scholarly journals Optimization of Air Backwash Frequency during the Ultrafiltration of Seawater

Membranes ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 78
Author(s):  
Clemence Cordier ◽  
Tarik Eljaddi ◽  
Nadjim Ibouroihim ◽  
Christophe Stavrakakis ◽  
Patrick Sauvade ◽  
...  
Keyword(s):  
Membrane Fouling ◽  
Membrane Module ◽  
Industrial Scale ◽  
Membrane Performance ◽  
Operation Conditions ◽  
Dead End ◽  
Variation Versus ◽  
In Series ◽  
Seawater Quality

The main objective of this paper is to study the effect of new air backwash on dead-end ultrafiltration of seawater with a pilot at semi-industrial scale (20 m3/day). To control membrane fouling, two different backwashes were used to clean the membrane: classical backwash (CB) and new air backwash (AB) that consists of injecting air into the membrane module before a classical backwash. To evaluate the efficiency of AB and CB, a resistance in series model was used to calculate each resistance: membrane (Rm), reversible (Rrev) and irreversible (Rirr). The variation of the seawater quality was considered by integrating the turbidity variation versus time. The results indicate clearly that AB was more performant than CB and frequency of AB/CB cycles was important to control membrane fouling. In this study, frequencies of 1/5 and 1/3 appear more efficient than 1/7 and 1/9. In addition, the operation conditions (flux and time of filtration) had an important role in maintaining membrane performance—whatever the variation of the seawater quality.

Filtration of biological suspension: membrane performance

2005 ◽  
Vol 5 (3-4) ◽  
pp. 227-232
Author(s):  
S. Delgado ◽  
F. Díaz ◽  
R. Villarroel ◽  
M.D. García ◽  
L. Vera ◽  
...  
Keyword(s):  
Membrane Fouling ◽  
Wastewater Reuse ◽  
Process Efficiency ◽  
Government Regulations ◽  
Quality Requirements ◽  
Membrane Performance ◽  
Several Variables ◽  
Dead End ◽  
Appropriate Treatment ◽  
Treatment Technologies

Wastewater reuse provides a substantial non-conventional water resource, mainly for agriculture. However, it requires appropriate treatment technologies and previous evaluation so as to meet quality requirements imposed by government regulations and crop needs. Among all the technologies applied to wastewater treatment, membrane-based systems have gained increasing importance, although their main drawback is progressive membrane fouling, which affects process efficiency enormously. The present study analyses the filterability of some biological suspensions as well as the influence of several variables in membrane fouling. Classic dead–end filtration models are used in an attempt to better understand fouling mechanisms and develop methods to prevent or retard it.

Evaluation of innovative operation concept for flat sheet MBR filtration system

2008 ◽  
Vol 57 (4) ◽  
pp. 613-620 ◽  
Author(s):  
L. Weinrich ◽  
A. Grélot
Keyword(s):  
Membrane Fouling ◽  
Industrial Wastewater ◽  
Limiting Factors ◽  
Water Solutions ◽  
Membrane Performance ◽  
Operation Conditions ◽  
Flat Sheet ◽  
Filtration System ◽  
Net Flux ◽  
The Impact

One of the most limiting factors for the extension and acceptance of MBR filtration systems for municipal and industrial wastewater is the impact of membrane fouling on maintenance, operation and cleaning efforts. One field of action in the European Research Project “AMEDEUS” is the development and testing of MBR module concepts with innovative fouling-prevention technology from three European module manufacturers. This article deals with the performances of the flat-sheet modules by A3 Water Solutions GmbH in double-deck configuration evaluated over 10 months in Anjou Recherche under typical biological operation conditions for MBR systems (MLSS = 10 g/l; SRT = 25 days). By using a double-deck configuration, it is possible to operate with a net flux of 25.5 l/m2.h at 20°C, a membrane air flow rate of 0.21 Nm3/h.m2 of membrane to achieve a stable permeability of around 500–600 l/m2.h.bar. Additionally, it was observed that it is possible to recover the membrane performance after biofouling during operation without intensive cleaning and to maintain stable permeability during peak flows.The evaluated concepts for equipping and operating MBR systems will be applied to several full-scale plants constructed by A3 Water Solutions GmbH.

