1
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Hammond CR, Loge FJ. Wastewater treatment with microalgal-bacterial aggregates: The tradeoff between energy savings and footprint requirements. Bioresour Technol 2024; 395:130270. [PMID: 38158093 DOI: 10.1016/j.biortech.2023.130270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 12/26/2023] [Accepted: 12/26/2023] [Indexed: 01/03/2024]
Abstract
Microalgal-bacterial aggregates (MBAs) have recently attracted significant attention as a potential replacement for conventional, suspended-growth wastewater treatment processes. This article evaluates MBAs for full-scale implementation from the perspective of oxygen supply, land use, and energy savings. The results suggest that under ideal conditions, photosynthesis and atmospheric diffusion would provide at most only 2.7% of the oxygen demand in a conventionally designed, nitrifying activated sludge process, which is equivalent to approximately 1.5% of typical treatment plant-wide energy requirements. The results also suggest that a wastewater treatment process using MBAs and relying on solar photosynthesis and atmospheric diffusion for oxygen would have nearly the same footprint as an equivalent well-mixed wastewater treatment pond. While photosynthesis and passive atmospheric diffusion are capable of providing significant oxygen for suspended-growth wastewater treatment processes, the tradeoffs between footprint requirements and energy savings should be carefully considered.
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Affiliation(s)
- Charles R Hammond
- University of California, Davis, Department of Civil and Environmental Engineering, 1 Shields Avenue, Davis, CA 95616, USA
| | - Frank J Loge
- University of California, Davis, Department of Civil and Environmental Engineering, 1 Shields Avenue, Davis, CA 95616, USA.
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2
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Zhao J, Yang L, Yang J, Zhang H, Wang H, Liu D, Wang J, Cheng X, Zhu X, Liang H. Overlooked flocs in electrocoagulation-based ultrafiltration systems: A new understanding of the structural interfacial properties. Water Res 2023; 246:120675. [PMID: 37827039 DOI: 10.1016/j.watres.2023.120675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 09/25/2023] [Accepted: 09/26/2023] [Indexed: 10/14/2023]
Abstract
An integrated ferrate-induced electrocoagulation-ultrafiltration (FECUF) process is proposed to cope with the growing demand for water treatment. Although flocs formed during the electrocoagulation (EC) process are useful for contaminant reduction and mitigation of membrane fouling, few studies have been focused on their structures and properties. Herein, we investigated the formation and structural transformations of flocs and their responses to organic matter, as well as the relationships between their interfacial properties and membrane fouling mitigation. It was found that ferrate contributed to the fast formation of flocs during the ferrate-induced electrocoagulation (FEC) process, which accelerated the FECUF process. Physicochemical analyses indicated that the flocs formed in the FEC process were mainly composed of Fe(III)-(hydr)oxides with abundant hydroxyl groups and poor crystallinity, which allowed complexation with NOM. Therefore, the mobilities of the NOM and the soluble coagulant ions were reduced. The responses of flocs to NOM suggested that the period of 0-20 min resulted in the most efficient NOM removal. In addition, two patterns revealed the relationships between the interfacial properties of the small colloidal particles (SCPs) and the membrane filtration performance: i) the decline in the initial flux was closely related to the composition (gel-type substances or metal-(hydr)oxides) of the SCPs and ii) the steady-state flux was influenced by the energy barrier between the SCPs. However, when the SCPs had the same composition, the interfacial properties influenced both the initial flux and the steady-state flux. This study provides an alternative FECUF process for intensive upgrades of centralized water treatment systems.
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Affiliation(s)
- Jing Zhao
- State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), Harbin Institute of Technology, 73 Huanghe Road, Nangang District, Harbin 150090, PR China
| | - Liu Yang
- State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), Harbin Institute of Technology, 73 Huanghe Road, Nangang District, Harbin 150090, PR China
| | - Jiaxuan Yang
- State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), Harbin Institute of Technology, 73 Huanghe Road, Nangang District, Harbin 150090, PR China
| | - Han Zhang
- State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), Harbin Institute of Technology, 73 Huanghe Road, Nangang District, Harbin 150090, PR China
| | - Hesong Wang
- State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), Harbin Institute of Technology, 73 Huanghe Road, Nangang District, Harbin 150090, PR China
| | - Dongqing Liu
- State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), Harbin Institute of Technology, 73 Huanghe Road, Nangang District, Harbin 150090, PR China
| | - Jinlong Wang
- State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), Harbin Institute of Technology, 73 Huanghe Road, Nangang District, Harbin 150090, PR China.
| | - Xiaoxiang Cheng
- School of Municipal and Environmental Engineering, Shandong Jianzhu University, Jinan 250101, PR China
| | - Xuewu Zhu
- School of Municipal and Environmental Engineering, Shandong Jianzhu University, Jinan 250101, PR China
| | - Heng Liang
- State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), Harbin Institute of Technology, 73 Huanghe Road, Nangang District, Harbin 150090, PR China
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3
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Wen ZH, Zhang SS, Zhao P, Hang ZY, He ZW, Yu HQ, Li ZH. Roles of high/low nucleic acid bacteria in flocs and probing their dynamic migrations with respirogram. Sci Total Environ 2023; 895:165108. [PMID: 37356771 DOI: 10.1016/j.scitotenv.2023.165108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 06/09/2023] [Accepted: 06/22/2023] [Indexed: 06/27/2023]
Abstract
Bacterial migration is crucial for the stability of activated sludge but rarely reported. The static distribution was explored by changes in bacteria concentration with extracellular polymeric substances (EPS) extractions. Next, denitrification and aeration were conducted as normal running conditions for examining the bacterial migration between floc-attached and dispersed growth. Above observations were further explored by conducting copper ion (Cu2+) shock as an extreme running condition. After extracting EPS, low nucleic acid (LNA) bacteria migrated from the sludge to the supernatant primarily, and high nucleic acid (HNA) bacteria remained in the residual sludge, suggesting that HNA bacteria mainly distributed inside the sludge while LNA bacteria outside the sludge. During the denitrification process, LNA bacteria migrated out of flocs, which increased by 6.94 × 106 events/mL in the supernatant. During the feast phase of aeration, LNA bacteria grew attached to flocs, causing the increased flocs diameter from 45.60 to 47.40 μm. During the following aerobic famine phase, LNA bacteria grew dispersedly, but HNA bacteria remained unchanged. However, a further severe famine phase drove HNA bacteria to be dispersed, breaking flocs with the decreased diameter from 48.10 to 46.50 μm. When the Cu2+ shock was employed, LNA and HNA bacteria increased but the LNA/HNA ratio decreased in the supernatant, indicating more HNA bacteria migrating to the dispersed phase. From a structural perspective, HNA bacteria distributed inside the sludge and functioned as the backbone of flocs, undertaking the maintenance of flocs stability primarily; while LNA bacteria distributed outside the sludge and functioned as filling materials, having a secondary influence on flocs stability. These processes were also probed by respirogram exactly, correlating the system-scale measurement and microscale migrations and providing an early warning signal under abnormal circumstances. The processed HNA-backbone theory is promising for regulating the stability of activated sludge based on bacterial migrations.
