Direct observations of membrane scale in membrane bioreactor for wastewater treatment application

2010 ◽  
Vol 61 (9) ◽  
pp. 2267-2272 ◽  
Author(s):  
J. Kim ◽  
T. I. Yoon
Keyword(s):  
Citric Acid ◽  
Sodium Hypochlorite ◽  
Membrane Bioreactor ◽  
Membrane Surface ◽  
Pilot Scale ◽  
Scale Formation ◽  
Membrane Pores ◽  
Direct Observations ◽  
Treatment Application ◽  
Inorganic Fouling

The formation of inorganic fouling on MF membrane was investigated in membrane bioreactor (MBR) treating industrial wastewater. Membrane autopsy works using microscopic techniques and surface analysis were carried out at the completion of pilot-scale operation to analyze foulant materials extensively. Scaling occurred on the membrane surface significantly in the MBR treating calcium-rich wastewater (LSI > 2.0). Our experiments showed that the coverage of the membrane surface by the inorganic fouling consisted mostly of calcium while the internal fouling within membrane pores due to the scale formation was almost negligible. Most of calcium was rejected on the MF membrane surface as scale formation of calcium carbonate (>90% as rejection). The sequence sodium hypochlorite-citric acid for the removal of membrane scale was more effective than the sequence citric acid-sodium hypochlorite cleaning. It appeared that the structure of organic compounds combined with calcium became loose by the addition of the sodium hypochlorite, thereby releasing calcium more easily from the membrane by applying the acid cleaning agent.

Alternative energy efficient membrane bioreactor using reciprocating submerged membrane

2014 ◽  
Vol 70 (12) ◽  
pp. 1998-2003 ◽  
Author(s):  
J. Ho ◽  
S. Smith ◽  
H. K. Roh
Keyword(s):  
Energy Consumption ◽  
Energy Efficient ◽  
Alternative Energy ◽  
Membrane Bioreactor ◽  
Hollow Fiber Membrane ◽  
Membrane Surface ◽  
Specific Energy Consumption ◽  
Pilot Scale ◽  
Transmembrane Pressure ◽  
Flow Conditions

A novel membrane bioreactor (MBR) pilot system, using membrane reciprocation instead of air scouring, was operated at constant high flux and daily fluctuating flux to demonstrate its application under peak and diurnal flow conditions. Low and stable transmembrane pressure was achieved at 40 l/m2/h (LMH) by use of repetitive membrane reciprocation. The results reveal that the inertial forces acting on the membrane fibers effectively propel foulants from the membrane surface. Reciprocation of the hollow fiber membrane is beneficial for the constant removal of solids that may build up on the membrane surface and inside the membrane bundle. The membrane reciprocation in the reciprocating MBR pilot consumed less energy than coarse air scouring used in conventional MBR systems. Specific energy consumption for the membrane reciprocation was 0.072 kWh/m3 permeate produced at 40 LMH flux, which is 75% less than for a conventional air scouring system as reported in literature without consideration of energy consumption for biological aeration (0.29 kWh/m3). The daily fluctuating flux test confirmed that the membrane reciprocation is effective to handle fluctuating flux up to 50 LMH. The pilot-scale reciprocating MBR system successfully demonstrated that fouling can be controlled via 0.43 Hz membrane reciprocation with 44 mm or higher amplitude.

scholarly journals Membrane Fouling Monitoring in a Submerged Membrane Bioreactor

Proceedings ◽  
2018 ◽  
Vol 2 (11) ◽  
pp. 653
Author(s):  
Konstantinos Azis ◽  
Marianthi Malioka ◽  
Spyridon Ntougias ◽  
Paraschos Melidis
Keyword(s):  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Municipal Wastewater ◽  
Membrane Surface ◽  
Cross Flow ◽  
Pilot Scale ◽  
Municipal Wastewater Treatment ◽  
Membrane Performance ◽  
Conventional Activated Sludge ◽  
Major Disadvantage

Use of Membrane Bioreactor (MBR) technology for municipal wastewater treatment has been increased in recent years, as it successfully overcomes the disadvantages of the conventional activated sludge process. Membrane fouling is the major disadvantage of MBRs and leads to decreased membrane performance and expanded operational expenses. In this study, fouling was monitored in a pilot-scale submerged MBR system fed with municipal wastewater. TMP was directly measured on the membrane module during the operation. To control TMP increase owing to biosolids accumulation on membrane surface, successive backwashes and air-cross flow velocity increase were applied. These measures lowered TMP and improved flux.

Performance evaluation of a novel reciprocation membrane bioreactor (rMBR) for enhanced nutrient removal in wastewater treatment: a comparative study

2015 ◽  
Vol 72 (6) ◽  
pp. 917-927 ◽  
Author(s):  
Jaeho Ho ◽  
Shaleena Smith ◽  
Gyu Dong Kim ◽  
Hyung Keun Roh
Keyword(s):  
Wastewater Treatment ◽  
Energy Consumption ◽  
Membrane Bioreactor ◽  
Membrane Surface ◽  
Operating Performance ◽  
Specific Energy Consumption ◽  
Treatment Plant ◽  
Pilot Scale ◽  
Reciprocating Motion ◽  
Membrane Cleaning