Modification of ASM No.1 for a submerged membrane bioreactor system: including the effects of soluble microbial products on membrane fouling

2003 ◽  
Vol 47 (12) ◽  
pp. 177-181 ◽  
Author(s):  
J. Cho ◽  
K.-H. Ahn ◽  
Y. Seo ◽  
Y. Lee
Keyword(s):  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Membrane Resistance ◽  
Soluble Microbial Products ◽  
Submerged Membrane Bioreactor ◽  
Operation Conditions ◽  
In Series ◽  
Bioreactor System ◽  
Microbial Products ◽  
Major Factors

In this study, a mathematical model for the submerged membrane bioreactor (SMBR) was developed by combining the activated sludge model (ASM) with a membrane resistance-in-series model. Some modifications were introduced to make ASM to be suitable for describing the characteristics of SMBR. A set of the 1st-order differential equations was established for 13 dependent variables relevant to particles and soluble matters. Performing model simulations for various conditions, the time when a membrane would be fouled could be predicted as well as the effluent quality. From simulation results, F/M ratio and SRT can be considered as major factors of the soluble microbial products (SMP) concentration in a reactor and it is clear that SMP can play an important role in membrane fouling and water quality simultaneously. The model would be very helpful in optimizing operation conditions as well as in designing an optimal SMBR system.

scholarly journals Potential Pitfalls in Membrane Fouling Evaluation: Merits of Data Representation as Resistance Instead of Flux Decline in Membrane Filtration

Membranes ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 460
Author(s):  
Bastiaan Blankert ◽  
Bart Van der Bruggen ◽  
Amy E. Childress ◽  
Noreddine Ghaffour ◽  
Johannes S. Vrouwenvelder
Keyword(s):  
Membrane Fouling ◽  
Membrane Filtration ◽  
Data Representation ◽  
Strong Impact ◽  
Experimental Conditions ◽  
Permeable Membrane ◽  
Dead End ◽  
Flux Decline ◽  
The Difference ◽  
Filtration Flux

The manner in which membrane-fouling experiments are conducted and how fouling performance data are represented have a strong impact on both how the data are interpreted and on the conclusions that may be drawn. We provide a couple of examples to prove that it is possible to obtain misleading conclusions from commonly used representations of fouling data. Although the illustrative example revolves around dead-end ultrafiltration, the underlying principles are applicable to a wider range of membrane processes. When choosing the experimental conditions and how to represent fouling data, there are three main factors that should be considered: (I) the foulant mass is principally related to the filtered volume; (II) the filtration flux can exacerbate fouling effects (e.g., concentration polarization and cake compression); and (III) the practice of normalization, as in dividing by an initial value, disregards the difference in driving force and divides the fouling effect by different numbers. Thus, a bias may occur that favors the experimental condition with the lower filtration flux and the less-permeable membrane. It is recommended to: (I) avoid relative fouling performance indicators, such as relative flux decline (J/J0); (II) use resistance vs. specific volume; and (III) use flux-controlled experiments for fouling performance evaluation.

scholarly journals Membrane Fouling Controlled by Adjustment of Biological Treatment Parameters in Step-Aerating MBR

Membranes ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 553
Author(s):  
Dimitra C. Banti ◽  
Manassis Mitrakas ◽  
Petros Samaras
Keyword(s):  
Membrane Fouling ◽  
Membrane Filtration ◽  
Municipal Wastewater ◽  
Operating Conditions ◽  
Transmembrane Pressure ◽  
Aeration Tank ◽  
Filamentous Bacteria ◽  
Membrane Performance ◽  
Low Concentrations ◽  
Fouling Reduction

A promising solution for membrane fouling reduction in membrane bioreactors (MBRs) could be the adjustment of operating parameters of the MBR, such as hydraulic retention time (HRT), food/microorganisms (F/M) loading and dissolved oxygen (DO) concentration, aiming to modify the sludge morphology to the direction of improvement of the membrane filtration. In this work, these parameters were investigated in a step-aerating pilot MBR that treated municipal wastewater, in order to control the filamentous population. When F/M loading in the first aeration tank (AT1) was ≤0.65 ± 0.2 g COD/g MLSS/d at 20 ± 3 °C, DO = 2.5 ± 0.1 mg/L and HRT = 1.6 h, the filamentous bacteria were controlled effectively at a moderate filament index of 1.5–3. The moderate population of filamentous bacteria improved the membrane performance, leading to low transmembrane pressure (TMP) at values ≤2 kPa for a great period, while at the control MBR the TMP gradually increased reaching 14 kPa. Soluble microbial products (SMP), were also maintained at low concentrations, contributing additionally to the reduction of ΤΜP. Finally, the step-aerating MBR process and the selected imposed operating conditions of HRT, F/M and DO improved the MBR performance in terms of fouling control, facilitating its future wider application.

Insight into the membrane fouling in a pilot SWNF system with different membrane module arrangements

Desalination ◽  
2022 ◽  
Vol 521 ◽  
pp. 115285
Author(s):  
Lin Tong ◽  
Huiyu Gao ◽  
Shougang Fan ◽  
Caini Liu ◽  
Jianyou Wang ◽  
...  
Keyword(s):  
Membrane Fouling ◽  
Membrane Module ◽  
Insight Into
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