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Affiliation(s)
- Zheng-Hong Wen
- Key Laboratory of Northwest Water Resource, Environment, and Ecology, MOE, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Shuang-Shuang Zhang
- Key Laboratory of Northwest Water Resource, Environment, and Ecology, MOE, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Pian Zhao
- Key Laboratory of Northwest Water Resource, Environment, and Ecology, MOE, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Zhen-Yu Hang
- Key Laboratory of Northwest Water Resource, Environment, and Ecology, MOE, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Zhang-Wei He
- Key Laboratory of Northwest Water Resource, Environment, and Ecology, MOE, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Han-Qing Yu
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei 230026, China
| | - Zhi-Hua Li
- Key Laboratory of Northwest Water Resource, Environment, and Ecology, MOE, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Xi'an Key Laboratory of Intelligent Equipment Technology for Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China.
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4
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Shan LL, Tan Z, Chen Y, Wang RS, Zhang M, Pang CL, Cui YH, Liao ZM, Ma HQ, Zhu ZB. Biodegradability enhancement of waste lubricating oil regeneration wastewater using electrocoagulation pretreatment. Environ Sci Pollut Res Int 2023; 30:106421-106430. [PMID: 37728675 DOI: 10.1007/s11356-023-29841-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 09/07/2023] [Indexed: 09/21/2023]
Abstract
As a sustainable management of fossil fuel resources and ecological environment protection, recycling used lubricating oil has received widespread attention. However, large amounts of waste lubricating-oil regeneration wastewater (WLORW) are inevitably produced in the recycling process, and challenges are faced by traditional biological treatment of WLORW. Thus, this study investigated the effectiveness of electrocoagulation (EC) as pretreatment and its removal mechanism. The electrolysis parameters (current density, initial pH, and inter-electrode distance) were considered, and maximal 60.06% of oil removal was achieved at a current density of 15 mA/cm2, initial pH of 7, and an inter-electrode distance of 2 cm. The dispersed oil of WLORW was relatively easily removed, and most of the oil removal was contributed by emulsified oil within 5-10 μm. Gas chromatography-mass spectrometry (GC-MS) analysis revealed that effective removal of the biorefractory organic compounds could contribute to the improvement of biodegradability of WLORW. Thus, the 5-day biochemical oxygen demand/chemical oxygen demand ratio (BOD5/COD) was significantly enhanced by 4.31 times, which highly benefits future biological treatment. The routes of WLORW removal could be concluded as charge neutralization, adsorption bridging, sweep flocculation, and air flotation. The results demonstrate that EC has potential as an effective pretreatment technology for WLORW biological treatment.
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Affiliation(s)
- Li-Li Shan
- School of Civil Engineering and Architecture, East China Jiao Tong University, Nanchang, 330013, China
- Jiangxi JDL Environmental Protection Co., Ltd, Nanchang, 330199, China
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Zhao Tan
- School of Civil Engineering and Architecture, East China Jiao Tong University, Nanchang, 330013, China
| | - Yu Chen
- School of Civil Engineering and Architecture, East China Jiao Tong University, Nanchang, 330013, China
| | - Ruo-Shan Wang
- School of Civil Engineering and Architecture, East China Jiao Tong University, Nanchang, 330013, China
| | - Meng Zhang
- Jiangxi Academy of Environmental Sciences, Nanchang, 330039, China
| | - Chang-Long Pang
- Jiangxi ZXDH Environmental Protection Industry Tecnology Institute Co., Ltd, Nanchang, 330000, China
| | - Yu-Hong Cui
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Zhi-Min Liao
- Jiangxi JDL Environmental Protection Co., Ltd, Nanchang, 330199, China
| | - Hong-Qiang Ma
- School of Civil Engineering and Architecture, East China Jiao Tong University, Nanchang, 330013, China
| | - Ze-Bing Zhu
- School of Civil Engineering and Architecture, East China Jiao Tong University, Nanchang, 330013, China.
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5
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Song Q, Yang B, Liu M, Song S, Graham N, Yu W. Floc aging: Crystallization and improving low molecular weight organic removal in re-coagulation. Water Res 2023; 243:120328. [PMID: 37459797 DOI: 10.1016/j.watres.2023.120328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 06/26/2023] [Accepted: 07/07/2023] [Indexed: 09/07/2023]
Abstract
Iron coagulants have been used extensively in drinking water treatment. This typically produces substantial quantities of insoluble iron hydrolysis products which interact with natural and anthropogenic organic substances during the coagulation process. Previous studies have shown that the removal of low molecular weight (MW) organics is relatively poor by coagulation, which leads to their presence during disinfection, with the formation of halogenated byproducts, and in treated water supplies as potentially biodegradable material. Currently, there is little knowledge about the changes that occur in the nature of coagulant flocs as they age with time and how such changes affect interactions with organic matter, especially low MW organics. To improve this deficiency, this study has investigated the variation of aged flocs obtained from two commonly used iron salts and their impact on representative organic contaminants, natural organic matter (NOM) and tetracycline antibiotic (TC), in a real surface water. It was found that aging resulted in increasing crystallization of the flocs, which can play a beneficial role in activating persulfate oxidant to remove the representative organics. Furthermore, acidification was also found to further improve the removal of low MW natural organics and tetracycline. In addition, the results showed that the low MW fractions of NOM (<1 K Dalton) were substantially removed by the aging flocs. These results are in marked contrast to the poor removal of low MW organic substances by conventional coagulation, with or without added oxidants, and show that aged flocs have a high potential of reuse for re-coagulation and activation of oxidants to reduce low MW organics, and enhance drinking water quality.
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Affiliation(s)
- Qingyun Song
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Bingqian Yang
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Mengjie Liu
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shian Song
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Nigel Graham
- Department of Civil and Environmental Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom
| | - Wenzheng Yu
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
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6
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He Y, Liu Y, Li X, Zhu T, Liu Y. Unveiling the roles of biofilm in reducing N 2O emission in a nitrifying integrated fixed-film activated sludge (IFAS) system. Water Res 2023; 243:120326. [PMID: 37454457 DOI: 10.1016/j.watres.2023.120326] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 06/07/2023] [Accepted: 07/06/2023] [Indexed: 07/18/2023]
Abstract
Biofilm process such as integrated fixed-film activated sludge (IFAS) system has been preliminarily found to produce less nitrous oxide (N2O) than suspended sludge system. However, the N2O emission behaviors and underlying N2O mitigation mechanism in such hybrid system remain unclear. This study therefore aims to fully unveil the roles of biofilm in reducing N2O emission in a nitrifying IFAS system with the aid of some advanced technologies such as N2O microsensor and site-preference analysis. It was found that ammonia oxidation occurred mostly in the sludge flocs (˃ 86%) and biofilm could reduce N2O emission by 43.77% in a typical operating cycle. Biofilm not only reduced nitrite accumulation in nitrification process, inhibiting N2O production via nitrifier denitrification pathway, but also served as a N2O sink, promoting the reduction of N2O via endogenous denitrification. As a result, N2O emissions from the IFAS system were 50%-83% lower than those from the solo sludge flocs. Further, more N2O emission was reduced in the presence of biofilm with decreasing the dissolved oxygen level in the range of 0.5-3.0 mg O2/L. Microbial community and key enzyme analyses revealed that biofilm had relatively high microbial diversity and unique enzyme composition, providing a reasonable explanation for the changed contributions of different N2O production pathways and reduced N2O emission.
