scholarly journals Diatomite Dynamic Membrane Fouling Behaviour during Dewatering of Chlorella pyrenoidosa in Aquaculture Wastewater

Membranes ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 945
Author(s):  
Weiwei Huang ◽  
Weiguang Lv ◽  
Huaqiang Chu ◽  
Weiwei Lv ◽  
Wenzong Zhou ◽  
...  
Keyword(s):  
Membrane Fouling ◽  
Membrane Filtration ◽  
Copper Concentration ◽  
Copper Ions ◽  
Chlorella Pyrenoidosa ◽  
Dynamic Membrane ◽  
High Copper ◽  
Slime Layer ◽  
Cake Layer ◽  
Aquaculture Wastewater

Combined microalgal and membrane filtration could effectively treat aquaculture wastewater; however, the membrane fouling induced by extracellular organic matter (EOM) during the dewatering process is an issue. This study investigated diatomite dynamic membrane (DDM) fouling behaviour during the dewatering of Chlorella pyrenoidosa under the influence of copper ions. The results indicate that copper ion heavy metals in aquaculture wastewater significantly affected purification and algae dewatering by DDM. Aquaculture wastewater with a high copper concentration (1 and 0.5 mg/L) could induce serious DDM fluxes and cake layer filtration resistance (Rc), whereas fewer filtration fluxes were induced when aquaculture wastewater had a low copper concentration, particularly that of 0.1 mg/L, at which the Rc was lowest and the concentration effect was highest. Macromolecular organics of EOM, such as biopolymers, polysaccharides, and proteins, were responsible for DDM fouling and accumulated mostly in the slime layer, whereas only a small amount of them accumulated in the diatomite layer. The DDM rejected more protein-like organics of EOM in the slime layer when dewatering algae at low copper concentrations (<0.1 mg/L); however, when using the DDM to dewater algae at high copper concentrations, more polysaccharides of EOM were rejected (0.5 < Cu2+ < 5 mg/L). This result has significant ramifications for aquaculture wastewater treatment as well as algae separation and concentration by the DDM.

scholarly journals Optimization of In Situ Backwashing Frequency for Stable Operation of Anaerobic Ceramic Membrane Bioreactor

Processes ◽  
2020 ◽  
Vol 8 (5) ◽  
pp. 545 ◽  
Author(s):  
Rathmalgodage Thejani Nilusha ◽  
Tuo Wang ◽  
Hongyan Wang ◽  
Dawei Yu ◽  
Junya Zhang ◽  
...  
Keyword(s):  
Membrane Fouling ◽  
Membrane Filtration ◽  
Membrane Bioreactor ◽  
Ceramic Membrane ◽  
Pure Water ◽  
Ex Situ ◽  
Stable Operation ◽  
Chemical Cleaning ◽  
Cake Layer

The cost-effective and stable operation of an anaerobic ceramic membrane bioreactor (AnCMBR) depends on operational strategies to minimize membrane fouling. A novel strategy for backwashing, filtration and relaxation was optimized for stable operation of a side stream tubular AnCMBR treating domestic wastewater at the ambient temperature. Two in situ backwashing schemes (once a day at 60 s/day, and twice a day at 60 s × 2/day) maintaining 55 min filtration and 5 min relaxation as a constant were compared. A flux level over 70% of the initial membrane flux was stabilized by in situ permeate backwashing irrespective of its frequency. The in situ backwashing by permeate once a day was better for energy saving, stable membrane filtration and less permeate consumption. Ex situ chemical cleaning after 60 days’ operation was carried out using pure water, sodium hypochlorite (NaOCl), and citric acid as the order. The dominant cake layer was effectively reduced by in situ backwashing, and the major organic foulants were fulvic acid-like substances and humic acid-like substances. Proteobacteria, Firmucutes, Epsilonbacteria and Bacteroides were the major microbes attached to the ceramic membrane fouling layer which were effectively removed by NaOCl.

scholarly journals Application of Coagulation–Membrane Rotation to Improve Ultrafiltration Performance in Drinking Water Treatment

Membranes ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 643
Author(s):  
Hongjian Yu ◽  
Weipeng Huang ◽  
Huachen Liu ◽  
Tian Li ◽  
Nianping Chi ◽  
...  
Keyword(s):  
Shear Stress ◽  
Drinking Water ◽  
Water Treatment ◽  
Membrane Fouling ◽  
Membrane Filtration ◽  
Drinking Water Treatment ◽  
Permeate Flux ◽  
Organic Removal ◽  
Cake Layer ◽  
The Impact

