Domestic wastewater treatment by a submerged MBR (membrane bio-reactor) with enhanced air sparging

2003 ◽  
Vol 47 (12) ◽  
pp. 149-154 ◽  
Author(s):  
I.-S. Chang ◽  
S.J. Judd
Keyword(s):  
Wastewater Treatment ◽  
Membrane Fouling ◽  
Gas Flow ◽  
Domestic Wastewater ◽  
Air Sparging ◽  
Air Jet ◽  
Dead End ◽  
Membrane Tube ◽  
Cake Layer ◽  
Air Lift

The air sparging technique has been recognised as an effective way to control membrane fouling. However, its application to a submerged MBR (Membrane Bio-Reactor) has not yet been reported. This paper deals with the performances of air sparging on a submerged MBR for wastewater treatment. Two kinds of air sparging techniques were used respectively. First, air is injected into the membrane tube channels so that mixed liquor can circulate in the bioreactor (air-lift mode). Second, a periodic air-jet into the membrane tube is introduced (air-jet mode). Their applicability was evaluated with a series of lab-scale experiments using domestic wastewater. The flux increased from 23 to 33 lm−2h−1 (43% enhancement) when air was injected for the air-lift module. But further increase of flux was not observed as the gas flow increased. The Rc/(Rc+Rf), ratio of cake resistance (Rc) to sum of Rc and Rf (internal fouling resistance), was 23%, indicating that the Rc is not the predominant resistance unlike other MBR studies. It showed that the cake layer was removed sufficiently due to the air injection. Thus, an increase of air flow could not affect the flux performance. The air-jet module suffered from a clogging problem with accumulated sludge inside the lumen. Because the air-jet module has characteristics of dead end filtration, a periodic air-jet was not enough to blast all the accumulated sludge out. But flux was greater than in the air-lift module if the clogging was prevented by an appropriate cleaning regime such as periodical backwashing.

scholarly journals Fouling Mechanisms Analysis via Combined Fouling Models for Surface Water Ultrafiltration Process

Membranes ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 149 ◽  
Author(s):  
Bin Huang ◽  
Hangkun Gu ◽  
Kang Xiao ◽  
Fangshu Qu ◽  
Huarong Yu ◽  
...  
Keyword(s):  
Water Treatment ◽  
Surface Water ◽  
Membrane Fouling ◽  
Mechanism Analysis ◽  
Surface Water Treatment ◽  
Dead End ◽  
Cake Layer ◽  
Significant Difference ◽  
Combined Models ◽  
And Control

Membrane fouling is still the bottleneck affecting the technical and economic performance of the ultrafiltration (UF) process for the surface water treatment. It is very important to accurately understand fouling mechanisms to effectively prevent and control UF fouling. The rejection performance and fouling mechanisms of the UF membrane for raw and coagulated surface water treatment were investigated under the cycle operation of constant-pressure dead-end filtration and backwash. There was no significant difference in the UF permeate quality of raw and coagulated surface water. Coagulation mainly removed substances causing turbidity in raw surface water (including most suspended particles and a few organic colloids) and thus mitigated UF fouling effectively. Backwash showed limited fouling removal. For the UF process of both raw and coagulated surface water, the fittings using single models showed good linearity for multiple models mainly due to statistical illusions, while the fittings using combined models showed that only the combined complete blocking and cake layer model fitted well. The quantitative calculations showed that complete blocking was the main reason causing flux decline. Membrane fouling mechanism analysis based on combined models could provide theoretical supports to prevent and control UF fouling for surface water treatment.

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.

Membrane fouling and performance evaluation of conventional membrane bioreactor (MBR), moving biofilm MBR and oxic/anoxic MBR

2014 ◽  
Vol 69 (7) ◽  
pp. 1403-1409 ◽  
Author(s):  
Sher Jamal Khan ◽  
Aman Ahmad ◽  
Muhammad Saqib Nawaz ◽  
Nicholas P. Hankins
Keyword(s):  
Membrane Fouling ◽  
Extracellular Polymeric Substances ◽  
Water Flux ◽  
Oxygen Demand ◽  
Domestic Wastewater ◽  
Membrane Bioreactors ◽  
Nitrogen And Phosphorus ◽  
Biofilm Carrier ◽  
Cake Layer ◽  
And Performance

In this study, three laboratory scale submerged membrane bioreactors (MBRs) comprising a conventional MBR (C-MBR), moving bed MBR (MB-MBR) and anoxic-oxic MBR (A/O-MBR) were continuously operated with synthesized domestic wastewater (chemical oxygen demand, COD = 500 mg/L) for 150 days under similar operational and environmental conditions. Kaldnes® plastic media with 20% dry volume was used as a biofilm carrier in the MB-MBR and A/O-MBR. The treatment performance and fouling propensity of the MBRs were evaluated. The effect of cake layer formation in all three MBRs was almost the same. However, pore blocking caused a major difference in the resultant water flux. The A/O-MBR showed the highest total nitrogen and phosphorus (PO4-P) removal efficiencies of 83.2 and 69.7%, respectively. Due to the high removal of nitrogen, fewer protein contents were found in the soluble and bound extracellular polymeric substances (EPS) of the A/O-MBR. Fouling trends of the MBRs showed 12, 14 and 20 days filtration cycles for C-MBR, MB-MBR and A/O-MBR, respectively. A 25% reduction of the soluble EPS and a 37% reduction of the bound EPS concentrations in A/O-MBR compared with C-MBR was a major contributing factor for fouling retardation and the enhanced filtration capacity of the A/O-MBR.