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Affiliation(s)
- Yanying He
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, PR China
| | - Yingrui Liu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, PR China
| | - Xuecheng Li
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, PR China
| | - Tingting Zhu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, PR China
| | - Yiwen Liu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, PR China.
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7
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Walch H, Praetorius A, von der Kammer F, Hofmann T. Generation of reproducible model freshwater particulate matter analogues to study the interaction with particulate contaminants. Water Res 2023; 229:119385. [PMID: 36446178 DOI: 10.1016/j.watres.2022.119385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 11/13/2022] [Accepted: 11/17/2022] [Indexed: 06/16/2023]
Abstract
Aquatic fate models and risk assessment require experimental information on the potential of contaminants to interact with riverine suspended particulate matter (SPM). While for dissolved contaminants partition or sorption coefficients are used, the underlying assumption of chemical equilibrium is invalid for particulate contaminants, such as engineered nanomaterials, incidental nanoparticles, micro- or nanoplastics. Their interactions with SPM are governed by physicochemical forces between contaminant-particle and SPM surfaces. The availability of a standard SPM material is thus highly relevant for the development of reproducible test systems to evaluate the fate of particulate contaminants in aquatic systems. Finding suitable SPM analogues, however, is challenging considering the complex composition of natural SPM, which features floc-like structures comprising minerals and organic components from the molecular to the microorganism level. Complex composition comes with a heterogeneity in physicochemical surface properties, that cannot be neglected. We developed a procedure to generate SPM analogue flocs from components selected to represent the most abundant and crucial constituents of natural riverine SPM, and the process-relevant SPM surface characteristics regarding interactions with particulate contaminants. Four components, i.e., illite, hematite, quartz and tryptophan, combined at environmentally realistic mass-ratios, were associated to complex flocs. Flocculation was reproducible regarding floc size and fractal dimension, and multiple tests on floc resilience towards physical impacts (agitation, sedimentation-storage-resuspension, dilution) and hydrochemical changes (pH, electrolytes, dissolved organic matter concentration) confirmed their robustness. These reproducible, ready-to-use SPM analogue flocs will strongly support future research on emerging particulate contaminants.
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Affiliation(s)
- Helene Walch
- Department of Environmental Geosciences, Centre for Microbiology and Environmental Systems Science, University of Vienna, Josef-Holaubek-Platz 2, UZA II, 1090 Vienna, Austria.
| | - Antonia Praetorius
- Department of Environmental Geosciences, Centre for Microbiology and Environmental Systems Science, University of Vienna, Josef-Holaubek-Platz 2, UZA II, 1090 Vienna, Austria; Department of Ecosystem & Landscape Dynamics, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, the Netherlands.
| | - Frank von der Kammer
- Department of Environmental Geosciences, Centre for Microbiology and Environmental Systems Science, University of Vienna, Josef-Holaubek-Platz 2, UZA II, 1090 Vienna, Austria.
| | - Thilo Hofmann
- Department of Environmental Geosciences, Centre for Microbiology and Environmental Systems Science, University of Vienna, Josef-Holaubek-Platz 2, UZA II, 1090 Vienna, Austria.
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8
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Gong C, Zhang J, Ren X, He C, Han J, Zhang Z. A comparative study of electrocoagulation treatment with iron, aluminum and zinc electrodes for selenium removal from flour production wastewater. Chemosphere 2022; 303:135249. [PMID: 35691397 DOI: 10.1016/j.chemosphere.2022.135249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 05/20/2022] [Accepted: 06/03/2022] [Indexed: 06/15/2023]
Abstract
Electrocoagulation (EC) using iron (Fe), zinc (Zn) and aluminum (Al) electrodes was comparatively applied in the treatment of selenium (Se) in flour production (FP) wastewater. It was indicated that EC treatment with Fe anode obtained highest removal efficiency (79.1%) for Se in the 90 min treatment in the comparative study, which could be attributed to the superior adsorption capacity of in-situ generated iron flocs. Removal of Se resulted from electrodeposition and adsorption to in-situ generated flocs in EC treatment, and the operational conditions significantly influenced the Se removal performance in this work. The results showed the acidic condition and higher current density favored EC treatment on Se removal, EC removed up to 97.8% of Se at pH 4 under 15 mA cm-2, whereas it obtained 83.5% and 50.4% of removal efficiency at pH 7 and 10, respectively. There was competitive adsorption in the process of selenium removal, as the in-situ generated flocs effectively removed 35.6% of humic acid-like (HA-like) substance in FP wastewater after 90 min treatment. The FTIR results showed that HA-like substance mainly contained the protein water hydrogen bond, carboxylate COO antisymmetric stretching and other functional groups. Through the analysis of existence of Se in flocs and wastewater, it can be found that approximately 2.8%-3.92% of Se was removed by electrodeposition process. This study illustrated the Se removal mechanism and provided constructive suggestion for food manufacturing to the metal removal and utilization of advanced treatment.
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Affiliation(s)
- Chenhao Gong
- Institute of Resource and Environment, Beijing Academy of Science and Technology, No. 1 Gao Li Zhang Road, Beijing, 100095, China.
| | - Jian Zhang
- Institute of Resource and Environment, Beijing Academy of Science and Technology, No. 1 Gao Li Zhang Road, Beijing, 100095, China
| | - Xiaojing Ren
- Institute of Resource and Environment, Beijing Academy of Science and Technology, No. 1 Gao Li Zhang Road, Beijing, 100095, China
| | - Can He
- Institute of Resource and Environment, Beijing Academy of Science and Technology, No. 1 Gao Li Zhang Road, Beijing, 100095, China
| | - Junxing Han
- Institute of Resource and Environment, Beijing Academy of Science and Technology, No. 1 Gao Li Zhang Road, Beijing, 100095, China
| | - Zhongguo Zhang
- Institute of Resource and Environment, Beijing Academy of Science and Technology, No. 1 Gao Li Zhang Road, Beijing, 100095, China.
