scholarly journals Chemical Enhancement for Retrofitting Moving Bed Biofilm and Integrated Fixed Film Activated Sludge Systems into Membrane Bioreactors

Membranes ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 135
Author(s):  
Zakhar Maletskyi ◽  
Dawit K. Zigta ◽  
Olga Kulesha ◽  
Harsha Ratnaweera
Keyword(s):  
Membrane Fouling ◽  
Membrane Separation ◽  
Membrane Surface ◽  
Membrane Bioreactors ◽  
Aluminium Sulphate ◽  
Basic Principles ◽  
Chemical Enhancer ◽  
Positive Effects ◽  
Chemical Enhancement

Positive effects of retrofitting MBBR and IFAS systems into MBRs can be exploited by introducing chemical enhancement applying coagulants in the membrane separation step. The current study reports basic principles of chemical enhancement with aluminium sulphate coagulant in biofilm-MBR (Bf-MBR) based on results of total recycle tests performed at different dosages of the chemical enhancer and properties characterization of filtrates, supernatants and sediments. It demonstrates a possibility to achieve lower membrane fouling rates with dosing of aluminium sulphate coagulant into MBBR and IFAS mixed liquors by extending operational cycles by 20 and 80 time respectively as well as increasing operating permeability of membrane separation by 1.3 times for IFAS. It has been found that charge neutralization is the dominating mechanism of aluminium sulphate action as a chemical enhancer in Bf-MBR, however, properties of the membrane surface influencing charge repulsion of foulants should be considered together with the secondary ability of the coagulant to improve consolidation of sediments.

A Wall Film Model for Membrane Fouling

2018 ◽  
Author(s):  
Sina Jahangiri Mamouri ◽  
Volodymyr V. Tarabara ◽  
André Bénard
Keyword(s):  
Multiphase Flow ◽  
Membrane Fouling ◽  
Oil And Gas ◽  
Membrane Separation ◽  
Film Formation ◽  
Membrane Surface ◽  
Permeate Flux ◽  
Water Separation ◽  
Wall Film ◽  
Oil Water

Deoiling of produced or impaired waters associated with oil and gas production represents a significant challenge for many companies. Centrifugation, air flotation, and hydrocyclone separation are the current methods of oil removal from produced water [1], however the efficiency of these methods decreases dramatically for droplets smaller than approximately 15–20 μm. More effective separation of oil-water mixtures into water and oil phases has the potential to both decrease the environmental footprint of the oil and gas industry and improve human well-being in regions such as the Gulf of Mexico. New membrane separation processes and design of systems with advanced flow management offer tremendous potential for improving oil-water separation efficacy. However, fouling is a major challenge in membrane separation [2]. In this study, the behavior of oil droplets and their interaction with crossflow filtration (CFF) membranes (including membrane fouling) is studied using computational fluid dynamics (CFD) simulations. A model for film formation on a membrane surface is proposed for the first time to simulate film formation on membrane surfaces. The bulk multiphase flow is modeled using an Eulerian-Eulerian multiphase flow model. A wall film is developed from mass and momentum balances [3] and implemented to model droplet deposition and membrane surface blockage. The model is used to predict film formation and subsequent membrane fouling, and allow to estimate the actual permeate flux. The results are validated using available experimental data.

Comparison of four types of membrane bioreactor systems in terms of shear stress over the membrane surface using computational fluid dynamics

2013 ◽  
Vol 68 (12) ◽  
pp. 2534-2544 ◽  
Author(s):  
N. Ratkovich ◽  
T. R. Bentzen
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Membrane Fouling ◽  
Two Phase Flow ◽  
Membrane Surface ◽  
Cross Flow ◽  
Membrane Bioreactors ◽  
Phase Flow ◽  
Two Phase ◽  
Computational Fluid Dynamics Cfd

Membrane bioreactors (MBRs) have been used successfully in biological wastewater treatment to solve the perennial problem of effective solids–liquid separation. A common problem with MBR systems is clogging of the modules and fouling of the membrane, resulting in frequent cleaning and replacement, which makes the system less appealing for full-scale applications. It has been widely demonstrated that the filtration performances in MBRs can be greatly improved with a two-phase flow (sludge–air) or higher liquid cross-flow velocities. However, the optimization process of these systems is complex and requires knowledge of the membrane fouling, hydrodynamics and biokinetics. Modern tools such as computational fluid dynamics (CFD) can be used to diagnose and understand the two-phase flow in an MBR. Four cases of different MBR configurations are presented in this work, using CFD as a tool to develop and optimize these systems.

scholarly journals Design of a Novel Membrane Draft Tube Jet Loop Reactor (MDJLR) and Treatment of Slaughterhouse Wastewater

