Critical flux aspect of air sparging and backflushing on membrane bioreactors

Desalination ◽  
2005 ◽  
Vol 175 (1) ◽  
pp. 61-71 ◽  
Author(s):  
C. Psoch ◽  
S. Schiewer
Keyword(s):  
Membrane Bioreactors ◽  
Air Sparging ◽  
Critical Flux

Methods for understanding organic fouling in MBRs

2004 ◽  
Vol 49 (2) ◽  
pp. 237-244 ◽  
Author(s):  
B. Jefferson ◽  
A. Brookes ◽  
P. Le Clech ◽  
S.J. Judd
Keyword(s):  
Organic Carbon ◽  
Membrane Permeability ◽  
Membrane Bioreactors ◽  
Specific Reference ◽  
Critical Flux ◽  
Valuable Data ◽  
Organic Fouling ◽  
Soluble Organic Carbon ◽  
Carbon Concentrations

The identification and quantification of foulants in membrane bioreactors present a major challenge due to their complexity resulting from biomass heterogeneity. Fouling is normally characterised with respect to the critical flux, this being conventionally viewed as being the flux below which a reduction in membrane permeability does not take place. However, recent studies have revealed that such fouling arises even at very low fluxes. Moreover, fouling rates can differ substantially between different experiments, trials and installations even when operated under apparently similar conditions of biomass and soluble organic carbon concentrations. The methods available for quantifying and analysing fouling are reviewed with specific reference to recent data on sub-critical flux behaviour. It is concluded that HPSEC analysis of extracted biomass fractions may provide the most valuable data towards the determination of differences in fouling propensity between different biomasses, as inferred in conventional flux step analysis.

Critical flux in submerged membrane bioreactors for municipal wastewater treatment

Desalination ◽  
2009 ◽  
Vol 245 (1-3) ◽  
pp. 748-753 ◽  
Author(s):  
A. Bottino ◽  
G. Capannelli ◽  
A. Comite ◽  
R. Mangano
Keyword(s):  
Wastewater Treatment ◽  
Municipal Wastewater ◽  
Membrane Bioreactors ◽  
Municipal Wastewater Treatment ◽  
Critical Flux

Filterability assessment in membrane bioreactors using an in-situ filtration test cell

2010 ◽  
Vol 61 (11) ◽  
pp. 2809-2816 ◽  
Author(s):  
Teresa de la Torre ◽  
Moritz Mottschall ◽  
Boris Lesjean ◽  
Anja Drews ◽  
Andrew Iheanaetu ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Membrane Filtration ◽  
Membrane Bioreactors ◽  
Operating Conditions ◽  
Test Cell ◽  
New Method ◽  
Hysteresis Curve ◽  
Critical Flux ◽  
Filtration Method

A new method for the assessment of the filterability in membrane bioreactors was tested for five months in four MBR units in Berlin. The new method BFM (Berlin Filtration Method) for filterability assessment uses a small membrane filtration test cell which can be submerged directly in the biological tanks to determine the filterability of the activated sludge in-situ. The test cell contains an aerated flat-sheet membrane which operates at similar conditions as in the plant. Filterability is expressed in terms of critical flux obtained by performing flux-stepping experiments. The ultimate goal of monitoring the filterability with the device is to detect in real time fouling occurrences due to changes in sludge composition and to adapt accordingly the operating conditions. The usefulness of the device for this purpose was evaluated for five months after monitoring four MBR plants in Berlin with different activated sludge characteristics (MLSS from 5 to 21 g/L, SRT 12–35 d and COD in the supernatant 30–400 mg/L). The first results show a good agreement between the filterability of the sludge with the portable filtration test cell and the filtration performance of the plant. Critical flux values varied between 3 and 30 L/m2 h during the studied period. Useful information concerning the irreversibility of the fouling was provided by looking at the hysteresis curve of the flux-stepping experiments.