The combination of conventional and advanced water treatment is now widely used in drinking water treatment. However, membrane fouling is still the main obstacle to extend its application. In this study, the impact of the combination of coagulation and ultrafiltration (UF) membrane rotation on both fouling control and organic removal of macro (sodium alginate, SA) and micro organic matters (tannic acid, TA) was studied comprehensively to evaluate its applicability in drinking water treatment. The results indicated that membrane rotation could generate shear stress and vortex, thus effectively reducing membrane fouling of both SA and TA solutions, especially for macro SA organics. With additional coagulation, the membrane fouling could be further reduced through the aggregation of mediate and macro organic substances into flocs and elimination by membrane retention. For example, with the membrane rotation speed of 60 r/min, the permeate flux increased by 90% and the organic removal by 35% in SA solution, with 40 mg/L coagulant dosage, with an additional 70% increase of flux and 5% increment of organic removal to 80% obtained. However, too much shear stress could intensify the potential of fiber breakage at the potting, destroying the flocs and resulting in the reduction of permeate flux and deterioration of effluent quality. Finally, the combination of coagulation and membrane rotation would lead to the shaking of the cake layer, which is beneficial for fouling mitigation and prolongation of membrane filtration lifetime. This study provides useful information on applying the combined process of conventional coagulation and the hydrodynamic shear force for drinking water treatment, which can be further explored in the future.

scholarly journals The Effect of Ca and Mg Ions on the Filtration Profile of Sodium Alginate Solution in a Polyethersulfone-2-(methacryloyloxy) Ethyl Phosphorylchloline Membrane

Water ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 1207 ◽  
Author(s):  
Nasrul Arahman ◽  
Suffriandy Satria ◽  
Fachrul Razi ◽  
M. Bilad
Keyword(s):  
Sodium Alginate ◽  
Relative Permeability ◽  
Hollow Fiber ◽  
Membrane Fouling ◽  
Membrane Filtration ◽  
Hollow Fiber Membrane ◽  
Pure Water ◽  
Fiber Membrane ◽  
Cake Layer ◽  
The Stability

The efforts to improve the stability of membrane filtration in applications for wastewater treatment or the purification of drinking water still dominate the research in the field of membrane technology. Various factors that cause membrane fouling have been explored to find the solution for improving the stability of the filtration and prolong membrane lifetime. The present work explains the filtration performance of a hollow fiber membrane that is fabricated from polyethersulfone-2-(methacryloyloxy) ethyl phosphorylchloline while using a sodium alginate (SA) feed solution. The filtration process is designed in a pressure driven cross-flow module using a single piece hollow fiber membrane in a flow of outside-inside We investigate the effect of Ca and Mg ions in SA solution on the relative permeability, membrane resistance, cake resistance, and cake formation on the membrane surface. Furthermore, the performance of membrane filtration is predicted while using mathematical models that were developed based on Darcy’s law. Results show that the presence of Ca ions in SA solution has the most prominent effect on the formation of a cake layer. The formed cake layer has a significant effect in lowering relative permeability. The developed models have a good fit with the experimental data for pure water filtration with R2 values between 0.9200 and 0.9999. When treating SA solutions, the developed models fit well with experimental with the best model (Model I) shows R2 of 0.9998, 0.9999, and 0.9994 for SA, SA + Ca, and SA + Mg feeds, respectively.

Modeling NOM fouling of low pressure membranes: impact of membrane properties and NOM characteristics

2008 ◽  
Vol 8 (1) ◽  
pp. 75-83
Author(s):  
NoHwa Lee ◽  
John Pellegrino ◽  
Gary Amy
Keyword(s):  
Membrane Fouling ◽  
Membrane Filtration ◽  
Principal Component ◽  
Low Pressure ◽  
Time Frame ◽  
Membrane Properties ◽  
Flux Decline ◽  
Cake Layer ◽  
Highly Correlated ◽  
Significant Flux

This research attempted to identify characteristic coordinates responsible for significant flux decline in low pressure membrane filtration, and to explain relationships among those coordinates with a modeling approach. A Pearson's correlation matrix supported that significant flux decline over a short time frame (low delivered DOC) is highly correlated with high molecular weight (MW) components of NOM. Simulations of flux decline by model equations were close to the experimental results revealing that low pressure membrane fouling is dominantly affected by NOM characteristics and membrane properties. One source water, exhibiting the highest flux decline, showed mostly cake formation as a fouling mechanism. The results indicate that significant flux decline is caused by high MW components leading to formation of a cake layer. Principal component analysis (PCA) revealed that high MW polysaccharides are the most important NOM component affecting significant membrane fouling.