Membranes ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 155
Author(s):  
Burhanettin Farizoğlu ◽  
Süleyman Uzuner
Keyword(s):  
Membrane Fouling ◽  
High Efficiency ◽  
Draft Tube ◽  
Membrane Surface ◽  
Membrane Bioreactors ◽  
Operating Conditions ◽  
Membrane Module ◽  
Circulation Rate ◽  
Slaughterhouse Wastewater ◽  
Loop Reactor

The most important obstacle to the widespread use of membrane bioreactors (MBRs) is membrane fouling. In this study, a high-efficiency compact MBR was developed. Therefore, the draft tube of the jet loop reactor (JLB) was planned for use as a membrane module. The high-velocity jet streams, which are present according to the nature of the JLBs, provide high crossflow (cut-off force) on the membrane surface. Thus, the produced membrane module is operated in submerged membrane mode. This enhanced JLB modification is named the membrane draft tube jet loop reactor (MDJLR). This new system has a KLa value of 139 h−1 (at E/V of 2.24 kW m−3). In the next stage, treatment of slaughterhouse wastewater with the MDJLR was carried out. Under the 5.5 kg COD m−3 d−1 loading rate, efficiencies over 97% were achieved. The system operated continuously for 50 days without membrane backwashing or cleaning. During this period, fluxes of 3 L m−2·h−1 were approximately obtained at operating conditions of 850 mg L−1 MLSS (mixed liquor suspended solids) concentration, 1 bar suction pressure (∆P), and 3000 L h−1 circulation rate. This developed MDJLR will make jet loop membrane bioreactors (JLMBRs) and MBRs more compact and improve their performance.

Effects of mixed liquor pH on membrane fouling and micro-pollutant removals in membrane bioreactors for municipal landfill leachate treatment

2015 ◽  
Vol 72 (5) ◽  
pp. 770-778 ◽  
Author(s):  
Samunya Sanguanpak ◽  
Chart Chiemchaisri ◽  
Wilai Chiemchaisri ◽  
Kazuo Yamamoto
Keyword(s):  
Landfill Leachate ◽  
Membrane Fouling ◽  
Membrane Surface ◽  
Membrane Bioreactors ◽  
Leachate Treatment ◽  
Mixed Liquor ◽  
Municipal Landfill ◽  
Inorganic Substances ◽  
Ph Level ◽  
Ph Variations

This research investigated the membrane fouling and micro-pollutant removals in treatment of municipal landfill leachate at various pH levels (i.e. 5.5, 6.5, 7.5, and 8.5) using membrane bioreactors. The findings revealed that membrane fouling was influenced by the pH level of mixed liquor, with pH 5.5 exhibiting the most severe membrane fouling. At pH 5.5, proteins and carbohydrates were predominant in the membrane foulants, while at pH 8.5 humic-like and inorganic substances constituted the largest proportion of the foulants on the membrane surface. The removal efficiencies of micro-pollutants (bisphenol-A; 2,6-di-tert-butylphenol and 2,6-di-tert-butyl-4-methylbutylphenol) were nevertheless insignificantly influenced by the pH levels of mixed liquor. In addition, the removal rates of the compounds at pH 5.5 were slightly lower vis-à-vis at the higher pH levels. The micro-pollutant retention on the fouled membranes was also significant and highest under the mixed liquor pH of 8.5. Furthermore, the experiments demonstrated that the varying degrees of rejection by the fouled membranes could be attributed to the alteration of foulant characteristics as a result of the pH variations.

scholarly journals A novel In-situ Enzymatic Cleaning Method for Reducing Membrane Fouling in Membrane Bioreactors (MBRs)

2016 ◽  
Vol 1 (1) ◽  
pp. 1 ◽  
Author(s):  
M. R. Bilad ◽  
M. Baten ◽  
A. Pollet ◽  
C. Courtin ◽  
J. Wouters ◽  
...  
Keyword(s):  
Membrane Fouling ◽  
High Performance ◽  
Membrane Filtration ◽  
Membrane Surface ◽  
Anion Exchange Chromatography ◽  
Magnetic Activity ◽  
Exchange Chromatography ◽  
Membrane Bioreactors ◽  
Cleaning Method