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9
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Téllez-Pérez SK, Wyffels S, KleinJan H, Meunier C, Gerards R. Advanced nitrogen removal from anaerobically pre-treated potato wastewater via partial nitritation-anammox in a continuous fed SBR. Chemosphere 2021; 280:130716. [PMID: 33965866 DOI: 10.1016/j.chemosphere.2021.130716] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 04/14/2021] [Accepted: 04/24/2021] [Indexed: 06/12/2023]
Abstract
Partial nitritation-anammox was carried out successfully in a continuous fed Sequencing Batch Reactor (cf-SBR), composed of 3 compartments operated in continuous mode. The reactor was operated with floccular biomass (flocs) and biofilm to remove nitrogen from the anaerobic effluent from the potato industry at different nitrogen loading rates (0.16 g TN L-1 d-1 - 0.8 g TN L-1 d-1). At the maximum nitrogen loading rate (NLR) evaluated the nitrogen removal and ammonia oxidation achieved were 62% and 74% respectively. During the evaluation of the NLR, it was observed an improvement of the characteristics of the sludge, improving the Sludge Volumetric Index (SVI) from 228 to 63 mL g-1 MLSS. Moreover, molecular analysis (qPCR) confirmed the presence of anammox bacteria on the flocs and in the biofilm from the cf-SBR. The results showed the capability of the reactor to carry out the partial nitritation-anammox in the same reactor at pilot scale. The cf-SBR was presented as a suitable and feasible technology for advanced nitrogen removal under partial nitritation and anammox conditions.
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Affiliation(s)
- S K Téllez-Pérez
- Research and Development Department, Waterleau Group NV, Wespelaar, 3150, Belgium.
| | - S Wyffels
- Research and Development Department, Waterleau Group NV, Wespelaar, 3150, Belgium
| | - H KleinJan
- CEBEDEAU, Research and Expertise Center for Water, Allée de La Découverte, 11 (B53), Quartier Polytech 1, Liège, 4000, Belgium
| | - C Meunier
- CEBEDEAU, Research and Expertise Center for Water, Allée de La Découverte, 11 (B53), Quartier Polytech 1, Liège, 4000, Belgium
| | - R Gerards
- Research and Development Department, Waterleau Group NV, Wespelaar, 3150, Belgium
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10
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Yue Y, An G, Liu L, Lin L, Jiao R, Wang D. Pre-aggregation of Al 13 in optimizing coagulation for removal of humic acid. Chemosphere 2021; 277:130268. [PMID: 33774233 DOI: 10.1016/j.chemosphere.2021.130268] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Revised: 03/01/2021] [Accepted: 03/05/2021] [Indexed: 06/12/2023]
Abstract
The effective removal of humic acid (HA) by coagulation has been extensively investigated for water treatments. However, the limitations of pH variation and excessive residual aluminum issues were still factors needed to be considered. In this study, to investigate the coagulation mechanism for removing HA by Al13 and optimize Al13 operation for removing HA, Al13 and preformed Al13 aggregates (Al13agg) were applied to remove HA at different pH conditions. The results showed that preformed Al13agg exhibited superior HA removal performance than Al13 due to its wide pH range and low residual Al level. During coagulation, Al13 and Al13agg interacted with HA in their original status, but the DSlope325-375 difference implied that the complexation capacity between HA and Al13agg was stronger than Al13. The new peaks of HPSEC representing larger molecular weight substances were formed under acidic and neutral conditions, which indicated that HA firstly aggregated into larger complexed molecules by interacting with Al13 or its hydrolysates and was subsequently removed by forming large flocs which was completely different from Al13agg situation. Therefore, the different coagulation mechanisms played the roles in HA removal for Al13 and Al13agg which were studied in this paper. It was believed that the complexation and charge neutralization effects dominated coagulation process for Al13 while sweep flocculation and adsorption coagulation were main driving force for Al13agg in HA removing. This work provides significant understanding of HA removal by Al13 and Al13agg coagulation, which can help to design and optimize the high efficiency coagulant based on Al polycations.
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Affiliation(s)
- Ye Yue
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Guangyu An
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China.
| | - Libing Liu
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Leiming Lin
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ruyuan Jiao
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; Yangtze River Delta Branch, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Yiwu, Zhejiang, 322000, China
| | - Dongsheng Wang
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China; Yangtze River Delta Branch, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Yiwu, Zhejiang, 322000, China.
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11
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Xue W, Jian M, Lin T, Ma B, Wu R, Li X. A novel strategy to alleviate ultrafiltration membrane fouling by rotating membrane module. Chemosphere 2020; 260:127535. [PMID: 32683026 DOI: 10.1016/j.chemosphere.2020.127535] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 06/18/2020] [Accepted: 06/24/2020] [Indexed: 06/11/2023]
Abstract
Integrated ultrafiltration (UF) membrane technology has attracted extensive attention in drinking water treatment due to its excellent performance and small footprint. However, membrane modules normally are static in membrane tanks, which cause a gradual increase in the cake layer thickness over time, thus resulting in severe membrane fouling. To overcome this shortcoming, we report an effective strategy to regulate cake layer thickness by rotating the membrane module in the presence of flocs. The results showed that the cake layer thickness can be effectively reduced because of the floc looseness, resulting in the alleviation of membrane fouling. The higher the module rotation speed, the higher the flow velocity in the membrane tank and the larger the shearing force on the cake layer surface. As a result, the membrane fouling was considerably mitigated, and it was interesting that the pollutant removal efficiency was hardly influenced. With module rotation, we found that acid solutions displayed a better performance in removing pollutants (even low molecular weight pollutants) and alleviating membrane fouling compared to the alkaline conditions because of the smaller floc size, larger floc specific surface area, and higher floc positive charge. Additionally, an excellent UF membrane performance was also observed with the raw water taken from the South-North water in China. Collectively, this study demonstrated that floc-based cake layers can be effectively regulated with module rotation, which has a great potential in drinking water treatment application, particularly in small water plants.
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Affiliation(s)
- 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
| | - Meipeng Jian
- Department of Chemical Engineering, Monash University, Clayton, Victoria, 3800, Australia
| | - Tao Lin
- Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Hohai University, Nanjing, 210098, China; College of Environment, Hohai University, Nanjing, 210098, China
| | - Baiwen Ma
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China.
| | - Ruijun Wu
- State Key Laboratory of Membrane Materials and Membrane Applications, Tianjin Motimo Membrane Technology Co., Ltd., Tianjin, 300457, China
| | - Xingchun Li
- State Key Laboratory of Petroleum Pollution Control, CNPC Research Institute of Safety & Environment Technology, Beijing, 102206, China.
