of Science and Technology, Qingdao 266042, China
| | - Yanyan Ding
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chengzhi Hu
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Huijuan Liu
- School of Environment, State Key Joint Laboratory of Environment Simulation and Pollution Control, Tsinghua University, Beijing 100084, China; Research Center for Water Quality and Ecology, Tsinghua University, Beijing 100084, China
| | - Jiuhui Qu
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
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Ding Y, Ma B, Liu H, Qu J. Effects of protein properties on ultrafiltration membrane fouling performance in water treatment. J Environ Sci (China) 2019; 77:273-281. [PMID: 30573091 DOI: 10.1016/j.jes.2018.08.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 08/19/2018] [Accepted: 08/20/2018] [Indexed: 05/09/2023]
Abstract
Protein-like substances always induce severe ultrafiltration (UF) membrane fouling. To systematically understand the effect of proteins, regenerated cellulose UF membrane (commonly used for protein separation) performance was investigated in the presence of bovine serum albumin (BSA) under various water conditions. Results showed that although trypsin enhanced the membrane flux via proteolysis, catalysis took a long time. Membrane fouling was alleviated at high solution pH and low water temperature owing to the strong electrostatic repulsion force among BSA molecules. Both Na+ and Ca2+ could increase membrane flux. However, Ca2+ played a bridging role between adjacent BSA molecules, whereas membrane fouling was alleviated via a hydration repulsion force with Na+. The order of influence on membrane fouling was as follows: Ca2+ concentration > Na+ concentration > pH > temperature > trypsin concentration. Furthermore, a polyvinylidene fluoride UF membrane experiment showed that Ca2+ could reduce the fouling induced by BSA. Thus, the differences in UF membrane performance will have application potential for alleviating UF membrane fouling induced by proteins during water treatment.
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Affiliation(s)
- Yanyan Ding
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Baiwen Ma
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
| | - Huijuan Liu
- University of Chinese Academy of Sciences, Beijing 100049, China; State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Jiuhui Qu
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
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Ma B, Qi J, Wang X, Ma M, Miao S, Li W, Liu R, Liu H, Qu J. Moderate KMnO 4-Fe(II) pre-oxidation for alleviating ultrafiltration membrane fouling by algae during drinking water treatment. WATER RESEARCH 2018; 142:96-104. [PMID: 29864651 DOI: 10.1016/j.watres.2018.05.031] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2018] [Revised: 05/14/2018] [Accepted: 05/17/2018] [Indexed: 06/08/2023]
Abstract
Although ultrafiltration (UF) membranes are highly beneficial for removing algae, the removal process causes serious UF membrane fouling. To avoid the unfavorable effects of algal cells that have been damaged by oxidants, our previous study reported a novel, moderate pre-oxidation method (KMnO4-Fe(II) process) that aimed to achieve a balance between the release of intracellular organic matter and enhanced algae removal. This study further investigated the performance of a UF membrane with KMnO4-Fe(II) pretreatment in the presence of algae-laden reservoir water after a long running time. We found that algae could be completely removed, membrane fouling was significantly alleviated, and the overall performance was much better than that of Fe(III) coagulation alone. The transmembrane pressure (TMP) during Fe(III) coagulation increased to 42.8 kPa, however, that of the KMnO4-Fe(II) process only increased to 25.1 kPa for after running for 90 d. The slower transmembrane pressure was attributed to the larger floc size, higher surface activity, and inactivation of algae. Although there was little effect on microorganism development, lower microorganism abundance (20.7%) was observed during the KMnO4-Fe(II) process than during coagulation alone (44.9%) due to the release of extracellular polymeric substances. We also found that the floc cake layer was easily removed by washing, and many of the original membrane pores were clearly observed. Further analysis demonstrated that the effluent quality was excellent, especially its turbidity, chromaticity, and Mn and Fe concentrations. Based on the outstanding UF membrane performance, it may be concluded that the KMnO4-Fe(II) process exhibits considerable potential for application in the treatment of algae-laden water.
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Affiliation(s)
- Baiwen Ma
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Jing Qi
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Xing Wang
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Min Ma
- Technology Institute of Beijing Waterworks Group Co., Ltd., Beijing 100012, China; Beijing Engineering Research Center for Drinking Water Quality, Beijing 100012, China
| | - Shiyu Miao
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wenjiang Li
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Ruiping Liu
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
| | - Huijuan Liu
- University of Chinese Academy of Sciences, Beijing 100049, China; State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Jiuhui Qu
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
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