A novel in-situ enzymatic cleaning method was developed for fouling control in membrane bioreactors (MBRs). It is achieved by bringing the required enzymes near the membrane surface by pulling the enzymes to a magnetic membrane (MM) surface by means of magnetic forces, exactly where the cleaning is required. To achieve this, the enzyme was coupled to a magnetic nanoparticle (MNP) and the membrane it self was loaded with MNP. The magnetic activity was turned by means of an external permanent magnet. The effectiveness of concept was tested in a submerged membrane filtration using the model enzyme-substrate of Bacillus subitilis xylanase-arabinoxylan. The MM had almost similar properties compared to the unloaded ones, except for its well distributed MNPs. The enzyme was stable during coupling conditions and the presence of coupling could be detected using a high-performance anion-exchange chromatography (HPAEC) analysis and Fourier transform infrared spectroscopy (FTIR). The system facilitated an in-situ enzymatic cleaning and could be effectively applied for control fouling in membrane bioreactors (MBRs).

scholarly journals Fouling-resistant biofilter of an anaerobic electrochemical membrane reactor

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Qilin Yu ◽  
Yaobin Zhang
Keyword(s):  
Membrane Fouling ◽  
Membrane Reactor ◽  
Dynamic Equilibrium ◽  
Membrane Surface ◽  
Membrane Bioreactors ◽  
Stable Operation ◽  
High Electron ◽  
Electrochemical Membrane Reactor ◽  
Anode Oxidation ◽  
Initial Stage

Abstract Membrane fouling is a considerable challenge for the stable operation of anaerobic membrane-based bioreactors. Membrane used as a cathode is a common measure to retard fouling growth in anaerobic electrochemical membrane bioreactors (AnEMBR), which; however, cannot avoid the fouling growth. Here we report a strategy using the membrane as an anode to resist membrane fouling in an AnEMBR. Although aggravating in the initial stage, the fouling on the anode membrane is gradually alleviated by the anode oxidation with enriching exoelectrogens to finally achieve a dynamic equilibrium between fouling growth and decomposition to maintain the operation stable. A mesh-like biofilter layer composed of cells with less extracellular polymeric substance (EPS) is formed on the membrane surface to lower the trans-membrane pressure and promote the interception of the anode membrane. The membrane has high electron storage and transfer capacities to accelerate the oxidation of the intercepted fouling materials, especially, the redundant EPSs of the biofilter layer.

scholarly journals Dynamical Modelling and Simulation of Wastewater Filtration Process by Submerged Membrane Bioreactors

2009 ◽  
Vol 7 (1) ◽  
Author(s):  
Alain Zarragoitia ◽  
Sylvie Schetrite ◽  
Ulises J. Jauregui-Haza ◽  
Claire Albasi
Keyword(s):  
Membrane Fouling ◽  
Membrane Surface ◽  
Model Development ◽  
Membrane Bioreactors ◽  
Transmembrane Pressure ◽  
Intermittent Aeration ◽  
Filtration Process ◽  
Solids Concentration ◽  
Wastewater Filtration ◽  
System Variables

A mathematical model was developed for the filtration process and the influence of aeration on Submerged Membrane Bioreactors. The dynamics of sludge attachment to and detachment from the membrane, in relation to the filtration and a strong intermittent aeration, were included in the model. The influence on the membrane fouling of intermittent aeration injected on the membrane surface, and its synchronization with intermittent filtration, were studied numerically and experimentally. For the evaluation of filtration cake development, the assumption of the presence of two cake layers (one dynamic and the other stable) was considered. The model development and simulation focused on the description of existing relationships among important system variables like mixed liquor suspended solids concentration, aeration, temperature of the sludge suspension, transmembrane pressure, and the fouling increase during the filtration process. The model obtained offers the possibility of improving the design configuration and operation strategies of Submerged Membrane Bioreactors in wastewater treatment, and it allows the of aeration-filtration cycles to be optimized.

scholarly journals Membrane Fouling – The Enemy of Forward Osmosis

2021 ◽  
Vol 25 (2) ◽  
pp. 73-88
Author(s):  
Z. H. Chang ◽  
Y. H. Teow ◽  
S. P. Yeap ◽  
J. Y. Sum
Keyword(s):  
Membrane Fouling ◽  
Membrane Separation ◽  
Membrane Surface ◽  
Forward Osmosis ◽  
Feed Solution ◽  
Separation Process ◽  
Nutrient Recovery ◽  
Water Reclamation ◽  
Water Permeation ◽  
Fouling Mechanism

Forward osmosis (FO) is an osmotically driven membrane separation process. It is potentially applied in various industries for nutrient recovery and water reclamation. Although FO showed a lesser fouling tendency than other pressure-driven membrane processes, the solutes in the feed solution would still deposit on the membrane surface, forming a fouling layer that resists water permeation. For that reason, fouling mitigation is a trending issue in the FO process. A better understanding of the fouling mechanism is required before opting for the appropriate strategy to mitigate it. This article describes the fouling mechanism based on different foulant presented in the feed, followed by a method in relieving fouling in the FO process.

Sign in / Sign up

Export Citation Format

Share Document