Fouling control in submerged membrane bioreactors

2005 ◽  
Vol 51 (6-7) ◽  
pp. 27-34 ◽  
Author(s):  
S. Judd
Keyword(s):  
Hydraulic Performance ◽  
Membrane Bioreactors ◽  
Specific Reference ◽  
Critical Flux ◽  
Fouling Control ◽  
Commercially Important ◽  
The Impact

The impact of fouling on the operation of submerged membrane bioreactors (MBRs) is discussed. The discussion proceeds through a review of the impacts of fouling and fouling speciation, with correlations of filterability against candidate foulants being provided. There follows a brief comparison of hydraulic performance of the submerged and sidestream configurations: data is presented to demonstrate the efficacy of coarse bubble aeration in the submerged MBR. The critical flux concept is then discussed and its applicability to MBRs deliberated in view of recent publications demonstrating fouling under sub-critical flux conditions. Finally, the two most commercially important MBR products are briefly reviewed with specific reference to design and operation for fouling amelioration.

Long-term use of the critical flux for fouling control in membrane bioreactors treating different industrial effluents: bench and pilot scale

2014 ◽  
Vol 55 (4) ◽  
pp. 859-869 ◽  
Author(s):  
Míriam Cristina Santos Amaral ◽  
Laura Hamdan de Andrade ◽  
Luzia Sergina França Neta ◽  
Wagner Guadagnin Moravia
Keyword(s):  
Industrial Effluents ◽  
Pilot Scale ◽  
Membrane Bioreactors ◽  
Critical Flux ◽  
Fouling Control

Membrane Processes in Water and Wastewater Treatment

2020 ◽  
pp. 109-136
Keyword(s):  
Lower Energy ◽  
Energy Requirement ◽  
Membrane Bioreactors ◽  
Water And Wastewater Treatment ◽  
Membrane Processes ◽  
Critical Flux ◽  
Liquid Phases ◽  
Water And Wastewater ◽  
Contaminants Removal ◽  
Membrane Technologies

Membrane technologies play a very important role in water and wastewater treatments. These membrane processes provide key advantages over the conventional processes, such as lower energy requirement, lower footprint, easier to operate, and more effective contaminants removal. This chapter introduces different membrane processes: (1) pressure-driven membrane processes which are the most widely used in water and wastewater treatments, and (2) several advanced membrane processes. These processes perform physical or physicochemical separations. Most of the separations occur between liquid-liquid phases, but liquid-gas and gas-gas separation phases are also performed in the latest membrane development. The contemporary membrane bioreactor is the heart of membrane technologies that are used in various applications. However, fouling is a common phenomenon that reduces the efficiency of the membrane operation. Thus, the concept of critical flux and introduction of some control and preventive mechanism could prevent or reduce the fouling in membrane bioreactors.

Membrane bioreactors and their role in wastewater reuse

2000 ◽  
Vol 41 (1) ◽  
pp. 197-204 ◽  
Author(s):  
B. Jefferson ◽  
A.L. Laine ◽  
S.J. Judd ◽  
T. Stephenson
Keyword(s):  
Water Quality ◽  
Wastewater Reuse ◽  
Membrane Bioreactors ◽  
Water Recycling ◽  
Grey Water ◽  
Critical Flux ◽  
Loading Rates ◽  
Membrane Aeration ◽  
Influent Water ◽  
Volumetric Loading

The potential of membrane aeration bioreactors (MABR), biological aerated filters (BAF) and membrane bioreactors (MBR) for grey water recycling has been evaluated. The MBR demonstrated the highest efficacy towards grey water recycling in terms of the three main water quality determinants of CBOD5, turbidity and total coliforms, providing 100% compliance in all cases. The membrane provided a solid free effluent and a biological culture adapted to treat the relatively difficult to degrade fractions of the grey water. The initial flux rate through the system was 28 l m−2h−1, which then gradually decreased to a stable level of 8 l m−2h−1. This demonstrated the process to be operating under sub critical flux conditions where no irreversible fouling occurs. Volumetric loading rates were correspondingly low due to the low flux rates and the weak strength of grey water, but process efficacy remained high throughout the loading rate range of 0.005–0.11 kgBOD m−3d−1 employed. The MBR was seen as particularly suitable as it was very effective at stabilising influent water quality variations and acted as a disinfection barrier to the water, providing a disinfection mechanism.

Sign in / Sign up

Export Citation Format

Share Document