Application of Bdellovibrio bacteriovorus for reducing fouling of membranes used for wastewater treatment

2018 ◽  
Vol 43 (3) ◽  
pp. 296-305 ◽  
Author(s):  
Melek Özkan ◽  
Hilal Yılmaz ◽  
Merve Akay Çelik ◽  
Çişel Şengezer ◽  
Elif Erhan ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Membrane Fouling ◽  
Membrane Surface ◽  
Hybridization Technique ◽  
Fish Analysis ◽  
Bdellovibrio Bacteriovorus ◽  
Steady State Condition ◽  
Dead End ◽  
Pure Cultures

Abstract Background: Membrane bioreactor (MBR) systems used for wastewater treatment (WWT) processes are regarded as clean technologies. Degradation capacity of the predator bacterium, Bdellovibrio bacteriovorus, was used as a cleaning strategy for reducing membrane fouling. Method: Wastewater with different sludge age and hydraulic retention time were filtered through Poly(ether)sulphone (PES) membranes using dead end reactor. Change in filtration performance after cleaning of membrane surface by B. bacteriovorus was measured by comparison of flux values. Bacterial community of the sludge was determined by 16SrRNA sequence analysis. Community profile of membrane surface was analyzed by fluorescent in situ hybridization technique. Results: After cleaning of MP005 and UP150 membranes with predator bacteria, 4.8 L/m2·h and 2.04 L/m2·h increase in stable flux at steady state condition was obtained as compared to the control, respectively. Aeromonas, Proteus, and Alcaligenes species were found to be dominant members of the sludge. Bdellovibrio bacteriovorus lysed pure cultures of the isolated sludge bacteria successfully. FISH analysis of the membrane surface showed that Alfa-proteobacteria are the most numerous bacteria among the biofilm community on the membrane surface. Conclusion: Results suggested that cleaning of MBR membranes with B. bacteriovorus has a potential to be used as a biological cleaning method.

scholarly journals Influence of relaxation modes on membrane fouling in submerged membrane bioreactor for domestic wastewater treatment

Chemosphere ◽  
2017 ◽  
Vol 181 ◽  
pp. 19-25 ◽  
Author(s):  
Rasikh Habib ◽  
Muhammad Bilal Asif ◽  
Sidra Iftekhar ◽  
Zahiruddin Khan ◽  
Khum Gurung ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Domestic Wastewater ◽  
Submerged Membrane Bioreactor ◽  
Domestic Wastewater Treatment ◽  
Relaxation Modes

Electrophoresis in Membrane Separation Processes: From Lab to Field Scale Experiments

2006 ◽  
Vol 314 ◽  
pp. 257-262
Author(s):  
G. Falk
Keyword(s):  
Waste Water ◽  
Wastewater Treatment ◽  
Water Treatment ◽  
Membrane Fouling ◽  
Membrane Separation ◽  
Waste Water Treatment ◽  
Domestic Wastewater ◽  
Field Scale ◽  
Specific Energy Input ◽  
Processing Scheme

In this paper results of electrophoretically activated processes for domestic wastewater treatment in lab and field scale experiments are presented. The principal mechanisms of non-membrane and membrane based electrokinetic solid liquid separation by electrophoresis are described. In the case of non-membrane based electrokinetic wastewater treatment a modular processing scheme is suggested in order to achieve economically and ecologically suitable processing conditions based on colloidal wastewater characteristics. In the case of membrane based electrokinetic waste water treatment an effective anti-membrane fouling process is designed controlled by colloidal characteristics of the wastewater, especially zetapotential, as well as external field parameters and microfiltration module geometries. The specific energy input of the membrane based and non-membrane based electrophoretic waste water treatment methodologies are compared and future perspectives of electrokinetic activated waste water purification processes are proposed.

scholarly journals Mechanism of Membrane Fouling Control by HMBR: Effect of Microbial Community on EPS

2020 ◽  
Vol 17 (5) ◽  
pp. 1681
Author(s):  
Qiang Liu ◽  
Ying Yao ◽  
Delan Xu
Keyword(s):  
Microbial Community ◽  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Extracellular Polymeric Substances ◽  
Microbial Community Composition ◽  
Domestic Wastewater ◽  
Control Group ◽  
Transmembrane Pressure ◽  
Fouling Control ◽  
Cake Layer

A hybrid membrane bioreactor (HMBR) employing activated sludge and biofilm simultaneously is proved to represent a good performance on membrane fouling control compared to conventional membrane bioreactor (CMBR) by reducing extracellular polymeric substances (EPS), especially bound EPS (B-EPS). In order to better understand the mechanism of membrane fouling control by the HMBR in regard of microbial community composition, a pilot scale HMBR operated to treat domestic wastewater for six months, and a CMBR operated at the same time as control group. Results showed that HMBR can effectively control membrane fouling. When transmembrane pressure reached 0.1 MPa, the membrane module in the HMBR operated for about 26.7% longer than that in the CMBR. In the HMBR, the quantity of EPS was significantly lower than that in the CMBR. In this paper, soluble EPS was also found to have a close relationship with cake layer resistance. The species richness and diversity in the HMBR were higher than those in the CMBR, and a certain difference between the compositions of microbial communities in the two reactors was confirmed. Therefore, the difference in microbial community compositions may be the direct reason why EPS in the HMBR was lower than that in the CMBR.

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