scholarly journals Effect and mechanism of reduced membrane bioreactor fouling by powdered activated carbon

2021 ◽  
Vol 83 (5) ◽  
pp. 1005-1016
Author(s):  
Yongji Zhang ◽  
Xiaotong Wang ◽  
Hexiu Ye ◽  
Lingling Zhou ◽  
Zhiling Zhao
Keyword(s):  
Activated Carbon ◽  
Membrane Fouling ◽  
Positive Impact ◽  
Membrane Surface ◽  
Polluted Water ◽  
Transmembrane Pressure ◽  
Carbon Membrane ◽  
Cake Layer ◽  
Cleaning Methods ◽  
Alkaline Cleaning

Abstract Powered Activated Carbon – Membrane Bioreactors (PAC-MBRs) have been used with good results for slightly polluted water treatment. Our batch experiments showed that the transmembrane pressure of a PAC-MBR was 25% less than that of a MBR in one period of test, which indicated that PAC did help control the fouling in MBRs. Based on this observation, several mechanisms of membrane fouling of MBRs and PAC-MBRs were investigated to have some insight into how PAC brought a positive impact. The total resistances decreased by 60% and different resistances were redistributed after adding PAC. The dominant one changed from filtration resistance to cake resistance. These smaller cake resistances resulted from the PAC because, showing in the scanning electron microscopy pictures, it made the cake layer looser and rougher than that on a normal membrane. Meanwhile, the analysis of the membrane eluent showed that the addition of PAC changed the microbial species and its metabolites on the membrane and effectively reduced the adsorption of hydrophilic organic molecules on the membrane surface. Additionally, PAC prevented polypeptide compounds from being trapped inside the pores of membranes, so the cake on the PAC-MBR contaminated membrane surface was easier to scrape off. In the test of cleaning methods, alkaline cleaning removed the most organics from contaminated membranes to restore membrane performance.

scholarly journals Pilot Study on the Combination of Different Pre-Treatments with Nanofiltration for Efficiently Restraining Membrane Fouling While Providing High-Quality Drinking Water

Membranes ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 380
Author(s):  
Yan Chen ◽  
Huiping Li ◽  
Weihai Pang ◽  
Baiqin Zhou ◽  
Tian Li ◽  
...  
Keyword(s):  
Drinking Water ◽  
Activated Carbon ◽  
Membrane Fouling ◽  
Membrane Surface ◽  
Post Treatment ◽  
Size Exclusion ◽  
Transmembrane Pressure ◽  
Feed Water ◽  
High Quality ◽  
Treated Water

Nanofiltration (NF) is a promising post-treatment technology for providing high-quality drinking water. However, membrane fouling remains a challenge to long-term NF in providing high-quality drinking water. Herein, we found that coupling pre-treatments (sand filtration (SF) and ozone–biological activated carbon (O3-BAC)) and NF is a potent tactic against membrane fouling while achieving high-quality drinking water. The pilot results showed that using SF+O3-BAC pre-treated water as the feed water resulted in a lower but a slowly rising transmembrane pressure (TMP) in NF post-treatment, whereas an opposite observation was found when using SF pre-treated water as the feed water. High-performance size-exclusion chromatography (HPSEC) and three-dimensional excitation–emission matrix (3D-EEM) fluorescence spectroscopy determined that the O3-BAC process changed the characteristic of dissolved organic matter (DOM), probably by removing the DOM of lower apparent molecular weight (LMW) and decreasing the biodegradability of water. Moreover, amino acids and tyrosine-like substances which were significantly related to medium and small molecule organics were found as the key foulants to membrane fouling. In addition, the accumulation of powdered activated carbon in O3-BAC pre-treated water on the membrane surface could be the key reason protecting the NF membrane from fouling.

scholarly journals Studies of polypropylene membrane fouling during microfiltration of broth with Citrobacter freundii bacteria

2015 ◽  
Vol 17 (4) ◽  
pp. 56-64 ◽  
Author(s):  
Marek Gryta ◽  
Marta Waszak ◽  
Maria Tomaszewska
Keyword(s):  
Membrane Fouling ◽  
Membrane Surface ◽  
Transmembrane Pressure ◽  
Citrobacter Freundii ◽  
Permeate Flux ◽  
Process Duration ◽  
Polypropylene Membrane ◽  
Flux Decline ◽  
Cake Layer ◽  
Scanning Electron

Abstract In this work a fouling study of polypropylene membranes used for microfiltration of glycerol solutions fermented by Citrobacter freundii bacteria was presented. The permeate free of C. freundii bacteria and having a turbidity in the range of 0.72–1.46 NTU was obtained. However, the initial permeate flux (100–110 L/m2h at 30 kPa of transmembrane pressure) was decreased 3–5 fold during 2–3 h of process duration. The performed scanning electron microscope observations confirmed that the filtered bacteria and suspensions present in the broth formed a cake layer on the membrane surface. A method of periodical module rinsing was used for restriction of the fouling influence on a flux decline. Rinsing with water removed most of the bacteria from the membrane surface, but did not permit to restore the initial permeate flux. It was confirmed that the irreversible fouling was dominated during broth filtration. The formed deposit was removed using a 1 wt% solution of sodium hydroxide as a rinsing solution.