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12
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Layer M, Bock K, Ranzinger F, Horn H, Morgenroth E, Derlon N. Particulate substrate retention in plug-flow and fully-mixed conditions during operation of aerobic granular sludge systems. Water Res X 2020; 9:100075. [PMID: 33196033 PMCID: PMC7645637 DOI: 10.1016/j.wroa.2020.100075] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 10/03/2020] [Accepted: 10/19/2020] [Indexed: 06/11/2023]
Abstract
Particulate substrate (XB) is the major organic substrate fraction in most municipal wastewaters. However, the impact of XB on aerobic granular sludge (AGS) systems is not fully understood. This study evaluated the physical retention of XB in AGS sequencing batch reactor (SBR) during anaerobic plug-flow and then aerobic fully-mixed conditions. The influence of different sludge types and operational variables on the extent and mechanisms of XB retention in AGS SBR were evaluated. XB mass-balancing and magnetic resonance imaging (MRI) were applied. During the anaerobic plug-flow feeding, most XB was retained in the first few cm of the settled sludge bed within the interstitial voids, where XB settled and accumulated ultimately resulting in the formation of a filter-cake. Sedimentation and surface filtration were thus the dominant XB retention mechanisms during plug-flow conditions, indicating that contact and attachment of XB to the biomass was limited. XB retention was variable and influenced by the XB influent concentration, sludge bed composition and upflow feeding velocity (vww). XB retention increased with larger XB influent concentrations and lower vww, which demonstrated the importance of sedimentation on XB retention during plug-flow conditions. Hence, large fractions of influent XB likely re-suspended during aerobic fully-mixed conditions, where XB then preferentially and rapidly attached to the flocs. During fully-mixed conditions, increasing floc fractions, longer mixing times and larger XB concentrations increased XB retention. Elevated XB retention was observed after short mixing times < 60 min when flocs were present, and the contribution of flocs towards XB retention was even more pronounced for short mixing times < 5 min. Overall, our results suggest that flocs occupy an environmental niche that results from the availability of XB during aerobic fully-mixed conditions of AGS SBR. Therefore, a complete wash-out of flocs is not desirable in AGS systems treating municipal wastewater.
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Affiliation(s)
- M. Layer
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, 8600, Dübendorf, Switzerland
- ETH Zürich, Institute of Environmental Engineering, 8093, Zürich, Switzerland
| | - K. Bock
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, 8600, Dübendorf, Switzerland
| | - F. Ranzinger
- Engler-Bunte-Institut, Karlsruhe Institute of Technology, 76131, Karlsruhe, Germany
| | - H. Horn
- Engler-Bunte-Institut, Karlsruhe Institute of Technology, 76131, Karlsruhe, Germany
| | - E. Morgenroth
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, 8600, Dübendorf, Switzerland
- ETH Zürich, Institute of Environmental Engineering, 8093, Zürich, Switzerland
| | - N. Derlon
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, 8600, Dübendorf, Switzerland
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13
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Zhuang JL, Zhou YY, Liu YD, Li W. Flocs are the main source of nitrous oxide in a high-rate anammox granular sludge reactor: insights from metagenomics and fed-batch experiments. Water Res 2020; 186:116321. [PMID: 32861184 DOI: 10.1016/j.watres.2020.116321] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 07/10/2020] [Accepted: 08/19/2020] [Indexed: 06/11/2023]
Abstract
Nitrous oxide (N2O) emissions from anammox-based processes are well documented but insight into source of the N2O emission in high-rate anammox granular sludge reactors (AGSR) is limited. In this study, metagenomics and fed-batch experiments were applied to investigate the relative contributions of anammox granules and flocs to N2O production in a high-rate AGSR. Flocs, which constitute only ~10% of total biomass contributed about 60% of the total N2O production. Granules, the main contributor of nitrogen removal (~95%), were responsible for the remaining ~40% of N2O production. This result is inconsistent with reads-based analysis that found the gene encoding clade II type nitrous oxide reductase (nosZII) had similar abundances in both granules and flocs. Another notable trend observed was the relatively higher abundance of the gene for NO-producing nitrite reductase (nir) in comparison to the gene for the nitric oxide reductase gene (nor) in both granules and flocs, indicating nitric oxide (NO) may accumulate in the AGSR. This is significant since NO and N2O pulse assays demonstrated that NO could lead to N2O production from both granules and flocs. However, since anammox bacteria, which were shown to be in higher abundance in granules than in flocs, have the capacity to scavenge NO this provides a mechanism by which its inhibitory effects can be mitigated, limiting N2O release from the granules, consistent with experimental observation. These results demonstrate flocs are the main source of N2O emission in AGSR and provide lab-scale evidence that NO-dependent anammox can mitigate N2O emission.
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Affiliation(s)
- Jin-Long Zhuang
- National Engineering Laboratory for Industrial Wastewater Treatment, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, China; State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, China
| | - Yuan-Yuan Zhou
- National Engineering Laboratory for Industrial Wastewater Treatment, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, China; State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, China
| | - Yong-di Liu
- National Engineering Laboratory for Industrial Wastewater Treatment, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, China; State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, China
| | - Wei Li
- National Engineering Laboratory for Industrial Wastewater Treatment, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, China; State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, China.
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14
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Liu W, Song J, Wang J, Wu P, Shen Y, Yang D. Comparing nitrite-limited and ammonium-limited anammox processes treating low-strength wastewater: Functional and population heterogeneity. Chemosphere 2020; 258:127290. [PMID: 32535448 DOI: 10.1016/j.chemosphere.2020.127290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 05/12/2020] [Accepted: 06/01/2020] [Indexed: 06/11/2023]
Abstract
Biomass segregation between granules/biofilm and flocs is widespread in anammox-based processes. The segregation of biomass allows for easy control of processes stability. The goal of this study is to understand the biomass segregation in two anoxic anammox reactors respectively operated in nitrite-limited (RNO2) and ammonium-limited (RNH4) modes treating low-strength wastewater at 20 °C. Results showed that size-based biomass segregation was developed in both reactors. But the functional and population heterogeneity was more significant in the ammonium-limited anammox reactor. The activity and abundance of anammox bacteria in large granules were significantly higher than that in flocs under the ammonium-limited conditions. The large granules played a major role in nitrogen removal in RNH4. By contrast, both large granules and small flocs contributed significantly to the nitrogen loss in the nitrite-limited anammox reactor, since a large number of anammox bacteria existed in both granules and flocs. Besides, a number of Nitrospira-like NOB were also detected in both anoxic anammox reactors, which primarily inhabited in flocs seemingly droved by the availability of oxygen. But the abundance of Nitrospira in RNH4 was much higher than that in RNO2. All these results suggested that selective flocs removal would be necessary for RNH4 to improve its anammox performance but non-essential for RNO2. The two anammox reactors shared the predominant anammox species with the closest relative to Ca. Brocadia sp. 40 (98%). Unexpectedly, the anammox species grew faster in RNH4. But the microbial diversity and evenness was much greater in RNO2, suggesting its higher functional stability.
