Influence of organic and inorganic flocculants on physical–chemical properties of biomass and membrane-fouling rate

Ji, Jing; Qiu, Jiangping; Wai, Nyunt; Wong, Fook-Sin; Li, Yaozhong

doi:10.1016/j.watres.2009.11.013

Cited by 115 publications

(50 citation statements)

References 24 publications

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“…The relative hydrophobicity (RH) is the tendency of adherence of sludge flocs to hydrocarbon (n-hexane in this study) and was measured following the method by Ji et al (2010). The equation RH (%) = (1 À MLSS e /MLSS i ) Â 100% was used to calculate RH, where MLSS e is the MLSS concentration in the aqueous phase after emulsification and MLSS i is the initial MLSS concentration of the sample.…”

Section: Analysis Methodsmentioning

confidence: 99%

A comparison study on membrane fouling in a sponge-submerged membrane bioreactor and a conventional membrane bioreactor

Deng

Guo

Ngo

et al. 2014

Bioresource Technology

108

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h i g h l i g h t sLess SMP and bound EPS in activated sludge in the SSMBR induced lower R C and R P . Lower biomass growth and sludge viscosity contributed to lower R C in the SSMBR. Larger sludge flocs, higher zeta potential and RH led to lower R T in the SSMBR. Sponge could prevent pore blocking and cake layer formation. Sponge addition could reduce SMP C and EPS C through adsorption and biodegradation. This study compared membrane fouling in a sponge-submerged membrane bioreactor (SSMBR) and a conventional membrane bioreactor (CMBR) based on sludge properties when treating synthetic domestic wastewater. In the CMBR, soluble microbial products (SMP) in activated sludge were a major contributor for initial membrane fouling and presented higher concentration in membrane cake layer. Afterwards, membrane fouling was mainly governed by bound extracellular polymeric substances (EPS) in activated sludge, containing lower proteins but significantly higher polysaccharides. Sponge addition could prevent cake formation on membrane surface and pore blocking inside membrane, thereby alleviating membrane fouling. The SSMBR exhibited not only less growth of the biomass and filamentous bacteria, but also lower cake layer and pore blocking resistance due to lower bound EPS concentrations in activated sludge. Less membrane fouling in SSMBR were also attributed to larger particle size, higher zeta potential and relative hydrophobicity of sludge flocs.

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Section: Analysis Methodsmentioning

confidence: 99%

A comparison study on membrane fouling in a sponge-submerged membrane bioreactor and a conventional membrane bioreactor

Deng

Guo

Ngo

et al. 2014

Bioresource Technology

108

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“…The zeta potential of mixed liquor was analyzed with a zeta potential meter (Zetasizer Nano ZS, Malvern Instruments, UK). The method reported by Deng et al [23] and Ji et al [17] was applied to determine the relative hydrophobicity (RH) of sludge flocs. Particle size distribution of sludge flocs was determined by analyzing the images obtained by the Olympus System Microscope Model BX41 (Olympus, Japan) with Image-Pro Plus software.…”

Section: Analysis Methodsmentioning

confidence: 99%

Membrane fouling reduction and improvement of sludge characteristics by bioflocculant addition in submerged membrane bioreactor

Deng

Guo

Ngo

et al. 2015

Separation and Purification Technology

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a b s t r a c tThe effectiveness of a green bioflocculant (Gemfloc Ò ) on enhanced performance of a submerged membrane bioreactor (SMBR) was evaluated in terms of membrane fouling reduction and sludge characterization. Two MBRs were operated parallelly in this study, namely conventional MBR (CMBR) and MBR with Gemfloc Ò addition (MBR-G). Results showed mitigated membrane fouling through Gemfloc Ò addition in terms of cake layer formation and pore blocking. When compared to the CMBR, in spite of more extracellular polymeric substances (EPS) presented in activated sludge, the MBR-G demonstrated less soluble microbial products (SMP), larger sludge flocs, higher zeta potential and greater relative hydrophobicity of sludge flocs, which decreased cake layer resistance and pore blocking resistance. The reduced cake layer resistance in the MBR-G could be also ascribed to less growth of suspended biomass, lower sludge viscosity, as well as less EPS, SMP and biopolymer clusters in the cake layer. In addition, a modified resistance-in-series model was employed by considering SMP and mixed liquor suspended solids. The simulated results implied that the model could predict the influence of sludge characteristics on membrane fouling behavior of the SMBR.

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“…The anti-fouling effect of organic flocculants such as polyacrylamide (PAM) and chitosan was also studied. At the dosages of£20 mg$L -1 and£150 mg$L -1 for PAM and chitosan respectively, membrane fouling was significantly alleviated, as a concomitant of increased floc size and decreased SMP concentration [84].…”

Section: Mixed Liquor Conditioningmentioning

confidence: 99%

“…Both of the properties could be qualitatively determined via column chromatography method based on differential adsorption and elution [81][82], yielding hydrophilic/hydrophobic fractions and acid/base/ neutral fractions. Another useful method for determining hydrophobicity is the bacterial adherence to hydrocarbons (BATH) test based on the partition of the target (bacteria) between aqueous phase and hydrocarbon droplet surface [83]; this method has recently been applied to the case of sludge flocs with the result termed relative hydrophobicity (RH) [84]. Additionally, surface charge could be otherwise quantified as zeta potential [84,85], though sensitive to the ionic condition applied in the measurement [86].…”

Section: Membrane Foulingmentioning

confidence: 99%

“…Another useful method for determining hydrophobicity is the bacterial adherence to hydrocarbons (BATH) test based on the partition of the target (bacteria) between aqueous phase and hydrocarbon droplet surface [83]; this method has recently been applied to the case of sludge flocs with the result termed relative hydrophobicity (RH) [84]. Additionally, surface charge could be otherwise quantified as zeta potential [84,85], though sensitive to the ionic condition applied in the measurement [86]. As for the steric properties of foulant, most attention has been focused on foulant size (or molecular weight at the macromolecular level) [82,87,88], with which the major fouling mechanism may vary substantially, as will be discussed later.…”

Section: Membrane Foulingmentioning

confidence: 99%

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Recent advances in membrane bioreactor technology for wastewater treatment in China

Huang

Xiao

Shen

2010

Front. Environ. Sci. Eng. China

109

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Since the introduction of the membrane bioreactor (MBR) in China in the early 1990s, remarkable progress has been achieved on the research and application of this technology. China has now become one of the most active fields in the world in this regard. This review outlines the development of MBR-based processes in China and their performance of treating municipal and industrial wastewaters. Since membrane fouling is a critical operational problem with MBR processes, this paper also proposes updated understanding of fouling mechanisms and strategies of fouling control, which are mainly compiled from publications of Chinese researchers. As for the commercial application of MBR in the country, the latest statistics of large-scale MBR plants ( > 10000 m 3 $d -1 ) are provided, and the growth trend of total treatment capacity as well as its driving force is analyzed.

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Influence of organic and inorganic flocculants on physical–chemical properties of biomass and membrane-fouling rate

Cited by 115 publications

References 24 publications

A comparison study on membrane fouling in a sponge-submerged membrane bioreactor and a conventional membrane bioreactor

A comparison study on membrane fouling in a sponge-submerged membrane bioreactor and a conventional membrane bioreactor

Membrane fouling reduction and improvement of sludge characteristics by bioflocculant addition in submerged membrane bioreactor

Recent advances in membrane bioreactor technology for wastewater treatment in China

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