Optimization of gravity-driven membrane (GDM) filtration process for seawater pretreatment

Wu, Bing; Hochstrasser, Florian; Akhondi, Ebrahim; Ambauen, Noëmi; Tschirren, Lukas; Burkhardt, Michael; Fane, Anthony G.; Pronk, Wouter

doi:10.1016/j.watres.2016.02.021

Cited by 81 publications

(27 citation statements)

References 24 publications

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“…3d), which is different from some previous GDM system studies, where heterogeneous structures of biofilm layers were observed by CLSM scanning and maybe on account of the destructive operation in sample preparation as well as the inoculation and predation of eukaryotes [10,13]. A recent research in diverse membrane modules applied in GDM filtration cells also supported the uniform fouling architecture formed in the final stable stage [37], providing an explanation of the stable flux during this phase. In addition, it is noticed that the thickness of fouling decreased slightly and gradually during this stage.…”

Section: Fouling Investigation Using Octmentioning

confidence: 55%

Gravity-driven membrane system for secondary wastewater effluent treatment: Filtration performance and fouling characterization

Wang

Fortunato

Jeong

et al. 2017

Separation and Purification Technology

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Gravity-driven membrane (GDM) filtration is one of the promising membrane bioreactor (MBR) configurations. It operates at an ultra-low pressure by gravity, requiring a minimal energy. The objective of this study was to understand the performance of GDM filtration system and characterize the biofouling formation on a flat sheet membrane. This submerged GDM reactor was operated at constant gravitational pressure in treating of two different concentrations of secondary wastewater effluent. Morphology of biofilm layer was acquired by an in-situ and on-line optical coherence tomography (OCT) scanning in a fixed position at regular intervals. The thickness and roughness calculated from OCT images were related to the variation of flux, fouling resistance and permeate quality. At the end of experiment, fouling was quantified by total organic carbon (TOC) and adenosine tri-phosphate (ATP) method. Confocal laser scanning microscopy (CLSM) was also applied for biofouling morphology observation. The biofouling formed on membrane surface was mostly removed by physical cleaning 2 confirmed by contact angle measurement before and after cleaning. This demonstrated that fouling on the membrane under ultra-low pressure operation was highly reversible. The superiority and sustainability of GDM in both flux maintaining and long-term operation with production of high quality effluent was demonstrated.

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Section: Fouling Investigation Using Octmentioning

confidence: 55%

Gravity-driven membrane system for secondary wastewater effluent treatment: Filtration performance and fouling characterization

Wang

Fortunato

Jeong

et al. 2017

Separation and Purification Technology

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“…These reveal that DOC (especially the organics containing unsaturated bonds or aromatic chromophores) of rainwater was not removed well in GDM process. Similarly, Wu et al (2016) also found that GDM did not retain humics and low molecular weight neutrals during sea water treatment.…”

Section: Organics Removalmentioning

confidence: 85%

A low pressure gravity-driven membrane filtration (GDM) system for rainwater recycling: Flux stabilization and removal performance

et al. 2017

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Rainwater is a nature resource, which can be widely used for non-potable and potable applications in water scared countries after appropriate treatment. Gravity-driven membrane filtration (GDM) process is a promising technology for decentralized rainwater treatment due to no backwashing, flushing and chemical cleaning. In this study, we established a single lab-scale GDM system for the stored rainwater (simulative cellar rainwater) treatment with two months operation, and a stored tap water was used as a compared system to evaluate the permeability and organics removal performance. Results showed that GDM exhibited a good performance for bacteria and turbidity removals, but the removal performance of DOC was undesirable due to the low rejection of low molecular-weight fulvic. Additionally, the permeate flux reached stable with the value of 6-6.5 L/mh during 60 days operation in the rainwater system, however, the tap water system stabilized only at 4 L/mh. Hydraulically reversible resistance accounted for large proportions (90%) of the total resistance, which indicated that the flux could be recovered by simple physical flushing. The bio-fouling layer adhered on the membrane surface was characterized at the end of the filtration experiment. Higher bio-activity with lower EPS (polysaccharides and proteins) contents of the fouling layer were found in the rainwater system compared with the control system, which was the main reason for the higher flux. These results show that rainwater can be treated in a single GDM process with low maintenance, which makes the process suitable for decentralized water supply.

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“…In particular, RO systems with submerged membrane pretreatment have been proven to exhibit a consistently lower silt-density index (SDI) relative to conventional pretreatment [7,40,41,54,55]. Gravity-driven membrane filtration, which was initially developed as a low-energy process for surface water and diluted wastewater treatment, has also shown potential for seawater pretreatment that requires less energy and no chemical cleaning [56,57].…”

Section: Pretreatment For Ro Desalination and Reclamationmentioning

confidence: 99%

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

et al. 2017

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Abstract:The submerged membrane filtration concept is well-established for low-pressure microfiltration (MF) and ultrafiltration (UF) applications in the water industry, and has become a mainstream technology for surface-water treatment, pretreatment prior to reverse osmosis (RO), and membrane bioreactors (MBRs). Compared to submerged flat sheet (FS) membranes, submerged hollow fiber (HF) membranes are more common due to their advantages of higher packing density, the ability to induce movement by mechanisms such as bubbling, and the feasibility of backwashing. In view of the importance of submerged HF processes, this review aims to provide a comprehensive landscape of the current state-of-the-art systems, to serve as a guide for further improvements in submerged HF membranes and their applications. The topics covered include recent developments in submerged hollow fiber membrane systems, the challenges and developments in fouling-control methods, and treatment protocols for membrane permeability recovery. The highlighted research opportunities include optimizing the various means to manipulate the hydrodynamics for fouling mitigation, developing online monitoring devices, and extending the submerged HF concept beyond filtration.

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Optimization of gravity-driven membrane (GDM) filtration process for seawater pretreatment

Cited by 81 publications

References 24 publications

Gravity-driven membrane system for secondary wastewater effluent treatment: Filtration performance and fouling characterization

Gravity-driven membrane system for secondary wastewater effluent treatment: Filtration performance and fouling characterization

A low pressure gravity-driven membrane filtration (GDM) system for rainwater recycling: Flux stabilization and removal performance

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

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