scholarly journals Model-based evaluation of fouling mechanisms in powdered activated carbon/membrane bioreactor system

2019 ◽  
Vol 79 (10) ◽  
pp. 1844-1852 ◽  
Author(s):  
Juan Xiong ◽  
Xingtao Zuo ◽  
Shi Zhang ◽  
Wei Liao ◽  
Zhongbing Chen
Keyword(s):  
Activated Carbon ◽  
Membrane Bioreactor ◽  
Powdered Activated Carbon ◽  
Transmembrane Pressure ◽  
Carbon Membrane ◽  
Complete Model ◽  
Constant Flow Rate ◽  
Fouling Mechanism ◽  
Cake Layer ◽  
Mean Square Errors

Abstract Identifying the fouling degree of a membrane bioreactor (MBR) provides guidance on the determination of suitable membrane cleaning methods. There is still a lack of knowledge on the effects of powdered activated carbon (PAC) refresh ratio on the MBR fouling mechanism. Major fouling mechanisms of an MBR with constant flow rate at different PAC replenishment ratios were investigated by individual and combined mechanistic fouling models. The root mean square errors were employed to assess the prediction accuracy of the used fouling models. The combined models showed better prediction. The cake–complete model provided far better fits of the transmembrane pressure data, and provided good fits of other individual model predictions regardless of the PAC refreshment ratio. Fourier transform infrared spectroscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy confirmed that the cake layer clogging was the main fouling mechanism followed by complete blockage and standard plugging. The cake–complete model may be used to predict the fouling mechanisms in PAC/MBR systems.

Exerting ultrasound to control the membrane fouling in filtration of anaerobic activated sludge—mechanism and membrane damage

2008 ◽  
Vol 57 (5) ◽  
pp. 773-779 ◽  
Author(s):  
Xianghua Wen ◽  
Pengzhe Sui ◽  
Xia Huang
Keyword(s):  
Activated Sludge ◽  
Hydroxyl Radicals ◽  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Chemical Interaction ◽  
Membrane Surface ◽  
Membrane Damage ◽  
Operational Conditions ◽  
Fouling Control ◽  
Cake Layer

In this study, ultrasound was applied to control membrane fouling development online in an anaerobic membrane bioreactor (AMBR). Experimental results showed that membrane fouling could be controlled effectively by ultrasound although membrane damage may occur under some operational conditions. Based upon the observation on the damaged membrane surface via SEM, two mechanisms causing membrane damage by exerting ultrasound are inferred as micro particle collide on the membrane surface and chemical interaction between membrane materials and hydroxyl radicals produced by acoustic cavitations. Not only membrane damage but also membrane fouling control and membrane fouling cleaning were resulted from these mechanisms. Properly selecting ultrasonic intensity and working time, and keeping a certain thickness of cake layer on membrane surface could be effective ways to protect membrane against damage.

scholarly journals Ozone Chemically Enhanced Backwash for Ceramic Membrane Fouling Control in Cyanobacteria-Laden Water

Membranes ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 213
Author(s):  
Stéphane Venne ◽  
Onita D. Basu ◽  
Benoit Barbeau
Keyword(s):  
Surface Water ◽  
Surface Waters ◽  
Membrane Fouling ◽  
Ceramic Membrane ◽  
Membrane Surface ◽  
Operating Costs ◽  
Fouling Control ◽  
Dead End ◽  
Cake Layer ◽  
Flow Experiments

Membrane fouling in surface waters impacted by cyanobacteria is currently poorly controlled and results in high operating costs. A chemically enhanced backwash (CEB) is one possible strategy to mitigate cyanobacteria fouling. This research investigates the potential of using an ozone CEB to control the fouling caused by Microcystis aeruginosa in filtered surface water on a ceramic ultrafiltration membrane. Batch ozonation tests and dead-end, continuous flow experiments were conducted with ozone doses between 0 and 19 mg O3/mg carbon. In all tests, the ozone was shown to react more rapidly with the filtered surface water foulants than with cyanobacteria. In addition, the ozone CEB demonstrated an improved mitigation of irreversible fouling over 2 cycles versus a single CEB cycle; indicating that the ozone CEB functioned better as the cake layer developed. Ozone likely weakens the compressible cake layer formed by cyanobacteria on the membrane surface during filtration, which then becomes more hydraulically reversible. In fact, the ozone CEB reduced the fouling resistance by 35% more than the hydraulic backwash when the cake was more compressed.

scholarly journals The removal of typical pollutants in secondary effluent by the combined process of powdered activated carbon–ultrafiltration

2017 ◽  
Vol 75 (6) ◽  
pp. 1485-1493 ◽  
Author(s):  
Lihua Sun ◽  
Ning He ◽  
Tianmin Yu ◽  
Xi Duan ◽  
Cuimin Feng ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Membrane Fouling ◽  
Filter Cake ◽  
Powdered Activated Carbon ◽  
Secondary Effluent ◽  
Moderate Amount ◽  
Combined Process ◽  
Membrane Flux ◽  
Initial Stage ◽  
Cake Layer