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Affiliation(s)
- Wenru Liu
- National & Local Joint Engineering Laboratory for Municipal Sewage Resource Utilization Technology, Suzhou University of Science and Technology, Suzhou, 215009, China; School of Environmental Science and Engineering, Suzhou University of Science and Technology, Suzhou, 215009, China.
| | - Jiajun Song
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, Suzhou, 215009, China
| | - Jianfang Wang
- National & Local Joint Engineering Laboratory for Municipal Sewage Resource Utilization Technology, Suzhou University of Science and Technology, Suzhou, 215009, China; School of Environmental Science and Engineering, Suzhou University of Science and Technology, Suzhou, 215009, China
| | - Peng Wu
- National & Local Joint Engineering Laboratory for Municipal Sewage Resource Utilization Technology, Suzhou University of Science and Technology, Suzhou, 215009, China; School of Environmental Science and Engineering, Suzhou University of Science and Technology, Suzhou, 215009, China.
| | - Yaoliang Shen
- National & Local Joint Engineering Laboratory for Municipal Sewage Resource Utilization Technology, Suzhou University of Science and Technology, Suzhou, 215009, China; School of Environmental Science and Engineering, Suzhou University of Science and Technology, Suzhou, 215009, China
| | - Dianhai Yang
- State Key Laboratory of Pollution Control and Resources Reuse, Tongji University, Shanghai, 200092, China
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15
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Wang P, Jiao R, Liu L, Xiao F, An G, Wang D. Optimized coagulation pathway of Al 13: Effect of in-situ Aggregation of Al 13. Chemosphere 2019; 230:76-83. [PMID: 31102874 DOI: 10.1016/j.chemosphere.2019.05.053] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 04/24/2019] [Accepted: 05/06/2019] [Indexed: 06/09/2023]
Abstract
The coagulation mechanism for removing particles by Al13 has been extensively investigated for water treatments. It was widely accepted that Al13 played important roles in coagulation mainly by charge neutralization and electrostatic patch. However, the discovery of Al13 aggregates (Al13agg) in flocs indicated that the real coagulation process should be different from the previous understanding, including when Al13agg were generated and how it interacted with negative particles. The aggregation process of Al13 during coagulation and its micro-interfacial effect on particle coagulation remains to be explored. In this study, to investigate the aggregation of Al13 and its effect on coagulation performance, two parallel coagulation jar tests were conducted on silica suspensions by preformed Al13agg and Al13, respectively. The results showed that optimized coagulation for particle removal by Al13 occurred from pH 7 to pH 9, which was dominated by the in-situ aggregation of Al13. The results confirmed that Al13agg were both present in flocs generated in two tests, however, the morphology and distribution of surface Al of flocs were different for two tests. The in-situ formed Al13agg covered all over the silica particles in flocs, resulting in compact structure with rough surfaces, while the preformed Al13agg mainly distributed on joint sites between particles, generating denser flocs with smooth surfaces. This difference verified that the in-situ aggregation of Al13 was the key factor to optimized particle coagulation. The overall optimized particle coagulation by Al13 should undergo the following pathway: charge neutralization - in-situ aggregation of Al13 - inter-particle bridging.
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Affiliation(s)
- Pin Wang
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ruyuan Jiao
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Libing Liu
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Feng Xiao
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Guangyu An
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
| | - Dongsheng Wang
- State Key Laboratory of Environmental Aquatic Chemistry, 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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16
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Yang S, Peng Y, Zhang L, Zhang Q, Li J, Wang X. Autotrophic nitrogen removal in an integrated fixed-biofilm activated sludge (IFAS) reactor: Anammox bacteria enriched in the flocs have been overlooked. Bioresour Technol 2019; 288:121512. [PMID: 31129521 DOI: 10.1016/j.biortech.2019.121512] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2019] [Revised: 05/11/2019] [Accepted: 05/17/2019] [Indexed: 06/09/2023]
Abstract
In this study, an autotrophic nitrogen removal process was established using an integrated fixed-biofilm activated sludge (IFAS) reactor treated with high ammonium wastewater. A nitrogen removal rate (NRR) of 2.78 kg N/(m3·d) was obtained during the 206-day operation. Moreover, during the stable period, the large flocs (D > 0.2 mm) had a significantly higher abundance of anammox bacteria than the small flocs (D < 0.2 mm) and biofilm, resulting in 51% of the anammox bacteria being located in the flocs. The result indicates that anammox bacteria can be enriched in the flocs and in the biofilm, which has been rarely reported for IFAS reactors. In addition, the large flocs are likely formed through biofilm detachment since the microbial community was similar for the two kinds of biomass. Overall, the role of flocs in IFAS reactors are complicated and their contribution to the anammox reaction have been overlooked thus far.
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Affiliation(s)
- Shenhua Yang
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Engineering Research Center of Beijing, Beijing University of Technology, Beijing 100124, PR China
| | - Yongzhen Peng
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Engineering Research Center of Beijing, Beijing University of Technology, Beijing 100124, PR China
| | - Liang Zhang
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Engineering Research Center of Beijing, Beijing University of Technology, Beijing 100124, PR China.
| | - Qiong Zhang
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Engineering Research Center of Beijing, Beijing University of Technology, Beijing 100124, PR China
| | - Jialin Li
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Engineering Research Center of Beijing, Beijing University of Technology, Beijing 100124, PR China
| | - Xiaoling Wang
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Engineering Research Center of Beijing, Beijing University of Technology, Beijing 100124, PR China
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17
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Yu W, Xu L, Lei K, Gregory J. Effect of crystallization of settled aluminum hydroxide precipitate on "dissolved Al". Water Res 2018; 143:346-354. [PMID: 29986244 DOI: 10.1016/j.watres.2018.06.063] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2018] [Revised: 06/20/2018] [Accepted: 06/26/2018] [Indexed: 06/08/2023]
Abstract
When aluminum salts are added to water at around neutral pH, a precipitate of Al hydroxide is formed very rapidly. Initially the precipitate is in the form of nano-scale primary particles, which then aggregate to form flocs. The nature of the flocs depends greatly on the solution composition, for instance on the presence of humic acid (HA), which not only increases the size of the primary nanoparticles, but also decreases the connection points between them. The nanoparticles become smaller with aging, both with and without HA, as a result of crystallization. The aggregated amorphous nanoparticles (settled flocs) undergo a room temperature structural modification best characterized as a disorder-to-order transition, following elimination of water. During this process, the apparent Al concentration in the supernatant of water increases with age. The "dissolved Al" concentration in the supernatant becomes higher with increasing pH and, to some extent, in the presence of HA. However, it can be shown that the "dissolved Al" in the supernatant exists in the form of crystalline nano-particles or larger clusters, which are detached from the settled flocs. TEM results confirmed that HA only adsorbed on the surface of nano-particles during the coagulation process, which shows precipitate nanoparticles formed firstly during sweep coagulation before the adsorption of HA or complexed Al3+-HA. However, the adsorbed outer layer of HA does not change the crystallization process for the inner part of nano-particles. This laboratory study may have implications for the release of Al from sediments into lake water, following addition of coagulants to lower phosphorus concentrations.
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Affiliation(s)
- Wenzheng Yu
- Key Laboratory of Drinking Water Science and Technology, Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; Department of Civil and Environmental Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK.
| | - Lei Xu
- Centre for Water Resources Research (CWRR), School of Civil, Structural and Environmental Engineering, University College Dublin, Newstead Building, Belfield, Dublin 4, Ireland.
| | - Kaiyu Lei
- BGI-Shenzhen, Shenzhen 518083, China; Hammersmith Hospital, Imperial College London, Ducan Road, London W12 0NN, UK.
| | - John Gregory
- Department of Civil, Environmental and Geomatic Engineering, University College London, Gower Street, London WC1E 6BT, UK.