The fouling characterization and control in the high concentration PAC membrane bioreactor HCPAC-MBR

2005 ◽  
Vol 51 (6-7) ◽  
pp. 77-84 ◽  
Author(s):  
G.T. Seo ◽  
S.W. Jang ◽  
S.H. Lee ◽  
C.H. Yoon
Keyword(s):  
Membrane Fouling ◽  
Membrane Filtration ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Pilot Scale ◽  
High Concentration ◽  
Nakdong River Basin ◽  
Cake Layer ◽  
Experimental Apparatus ◽  
Operation Period

This study focuses on the experimental investigation to identify the effect of PAC at high concentrations on the fouling of membranes. A pilot-scale experimental apparatus was installed at a water treatment plant located downstream of Nakdong river basin, Korea. Effluent of rapid sand filter was used as influent of the system, which consists of PAC bio-reactor, submerged membrane module (hollow fiber with pore size 0.1 μm) and air supply facility. PAC was dosed at 40 g/L initially and it was not replaced during the operation period. Suction type filtration was carried out at intervals of 12 min. suction and 3 min. idling. At the initial flux 0.36 m/d, the system could be operated stably for around 90 days at target trans-membrane pressure (TMP) of 40 kPa. Among total resistance of membrane filtration, cake and gel layer resistance, Rc+Rg, was the dominant fraction (more than 90% of the total) to increase the filtration pressure, which means that the filtration resistance could be controlled by the PAC cake layer and then irreversible membrane fouling could be prevented. Three minutes air backwashing every 3 days could extend the operation period to 127 days. Organics were analyzed in terms of molecular weight structure. The influent of the system consists of 15.0% and 74.4% of hydrophobic and hydrophilic natural organic matter (NOM), respectively. Hydrophobic and hydrophilic (electrostatic) interaction was the main factor on fouling of the membrane in the reactor. Hydrophobic fraction decreased slightly in the effluent, which means hydrophobic NOM removal in the reactor by adsorption. Organics accumulated in the membrane were extracted for analysis after a certain period of operation. The fraction of hydrophobic and hydrophilic organics was 41.4% and 38.9%, respectively. On the basis of the experimental results, the hydrophobic organics were the major materials causing the fouling of the membrane, which should be changed to other types of material.

scholarly journals A Study on Membrane Filtration Characteristics of Methanogenic Mixed Liquor in Two Phase Anaerobic Digestion of Food Waste

2020 ◽  
Vol 42 (3) ◽  
pp. 151-163
Author(s):  
Min-Ju Park ◽  
Gyu-Tae Seo
Keyword(s):  
Anaerobic Digestion ◽  
Food Waste ◽  
Membrane Fouling ◽  
Membrane Filtration ◽  
Membrane Surface ◽  
Solid Retention Time ◽  
Two Phase ◽  
Mixed Liquor ◽  
Cross Flow Filtration ◽  
Cake Layer

Objectives:An experimental study was conducted to investigate the membrane filtration characteristics of mixed liquor in methanogenic reactor to extend solid retention time (SRT) in food waste anaerobic digestion system.Methods:On the basis of the particle size distribution (0.5~700 µm) of the methanogenic mixed liquor, three grade membranes (MF, UF, NF) were tested in a stirred cell filtration and a plate type module. Furthermore foulants of membrane, especially UF, was investigated by SEM-EDS, FTIR, SEC.Results and Discussion:As a result UF membrane was selected for stable filtration of the liquor in terms of flux (2.51 L/m<sup>2</sup>･h･bar) and the flux recovery (100%) as well as filtration resistance (Total 7.15.E+13 m<sup>-1</sup>). Average flux was 18 L/m<sup>2</sup>･h･bar for the selected UF membrane in cross flow filtration using a flat plate module. The filtration results showed that membrane fouling was caused by gel and cake layer formed on the membrane surface and 90% of the initial flux could be recovered by physical washing. It was identified that major fouling causing materials were byproducts of carbohydrate and protein decomposition, and small amount of inorganic substance detected on the membrane surface were salt and struvite like materials.Conclusions:Based on the membrane filtration characteristics analyzed from the study, the UF membrane coupled anaerobic digestion is feasible to be applied as a novel food waste treatment system for SRT extension of the methanogenic reactor.

