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Effect of pH on anionic polyacrylamide adhesion: New insights into membrane fouling based on XDLVO analysis. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2020.114463] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Remmas N, Melidis P, Paschos G, Statiris E, Ntougias S. Protozoan indicators and extracellular polymeric substances alterations in an intermittently aerated membrane bioreactor treating mature landfill leachate. ENVIRONMENTAL TECHNOLOGY 2017; 38:53-64. [PMID: 27194208 DOI: 10.1080/09593330.2016.1190792] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Accepted: 05/12/2016] [Indexed: 06/05/2023]
Abstract
A membrane bioreactor was operated under intermittent aeration and various organic loading rates (OLR: 0.070, 0.159 and 0.291 g COD L-1 d-1) to remove carbon and nitrogen from mature landfill leachate, where external carbon source (glycerol) addition resulted in effective nitrate removal. A relative increase in soluble microbial product (SMP) over extracellular polymeric substances (EPS) was observed at the highest OLR and glycerol addition, whereas no membrane biofouling occurred. SMP (proteins and carbohydrates) and carbohydrate EPS correlated positively and negatively, respectively, with suspended solids and transmembrane pressure (TMP). Moreover, proteinous SMP significantly correlated with carbon and nitrogen load. Principal component analysis also revealed the influence of leachate organic and nitrogen content on biomass production, TMP and sessile ciliate densities. Although filamentous index (FI) was sustained at high levels (3-4), with Haliscomenobacter hydrossis being the main filamentous bacterium identified, no bulking phenomena occurred. High glycerol addition resulted in a rapid increase in sessile ciliate population. Increased Epistylis and Vorticella microstoma population was detected by microscopic examination during high glycerol addition, while a remarkable Rhogostoma population (supergroup Rhizaria) was identified by molecular techniques. The contribution of Rhizaria in nitrogen processes may lead to the dominance of Rhogostoma during landfill leachate treatment.
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Affiliation(s)
- Nikolaos Remmas
- a Laboratory of Wastewater Management and Treatment Technologies, Department of Environmental Engineering , Democritus University of Thrace , Xanthi , Greece
| | - Paraschos Melidis
- a Laboratory of Wastewater Management and Treatment Technologies, Department of Environmental Engineering , Democritus University of Thrace , Xanthi , Greece
| | - Georgios Paschos
- a Laboratory of Wastewater Management and Treatment Technologies, Department of Environmental Engineering , Democritus University of Thrace , Xanthi , Greece
| | - Evangelos Statiris
- a Laboratory of Wastewater Management and Treatment Technologies, Department of Environmental Engineering , Democritus University of Thrace , Xanthi , Greece
| | - Spyridon Ntougias
- a Laboratory of Wastewater Management and Treatment Technologies, Department of Environmental Engineering , Democritus University of Thrace , Xanthi , Greece
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Zhang Z, Wang Y, Leslie GL, Waite TD. Effect of ferric and ferrous iron addition on phosphorus removal and fouling in submerged membrane bioreactors. WATER RESEARCH 2015; 69:210-222. [PMID: 25482913 DOI: 10.1016/j.watres.2014.11.011] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2014] [Revised: 11/04/2014] [Accepted: 11/10/2014] [Indexed: 06/04/2023]
Abstract
The effect of continuously dosing membrane bioreactors (MBRs) with ferric chloride (Fe(III)) and ferrous sulphate (Fe(II)) on phosphorus (P) removal and membrane fouling is investigated here. Influent phosphorus concentrations of 10 mg/L were consistently reduced to effluent concentrations of less than 0.02 mg/L and 0.03-0.04 mg/L when an Fe(III)/P molar ratio of 4.0 and Fe/P molar ratio (for both Fe(II) and Fe(III)) of 2.0 were used, respectively. In comparison, effluent concentrations did not decrease below 1.35 mg/L in a control reactor to which iron was not added. The concentrations of supernatant organic compounds, particularly polysaccharides, were reduced significantly by iron addition. The sub-critical fouling time (tcrit) after which fouling becomes much more severe was substantially shorter with Fe(III) dosing (672 h) than with Fe(II) dosing (1200-1260 h) at Fe/P molar ratios of 2.0 while the control reactor (no iron dosing) exhibited a tcrit of 960 h. Not surprisingly, membrane fouling was substantially more severe at Fe/P ratios of 4. Fe(II) doses yielding Fe/P molar ratios of 2 or less with dosing to the aerobic chamber were found to be optimal in terms of P removal and fouling mitigation performance. In long term operation, however, the use of iron for maintaining appropriately low effluent P concentrations results in more severe irreversible fouling necessitating the application of an effective membrane cleaning regime.