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18
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Wang Z, Wang Y, Yu C, Zhao Y, Fan M, Gao B. The removal of silver nanoparticle by titanium tetrachloride and modified sodium alginate composite coagulants: floc properties, membrane fouling, and floc recycle. Environ Sci Pollut Res Int 2018; 25:21058-21069. [PMID: 29767310 DOI: 10.1007/s11356-018-2240-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 05/04/2018] [Indexed: 06/08/2023]
Abstract
In this study, a modified sodium alginate (MSA) composited with TiCl4 was used to treat the synthetic Ag nanoparticles (AgNPs) water in coagulation-ultrafiltration process. The floc properties and membrane fouling of TiCl4 and MSA composite coagulants (TiCl4 + MSA) were investigated by a laser diffraction instrument and ultrafiltration fouling model. The recycle of the AgNP-containing flocs was evaluated by XRD and photocatalytic experiments. The results showed that TiCl4 + MSA could achieve better coagulation performance than TiCl4 alone with AgNP and DOC removal up to 97 and 59% at the optimum condition (pH = 5 and dosage = 12 mg TiCl4/L). TiCl4 + MSA produced larger and looser flocs than TiCl4 and TiCl4 + SA composite coagulant (TiCl4 + SA), which was benefit for the inhibition of subsequence membrane fouling. The strongly attached external fouling resistance (Ref-s) and the reversible internal fouling resistance (Rif-r) of TiCl4 + MSA were only 43 and 39.2% of those achieved by TiCl4 at the optimal coagulation condition. Besides, the adopted AgCl-TiO2 could be recycled from AgNP-containing flocs. And MSA could promote the form of TiO2 anatase. It gives us a possible way for silver nanoparticle recycle.
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Affiliation(s)
- Ziyang Wang
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan, 250100, China
| | - Yan Wang
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan, 250100, China.
| | - Cong Yu
- Department of Laboratory Medicine, University of Washington, Seattle, WA, 98104, USA
| | - Yanxia Zhao
- Key Laboratory for Special Functional Aggregated Materials of Education Ministry, School of Chemistry and Chemical Engineering, Shandong University, Jinan, 250100, China
| | - Meixia Fan
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan, 250100, China
| | - Baoyu Gao
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan, 250100, China.
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19
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Walczyńska A, Sobczyk M, Fiałkowska E, Pajdak-Stós A, Fyda J, Wiąckowski K. Interaction Between a Bacterivorous Ciliate Aspidisca cicada and a Rotifer Lecane inermis: Doozers and Fraggles in Aquatic Flocs. Microb Ecol 2018; 75:569-581. [PMID: 28721506 PMCID: PMC5856895 DOI: 10.1007/s00248-017-1036-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Accepted: 07/04/2017] [Indexed: 05/22/2023]
Abstract
Activated sludge is a semi-natural habitat composed of macroaggregates made by flocculating bacteria and inhabited by numerous protozoans and metazoans, creating a complicated interactome. The activated sludge resembles the biological formation of naturally occurring floc habitats, such as "marine snow." So far, these two types of habitat have been analyzed separately, despite their similarities. We examined the effect of a bacterivorous ciliate, Aspidisca cicada, on the quality of the macroaggregate ecosystem by estimating (i) the floc characteristics, (ii) the proliferation of other bacterivores (rotifers), and (iii) the chemical processes. We found that A. cicada (i) positively affected floc quality by creating flocs of larger size; (ii) promoted the population growth of the rotifer Lecane inermis, an important biological agent in activated sludge systems; and (iii) increased the efficiency of ammonia removal while at the same time improving the oxygen conditions. The effect of A. cicada was detectable long after its disappearance from the system. We therefore claim that A. cicada is a very specialized scavenger of flocs with a key role in floc ecosystem functioning. These results may be relevant to the ecology of any natural and engineered aggregates.
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Affiliation(s)
- Aleksandra Walczyńska
- Institute of Environmental Sciences, Jagiellonian University, Gronostajowa 7, 30-387, Kraków, Poland.
| | - Mateusz Sobczyk
- Institute of Environmental Sciences, Jagiellonian University, Gronostajowa 7, 30-387, Kraków, Poland
| | - Edyta Fiałkowska
- Institute of Environmental Sciences, Jagiellonian University, Gronostajowa 7, 30-387, Kraków, Poland
| | - Agnieszka Pajdak-Stós
- Institute of Environmental Sciences, Jagiellonian University, Gronostajowa 7, 30-387, Kraków, Poland
| | - Janusz Fyda
- Institute of Environmental Sciences, Jagiellonian University, Gronostajowa 7, 30-387, Kraków, Poland
| | - Krzysztof Wiąckowski
- Institute of Environmental Sciences, Jagiellonian University, Gronostajowa 7, 30-387, Kraków, Poland
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20
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Liu W, Yang D, Chen W, Gu X. High-throughput sequencing-based microbial characterization of size fractionated biomass in an anoxic anammox reactor for low-strength wastewater at low temperatures. Bioresour Technol 2017; 231:45-52. [PMID: 28192725 DOI: 10.1016/j.biortech.2017.01.050] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 01/23/2017] [Accepted: 01/27/2017] [Indexed: 06/06/2023]
Abstract
The microbial characterization of three size-fractionated sludge obtained from a suspended-growth anoxic anammox reactor treating low-strength wastewater at low temperatures were investigated by using high-throughput sequencing. Particularly, the spatial variability in relative abundance of microorganisms involved in nitrogen metabolism were analyzed in detail. Results showed that population segregation did occur in the reactor. It was found, for the first time, that the genus Nitrotoga was enriched only in large granules (>400μm). Three anammox genus including Candidatus Jettenia, Brocadia and Kuenenia were detected. Among them, Candidatus Brocadia and Kuenenia preferred to grow in large-sized granules (>400μm), whereas Candidatus Jettenia dominated in small- and moderate-sized sludge (<400μm). The members of genus Candidatus Jettenia appeared to play the vital role in nitrogen removal, since sludge with diameters smaller than 400μm accounted for 81.55% of the total biomass. However, further studies are required to identify the activity of different-size sludge.
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Affiliation(s)
- Wenru Liu
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai, China
| | - Dianhai Yang
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai, China.
| | - Wenjing Chen
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai, China
| | - Xiao Gu
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai, China
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Liu W, Yang D. Evaluating the feasibility of ratio control strategy for achieving partial nitritation in a continuous floccular sludge reactor: Experimental demonstration. Bioresour Technol 2017; 224:94-100. [PMID: 27914786 DOI: 10.1016/j.biortech.2016.11.100] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Revised: 11/20/2016] [Accepted: 11/23/2016] [Indexed: 06/06/2023]
Abstract
To investigate the applicability of ratio control strategy to other systems, a continuous floccular sludge reactor was used in this study. It was found that nitrite accumulation was barely detected throughout 70days' investigation, being the average concentration in the effluent of 0.7±0.4mg/L. Batch experiments indicated that low dissolved oxygen (DO<0.3mg·L-1) greatly repressed the ammonium oxidizing bacteria (AOB) but only slightly inhibited the nitrite oxidizing bacteria (NOB). However, high-throughput sequencing revealed that the ratio of abundance between Nitrospira and Nitrosomonas, being the dominant NOB and AOB respectively, was considerably low (1.2%/18.7%). The weak oxygen gradients in floccular sludge and the selectively enriched K-strategist NOB Nitrospira under oxygen-limited conditions were both contributed to the failure of achieving partial nitritation; therefore, the rapid start-up of partial nitritation process based on proposed ratio control strategy is not feasible for continuous floccular sludge systems treating low-strength wastewater.
