The Performance and Fouling Control of Submerged Hollow Fiber (HF) Systems: A Review

Akhondi, Ebrahim; Zamani, Farhad; Tng, Keng Han; Leslie, Greg; Krantz, William B.; Fane, Anthony G.; Chew, Jia Wei

doi:10.3390/app7080765

Cited by 60 publications

(37 citation statements)

References 329 publications

(483 reference statements)

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“…The submerged modules concept is well established for the filtration of solutions containing a substantial quantity of suspended solids. The low values of TMP (usually below 0.05 MPa) limit fouling through the achievement of operating conditions close to the critical flux [4,5]. With regard to this, the submerged modules are employed in the membrane bioreactors (MBR) [6][7][8].…”

Section: Introductionmentioning

confidence: 99%

“…Air bubbling induces the fibre movement and the flow of feed along the membranes, which generates the surface shear, mitigating the deposition of a fouling layer [1,7]. Moreover, a periodic backwashing and additional chemical cleaning is employed for the removal of deposits from the membrane surface, thus enabling its long-term exploitation [4,[7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

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The Application of Submerged Modules for Membrane Distillation

Gryta

2020

Membranes

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This paper deals with the efficiency of capillary modules without an external housing, which were used as submerged modules in the membrane distillation process. The commercial hydrophobic capillary membranes fabricated for the microfiltration process were applied. Several constructional variants of submerged modules were discussed. The influence of membrane arrangement, packing density, capillary diameter and length on the module performance was determined. The effect of process conditions, i.e., velocity and temperature of the streams, on the permeate flux was also evaluated. The submerged modules were located in the feed tank or in the distillate tank. It was found that much higher values of the permeate flux were obtained when the membranes were immersed in the feed with the distillate flowing inside the capillary membranes. The efficiency of submerged modules was additionally compared with the conventional membrane distillation (MD) capillary modules and a similar performance of both constructions was achieved.Membranes 2020, 10, 25 2 of 21 the module channels. With regard to this, in order to achieve a higher degree of water recovery, the feed is circulated in the closed loop and simultaneously reheated before the feed water enters the module [11,12]. These operations are omitted by immersing the capillary membranes inside the feed tank. Thus, the application of submerged modules significantly simplifies a construction of installation, which also additionally reduces the heat losses in the MD process [13][14][15].During a long-term exploitation of the MD module, the water fills a fraction of the membrane pores, thereby the elimination of membrane wettability becomes a very important issue [16][17][18]. The MD process is not pressure-driven, however, the hydrostatic pressure is necessary in order to obtain the feed flow through the module channels. Although the value of this pressure is usually not high, this is one of the reasons accelerating the membrane wetting, especially if the surface tension of the feed solution is low [17,18]. The immersion of membranes inside a non-pressure feed vessel allows elimination of a hydrostatic pressure generated by feed pumping.Fouling is also one of the reasons causing the membrane wetting [19][20][21]. The application of air bubbling is commonly employed in the MBR in order to mitigate the fouling phenomenon and it also proves to be effective in the MD process [15,22,23]. Moreover, in the case of the presence of surface active agents, they are accumulated on the surface of air bubbles, which additionally limits the influence of these substances on the pore wetting [23]. Such a concept was successfully used in the MD process applied to the treatment of wastewater from the petrochemical industry and to the treatment of produced water generated during the extraction of gas and petroleum [2,24].The driving force in the MD process does not directly depend on the bulk feed temperature, but on the feed/membrane interfacial temperature [25][26][27][28][29][30][31]. Therefore, t...

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The Application of Submerged Modules for Membrane Distillation

Gryta

2020

Membranes

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“…These membranes exhibit high transport characteristics: the water flux achieves 2 m 3 /(m 2 h bar) [2], while the nitrogen gas permeability is 120 m 3 /(m 2 h bar) [24]. Polyacrylonitrile hollow fiber membranes are intensively used in ultra- [25] and nanofiltration processes [5,26] and in hydrophilic pervaporation [27].…”

Section: Introductionmentioning

confidence: 99%

Ultrafiltration Membranes Based on Various Acrylonitrile Copolymers

Matveev

Plisko

Волков

et al. 2019

Membr. Membr. Technol.

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The structure and properties of ultrafiltration membranes synthesized from bicomponent solutions in N,N-dimethylformamide using five commercial acrylonitrile copolymers of various compositions and molecular masses have been studied. The molecular mass characteristics of the copolymers (M w , M w /M n) have been determined; the viscosity properties of dilute and concentrated solutions have been studied. It has been shown that depending on the chemical composition and molecular mass of the copolymer, the concentration dependence of the water flux is different: for copolymers with a molecular mass of M w of 76000-81000 g/mol, with an increase in the copolymer concentration in solution from 12 to 16%, the water flux of the membranes decreases from 300-500 to 40-150 L/(m 2 h) depending on the copolymer composition. For samples with a higher molecular mass (M w = 99 000 and 107000 g/mol), the water flux of the membranes hardly depends on the copolymer concentration in the casting solution; it is 150 and 75 L/(m 2 h), respectively. The rejection factor of the membranes with a molecular mass of 40000 g/mol for polyvinylpyrrolidone increases with increasing copolymer concentration in the casting solution regardless of the chemical composition and molecular mass of the copolymer. Scanning electron microscopy studies of the membrane structure have shown that membranes synthesized from copolymers with a higher molecular mass have a denser structure and a thicker selective layer than the respective parameters of membranes synthesized from acrylonitrile copolymers with a lower molecular mass, which are characterized by the presence of large macrovoids in the membrane matrix. These differences in the membrane structure are attributed to different viscosities of the casting solutions at identical copolymer concentrations.

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“…Membrane fouling in membrane bioreactors (MBRs) decreases permeate yield (flux) and increases energy consumption [1,2]. Flux can be affected by concentration polarization, and external and internal membrane deposits [3]. Membrane fouling can be biological, organic and inorganic as the result of biological and chemical properties of membrane foulants [1,2].…”

Section: Introductionmentioning

confidence: 99%

Membrane Fouling Monitoring in a Submerged Membrane Bioreactor

et al. 2018

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Use of Membrane Bioreactor (MBR) technology for municipal wastewater treatment has been increased in recent years, as it successfully overcomes the disadvantages of the conventional activated sludge process. Membrane fouling is the major disadvantage of MBRs and leads to decreased membrane performance and expanded operational expenses. In this study, fouling was monitored in a pilot-scale submerged MBR system fed with municipal wastewater. TMP was directly measured on the membrane module during the operation. To control TMP increase owing to biosolids accumulation on membrane surface, successive backwashes and air-cross flow velocity increase were applied. These measures lowered TMP and improved flux.

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The Performance and Fouling Control of Submerged Hollow Fiber (HF) Systems: A Review

Cited by 60 publications

References 329 publications

The Application of Submerged Modules for Membrane Distillation

The Application of Submerged Modules for Membrane Distillation

Ultrafiltration Membranes Based on Various Acrylonitrile Copolymers

Membrane Fouling Monitoring in a Submerged Membrane Bioreactor

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