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Affiliation(s)
- Zhenghua Zhang
- Water Research Centre, School of Civil and Environmental Engineering, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Yuan Wang
- Water Research Centre, School of Civil and Environmental Engineering, The University of New South Wales, Sydney, NSW 2052, Australia; UNESCO Centre for Membrane Science and Technology, School of Chemical Engineering, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Greg L Leslie
- UNESCO Centre for Membrane Science and Technology, School of Chemical Engineering, The University of New South Wales, Sydney, NSW 2052, Australia
| | - T David Waite
- Water Research Centre, School of Civil and Environmental Engineering, The University of New South Wales, Sydney, NSW 2052, Australia.
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Sanguanpak S, Chiemchaisri C, Chiemchaisri W, Yamamoto K. Effects of mixed liquor pH on membrane fouling and micro-pollutant removals in membrane bioreactors for municipal landfill leachate treatment. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2015; 72:770-778. [PMID: 26287836 DOI: 10.2166/wst.2015.274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
This research investigated the membrane fouling and micro-pollutant removals in treatment of municipal landfill leachate at various pH levels (i.e. 5.5, 6.5, 7.5, and 8.5) using membrane bioreactors. The findings revealed that membrane fouling was influenced by the pH level of mixed liquor, with pH 5.5 exhibiting the most severe membrane fouling. At pH 5.5, proteins and carbohydrates were predominant in the membrane foulants, while at pH 8.5 humic-like and inorganic substances constituted the largest proportion of the foulants on the membrane surface. The removal efficiencies of micro-pollutants (bisphenol-A; 2,6-di-tert-butylphenol and 2,6-di-tert-butyl-4-methylbutylphenol) were nevertheless insignificantly influenced by the pH levels of mixed liquor. In addition, the removal rates of the compounds at pH 5.5 were slightly lower vis-à-vis at the higher pH levels. The micro-pollutant retention on the fouled membranes was also significant and highest under the mixed liquor pH of 8.5. Furthermore, the experiments demonstrated that the varying degrees of rejection by the fouled membranes could be attributed to the alteration of foulant characteristics as a result of the pH variations.
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Affiliation(s)
- Samunya Sanguanpak
- Department of Environmental Engineering, Faculty of Engineering, Kasetsart University, Bangkok 10900 and MTEC, National Science and Technology Development Agency (NSTDA), Pathumthani 12120, Thailand
| | - Chart Chiemchaisri
- Department of Environmental Engineering, Faculty of Engineering, Kasetsart University, Bangkok 10900, Thailand E-mail:
| | - Wilai Chiemchaisri
- Department of Environmental Engineering, Faculty of Engineering, Kasetsart University, Bangkok 10900, Thailand E-mail:
| | - Kazuo Yamamoto
- Environmental Science Center, University of Tokyo, Tokyo 113, Japan
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Lin H, Zhang M, Wang F, Meng F, Liao BQ, Hong H, Chen J, Gao W. A critical review of extracellular polymeric substances (EPSs) in membrane bioreactors: Characteristics, roles in membrane fouling and control strategies. J Memb Sci 2014. [DOI: 10.1016/j.memsci.2014.02.034] [Citation(s) in RCA: 490] [Impact Index Per Article: 49.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Zhang Y, Zhang M, Wang F, Hong H, Wang A, Wang J, Weng X, Lin H. Membrane fouling in a submerged membrane bioreactor: effect of pH and its implications. BIORESOURCE TECHNOLOGY 2013; 152:7-14. [PMID: 24280082 DOI: 10.1016/j.biortech.2013.10.096] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2013] [Revised: 10/23/2013] [Accepted: 10/28/2013] [Indexed: 06/02/2023]
Abstract
The effect of pH on membrane fouling in a submerged membrane bioreactor (MBR) was investigated in this study. It was found that, pH increase slightly increased the resistance of virgin membrane and fouled membrane. Pore clogging resistance was quite low, which was not apparently affected by the pH variation. Lower pH resulted in higher adherence of sludge flocs on membrane surface. Thermodynamic analysis showed that a repulsive energy barrier existed in the process of the foulants approaching to membrane surface. This energy barrier would decrease with pH decreased, suggesting the existence of a critical pH below which the repulsive energy barrier would disappear, which would facilitate attachment of the foulants. The resistance of the formed cake layer would significantly increase with the feed pH. This result could be explained by the osmotic pressure mechanism. The obtained findings also provided important implications for membrane fouling mitigation in MBRs.
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Affiliation(s)
- Ye Zhang
- College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua 321004, PR China
| | - Meijia Zhang
- College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua 321004, PR China
| | - Fangyuan Wang
- College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua 321004, PR China
| | - Huachang Hong
- College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua 321004, PR China
| | - Aijun Wang
- College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua 321004, PR China
| | - Juan Wang
- Jinhua Institute of Environmental Science Research, Jinhua 321017, PR China
| | - Xuexiang Weng
- College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004, PR China
| | - Hongjun Lin
- College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua 321004, PR China.
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