This study compared and evaluated the performance of a conventional membrane bioreactor (MBR) and a novel reciprocation MBR (rMBR) which used mechanical membrane reciprocation in place of membrane air scouring in pilot-scale tests. Each system was independently operated for 280 days at a local wastewater treatment plant for a parallel assessment of operating performance. The rMBR was found to be more effective than the MBR with regard to operating performance and energy consumption. Inertial forces created by the reciprocating motion shook foulants from the membrane surface. In addition, because of the looseness of the fibers, they moved relative to each other during reciprocation thus preventing sludge clogging inside the fiber bundle. Because the rMBR does not use aeration for membrane cleaning, the membrane tank in the rMBR maintained anoxic conditions, allowing endogenous denitrification in the membrane tank. The rMBR permeate contained an average of 1.7 mg/L total nitrogen (TN) with less than 1 mg/L NO3-N, while the TN concentration in the MBR permeate averaged 5 mg/L with 3.5 mg/L NO3-N. The specific energy consumption for membrane reciprocation in the rMBR was 0.064 kWh/m3, while that for air scouring in the MBR was 0.19 kWh/m3.

scholarly journals The Impact of Mechanically-Imposed Shear on Clogging, Fouling and Energy Demand for an Immersed Membrane Bioreactor

Membranes ◽  
2018 ◽  
Vol 8 (4) ◽  
pp. 104 ◽  
Author(s):  
Simon Judd ◽  
Albert Odai ◽  
Pompilia Buzatu ◽  
Hazim Qiblawey
Keyword(s):  
Energy Demand ◽  
Membrane Bioreactor ◽  
Membrane Surface ◽  
Petroleum Industry ◽  
Pilot Scale ◽  
Hollow Fibre ◽  
Transmembrane Pressure ◽  
Flat Sheet ◽  
Industry Effluent ◽  
The Impact

The impact of the application of mechanically-imposed shear on the propensity for fouling and clogging (or “sludging”—the agglomeration of sludge solids in the membrane channel) of an immersed flat sheet (iFS) membrane bioreactor (MBR) was studied. The bench-scale test cell used contained a single flat sheet fitted with a crank and motor to allow the membrane to be oscillated (or reciprocated) vertically at a low rate (20 RPM). The membrane was challenged with sludge samples from a local MBR installation treating petroleum industry effluent, the sludge having previously been demonstrated as having a high sludging propensity. Sludging was measured by direct visual observation of membrane surface occlusion by the agglomerated solids, with fouling being notionally represented by the rate of transmembrane pressure increase. Results demonstrated membrane reciprocation to have a more beneficial impact on sludging amelioration than on suppressing fouling. Compared with the stationary membrane, sludging was reduced by an average of 45% compared with only 13% for fouling suppression at the reference flux of 15 L·m−2·h−1 applied. The specific energy demand of the mechanical shear application was calculated as being around 0.0081 kWh·m−3, significantly lower than values reported from a recent pilot scale study on a reciprocated immersed hollow fibre MBR. Whilst results appear promising in terms of energy efficiency, it is likely that the mechanical complexity of applying membrane movement would limit the practical application to low flows, and a correspondingly small number of membrane modules.

Leakage of Endotoxins through the Endotoxin Retentive Filter: An in vitro Study

2022 ◽  
pp. 1-9
Author(s):  
Hiroshi Nozaki ◽  
Yoshihiro Tange ◽  
Yoji Inada ◽  
Takashi Uchino ◽  
Nakanobu Azuma
Keyword(s):  
Sodium Hypochlorite ◽  
Peracetic Acid ◽  
In Vitro Study ◽  
Dialysis Fluid ◽  
High Concentration ◽  
Membrane Pores ◽  
Polyether Sulfone ◽  
Repeated Use ◽  
High Concentrations

<b><i>Introduction:</i></b> Ultrapurification of dialysis fluid has enabled highly efficient dialysis treatments. Online hemodiafiltration is one such treatment that uses a purified dialysis fluid as a supplemental fluid. In this method, an endotoxin retentive filter (ETRF) is used in the final step of dialysis fluid purification, with the aim of preventing leakage of endotoxins. Sodium hypochlorite and peracetic acid are used as disinfecting agents for the dialysis fluid pipes containing the ETRF; however, the effects of these agents on ETRF membrane pores have not been fully clarified. <b><i>Methods:</i></b> Water permeability (flux) and endotoxin permeability were assessed in 3 types of ETRFs made with different membrane materials: polyester polymer alloy (PEPA), polyether sulfone (PES), and polysulfone (PS). High-concentration sodium hypochlorite and 2 types of peracetic acid were used as disinfecting agents, and the changes in flux and the endotoxin sieving coefficient (SC) were measured. <b><i>Results:</i></b> After repeated use of high concentrations of sodium hypochlorite and peracetic acid, the PEPA and PES ETRFs did not permit passage of endotoxins, regardless of their flux. However, in the PS ETRF, the flux and endotoxin SC increased with the number of cleaning cycles. No differences were observed according to the concentration of peracetic acid disinfecting agents. <b><i>Conclusion:</i></b> PEPA and PES ETRFs completely prevent endotoxin leakage and can be disinfected at concentrations higher than the conventionally recommended concentration without affecting pore expansion. Even new PS ETRFs have low levels of endotoxin leakage, which increase after disinfection cycles using sodium hypochlorite and peracetic acid.

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