scholarly journals A Brief Review on the Resistance-in-Series Model in Membrane Bioreactors (MBRs)

Membranes ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 24 ◽  
Author(s):  
Gaetano Di Bella ◽  
Daniele Di Trapani
Keyword(s):  
Membrane Fouling ◽  
Membrane Bioreactors ◽  
Total Resistance ◽  
Correct Evaluation ◽  
Dynamic Membrane ◽  
Layer Removal ◽  
Cake Layer ◽  
In Series ◽  
Positive Effect ◽  
Fundamental Mechanism

The cake layer deposited on the membrane modules of membrane bioreactors (MBRs), especially under a submerged configuration, represents a relevant and fundamental mechanism deeply influencing the development of membrane fouling. It negatively affects the total resistance to filtration, while exerting a positive effect as a “pre-filter” promoting the “dynamic membrane” that protects the physical membrane from internal fouling. These two opposite phenomena should be properly managed, where the submerged membranes are usually subjected to a periodical cake layer removal through ordinary (permeate backwashing and air scouring) and/or irregular cleaning actions (manual physical cleaning). In this context, the physical removal of the cake layer is needed to maintain the design filtration characteristics. Nevertheless, the proper evaluation of the effect of physical cleaning operations is still contradictory and under discussion, referring in particular to the correct evaluation of fouling mechanisms. The aim of the present work was to summarize the different aspects that influence the fouling investigations, based on simple models for the evaluation of the resistance to filtration due to the cake layer, through physical cleaning operations.

scholarly journals Effect of PAC on the Behavior of Dynamic Membrane Bioreactor Filtration Layer Based on the Analysis of Mixed Liquid Properties and Model Fitting

Membranes ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 420
Author(s):  
Chunyan Huang ◽  
Hongju Liu ◽  
Shujuan Meng ◽  
Dawei Liang
Keyword(s):  
Organic Matter ◽  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Removal Rate ◽  
Constant Current ◽  
Transmembrane Pressure ◽  
Dynamic Membrane ◽  
Organic Matter Removal ◽  
Cake Layer ◽  
Dynamic Membrane Bioreactor

Recently, dynamic membrane bioreactor (DMBR) has gradually gained the interest of researchers for the development of membrane technology. In this paper, we set up parallel experiments to investigate the effect of powder activated carbon (PAC) on organic matter removal, transmembrane pressure, and filter cake layer characterization to make an overall performance assessment of DMBR. The results showed that DMBR has a good removal effect on organic matter removal, and with a chemical oxygen demand removal rate over 85%. Protein was found to be the main membrane fouling substance. Due to the electric double-layer effect, membrane fouling tended to be alleviated when the PN/PS value was low. Using a filtration model under constant current conditions, the filtration process through the cake layer was observed to be consistent with cake-intermediate model.

scholarly journals Evaluation of the importance of various operating and sludge property parameters to the fouling of membrane bioreactors

2011 ◽  
Vol 64 (6) ◽  
pp. 1340-1346 ◽  
Author(s):  
F. Y. Sun ◽  
X. Y. Li
Keyword(s):  
Membrane Fouling ◽  
Membrane Filtration ◽  
Extracellular Polymeric Substances ◽  
Membrane Surface ◽  
Cross Flow ◽  
Correlation Coefficients ◽  
Single Fibre ◽  
Cake Layer ◽  
The Cross ◽  
Filtration Flux

A single-fibre microfiltration system was employed to investigate the importance of various operating and sludge property parameters to the membrane fouling during sludge filtration. The sludge was obtained from a submerged membrane bioreactor (SMBR). A series of comparative and correlative filtration and fouling tests were conducted on the influence of the operating variables, sludge properties and the liquid-phase organic substances on the membrane fouling development. The test results were analysed statistically with Pearson's correlation coefficients and the stepwise multi-variable linear regression. According to the statistical evaluation, the membrane fouling rate has a positive correlation with the biopolymer cluster (BPC) concentration, sludge concentration (mixed liquor suspended solids, MLSS), filtration flux and viscosity, a negative correlation with the cross-flow velocity, and a weak correlation with the extracellular polymeric substances and soluble microbial products. BPC appear to be the most important factor to membrane fouling development during the sludge filtration, followed by the filtration flux and MLSS concentration. The cross-flow rate also is important to the fouling control. It is argued that, during membrane filtration of SMBR sludge, BPC interact with sludge flocs at the membrane surface to facilitate the deposition of the sludge cake layer, leading to serious membrane fouling.

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