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Affiliation(s)
- Wenru Liu
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai, China
| | - Dianhai Yang
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai, China.
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Shi Y, Wells G, Morgenroth E. Microbial activity balance in size fractionated suspended growth biomass from full-scale sidestream combined nitritation-anammox reactors. Bioresour Technol 2016; 218:38-45. [PMID: 27347796 DOI: 10.1016/j.biortech.2016.06.041] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Revised: 06/06/2016] [Accepted: 06/09/2016] [Indexed: 06/06/2023]
Abstract
The purpose of this study was to determine the abundance, distribution and activity of aerobic ammonia-oxidizing bacteria (AOB) and anammox in size fractionated aggregates from full-scale suspended growth combined nitritation-anammox sidestream reactors. Plants with or without a cyclone device were also studied to assess a purported enrichment of anammox granules. Specific aerobic ammonium oxidation rates (p=0.01) and specific oxygen uptake rates (p=0.02) were significantly greater in flocs than in granules. AOB abundance measured using quantitative FISH was significantly higher in flocs than in granules (p=0.01). Conversely, anammox abundance was significantly greater in granules (p=0.03). The average ratio of anammox/AOB in systems employing hydrocyclone separation devices was 2.4, significantly higher (p=0.02) than the average ratio (0.5) in a system without a hydrocyclone. Our results demonstrate substantial functional and population-level segregation between floccular and granular fractions, and provide a key corroboration that cyclone separation devices can increase anammox levels in such systems.
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Affiliation(s)
- Yijing Shi
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Ueberlandstr. 133, 8600 Duebendorf, Switzerland; Shandong Provincial Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan 250100, China
| | - George Wells
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Ueberlandstr. 133, 8600 Duebendorf, Switzerland; Northwestern University, Department of Civil and Environmental Engineering, Evanston, IL, USA.
| | - Eberhard Morgenroth
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Ueberlandstr. 133, 8600 Duebendorf, Switzerland; ETH Zurich, Institute of Environmental Engineering, 8093 Zurich, Switzerland
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Zhu L, Zhou J, Lv M, Yu H, Zhao H, Xu X. Specific component comparison of extracellular polymeric substances (EPS) in flocs and granular sludge using EEM and SDS-PAGE. Chemosphere 2015; 121:26-32. [PMID: 25441926 DOI: 10.1016/j.chemosphere.2014.10.053] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Revised: 09/27/2014] [Accepted: 10/26/2014] [Indexed: 06/04/2023]
Abstract
Extracellular polymeric substances (EPS) plays an important role in the formation of bioaggregates such as flocs, biofilm and granular sludge. However, the role of their specific components in sludge flocculation and granulation is still unclear. Three sludge samples including the flocs, aerobic and anaerobic granular sludge were investigated in this study and the specific components in different EPS structures of loosely bound-EPS (LB-EPS) and tightly bound-EPS (TB-EPS) were analyzed. Results showed that the protein (PN) contents in LB-EPS and TB-EPS of the aerobic and anaerobic granular sludge were 33.6±9.7 and 96.8±11.9, 27.1±2.8 and 61.6±4.2 mg g(-1)VSS, respectively, which were both higher than the flocs of 8.5±1.5 and 43.1±2.7 mg g(-1)VSS. But the polysaccharide (PS) contents in the three sludges were all about 30 mg g(-1)VSS. The analysis of sludge surface charge indicated that they had a linear correlation with the PN content, which implied that PN significantly contributed to the formation of granular sludge. The results of sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) demonstrated that the molecular weight of PN in flocs was mainly distributed in 14.3-66.2 kDa, while it was 20.1-97.4 kDa in the granular sludge, which indicated that the proteins with high molecular weight favors the sludge granulation. According to the three-dimensional fluorescence (EEM) results, the aromatic protein-like and tryptophan protein-like substances were more abundant in the granular sludge than that in flocs, suggesting they are the key components in the structural stability of granular sludge.
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Affiliation(s)
- Liang Zhu
- Department of Environmental Engineering, Zhejiang University, Hangzhou 310058, China; Zhejiang Province Key Laboratory for Water Pollution Control and Environmental Safety, Hangzhou 310058, China.
| | - Jiaheng Zhou
- Department of Environmental Engineering, Zhejiang University, Hangzhou 310058, China
| | - Meile Lv
- Department of Environmental Engineering, Zhejiang University, Hangzhou 310058, China
| | - Haitian Yu
- Department of Environmental Engineering, Zhejiang University, Hangzhou 310058, China
| | - Hang Zhao
- Department of Environmental Engineering, Zhejiang University, Hangzhou 310058, China
| | - Xiangyang Xu
- Department of Environmental Engineering, Zhejiang University, Hangzhou 310058, China; Zhejiang Province Key Laboratory for Water Pollution Control and Environmental Safety, Hangzhou 310058, China
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Sun Q, Li Y, Tang T, Yuan Z, Yu CP. Removal of silver nanoparticles by coagulation processes. J Hazard Mater 2013; 261:414-420. [PMID: 23973474 DOI: 10.1016/j.jhazmat.2013.07.066] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Revised: 07/22/2013] [Accepted: 07/27/2013] [Indexed: 06/02/2023]
Abstract
Commercial use of silver nanoparticles (AgNPs) will lead to a potential route for human exposure via potable water. Coagulation followed by sedimentation, as a conventional technique in the drinking water treatment facilities, may become an important barrier to prevent human from AgNP exposures. This study investigated the removal of AgNP suspensions by four regular coagulants. In the aluminum sulfate and ferric chloride coagulation systems, the water parameters slightly affected the AgNP removal. However, in the poly aluminum chloride and polyferric sulfate coagulation systems, the optimal removal efficiencies were achieved at pH 7.5, while higher or lower of pH could reduce the AgNP removal. Besides, the increasing natural organic matter (NOM) would reduce the AgNP removal, while Ca(2+) and suspended solids concentrations would also affect the AgNP removal. In addition, results from the transmission electron microscopy and X-ray diffraction showed AgNPs or silver-containing nanoparticles were adsorbed onto the flocs. Finally, natural water samples were used to validate AgNP removal by coagulation. This study suggests that in the case of release of AgNPs into the source water, the traditional water treatment process, coagulation/sedimentation, can remove AgNPs and minimize the silver ion concentration under the well-optimized conditions.
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Affiliation(s)
- Qian Sun
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
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