This paper focused on the effects of powdered activated carbon (PAC) dosage on ultrafiltration (UF) membrane flux caused by natural organic matter (NOM). Three model foulants, humic acid (HA), bovine serum albumin (BSA) and sodium alginate (SA), were adopted to represent different NOM fractions in secondary effluent treated by the combined process of PAC-UF. Moreover, the membrane fouling resistance and fouling mechanism were also analyzed. The results indicated that the best PAC dosage for the membrane flux variation was 20 mg/L for HA and SA, and 10 mg/L for BSA. SA caused the most serious membrane fouling, which was mainly reversible fouling. The membrane fouling caused by HA and BSA was mainly irreversible membrane fouling. The membrane fouling caused by organics happened mainly at the initial stage of filtration. Because the filter cake layer formed by a moderate amount of PAC could intercept organics, the membrane fouling, especially the irreversible fouling, could be reduced.

Ammonia oxidation at low temperature in a high concentration powdered activated carbon membrane bioreactor

2002 ◽  
Vol 2 (2) ◽  
pp. 169-176 ◽  
Author(s):  
G. Seo ◽  
S. Takizawa ◽  
S. Ohgaki
Keyword(s):  
Activated Carbon ◽  
Water Temperature ◽  
Membrane Bioreactor ◽  
Ammonia Oxidation ◽  
Hollow Fiber Membrane ◽  
Powdered Activated Carbon ◽  
Carbon Membrane ◽  
High Concentration ◽  
Filtration Resistance ◽  
Cake Layer

In this study, a membrane bioreactor (MBR) with high concentration of powdered activated carbon was investigated to enhance the oxidation of ammonia at a water temperature lower than 4°C. A semi-pilot scale submersed suction type MBR was operated with a hollow fiber membrane module having a nominal pore size of 0.1μm and an effective filtration area of 0.05 m2. A powder activated carbon (PAC) concentration of 40 g/L was maintained in the reactor and the PAC was not replaced during the experiment. A control reactor without PAC was also operated for comparison. Water temperature of both reactors was controlled at 25, 10, 4 and 2°C. At a water temperature of 4°C, the influent ammonia nitrogen of 10 mg/L was removed completely in the reactor with PAC. On the other hand, the effluent concentration of the control reactor was fluctuated in a range of 3-6 mg/L. In addition, nitrite nitrogen was detected in the control reactor up to a maximum concentration of 6 mg/L at the same temperature. Still high removal efficiency was obtained in the reactor with PAC even at 2°C, but almost no ammonia oxidation was observed in the control reactor. The average ammonia oxidation rate of the powdered activated carbon reactor was 1.3-3.2 mg/L.h, which is 4.5 times higher than that of the control (0.51-0.63 mg/L.h). Filtration resistance was 2.45 × 1012m-1 for the reactor with PAC, which is one order lower than that of the control reactor (1.64 × 1013m-1). The microbial cake layer on the membrane surface caused the larger filtration resistance for the control reactor. Only one chemical cleaning was conducted for the membrane in the PAC reactor at the flux of 0.4-0.7 m/d while 3 times cleaning was required for that of the control.

Evaluating submicron-sized activated carbon adsorption for microfiltration pretreatment

2006 ◽  
Vol 6 (1) ◽  
pp. 149-155 ◽  
Author(s):  
Y. Matsui ◽  
T. Sanogawa ◽  
N. Aoki ◽  
S. Mima ◽  
T. Matsushita
Keyword(s):  
Activated Carbon ◽  
Adsorption Kinetics ◽  
Membrane Fouling ◽  
Flow Reactor ◽  
Laboratory Scale ◽  
Transmembrane Pressure ◽  
Activated Carbon Adsorption ◽  
Membrane Unit ◽  
Tubular Flow Reactor ◽  
Tubular Flow

Submicron powdered activated carbon (PAC) rapidly adsorbed natural organic matter (NOM) fromwater samples: a batch test of the adsorption kinetics showed that the NOM concentration dropped substantially within 15 s and then leveled off. In a tubular flow reactor test, NOM removal after a 15 s contact time was almost the same as removal values attained at longer contact times. Laboratory-scale and bench-scale pilotplant ceramic microfiltration (MF) experiments with submicron PAC adsorption pretreatment were conducted to evaluate NOM removal and to examine the effect of the PAC on filterability. The laboratory scale MF experiment revealed that PAC adsorption pretreatment could be accomplished with a detention (2.4 s) that was much shorter than the time expected from the adsorption kinetics test. This result suggests that adsorption pretreatment for MF could be accomplished by adding the submicron PAC directly into the feed line to the membrane and that installation of a special PAC contactor before the membrane unit is unnecessary. Although micron PAC rather than submicron PAC was used unintentionally in the pilot plant experiment, these PAC showed much better NOM removal than normal PAC, and no adverse effects, such as transmembrane pressure buildup and reversible or irreversible membrane fouling, were observed.

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.

Sign in / Sign up

Export Citation Format

Share Document