membrane bio reactor - reza...

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Presenter: Javad Saadati

Supervisor: Dr. Gheshlaghi

Ferdowsi University of MashhadChemical Engineering Department

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Contents

Introduction

Membrane fundamentals

Membrane Bioreactor Systems

Applications

Conclusion

References

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Introduction

A membrane is defined as a material thatforms a thin wall capable of selectively resistingthe transfer of different constituents of a fluidand thus effecting a separation, of theconstituents [1].

For many processes the membrane acts in away to reject the pollutants, which may besuspended or dissolved and allow the “purified”water through it.

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Membranes can be classified by [1]:

1) the driving force used for the separation ofimpurities, such as pressure, temperature,concentration gradient, partial pressure,electrical potential etc;

2) the structure and chemical composition,

3) the mechanism of separation and

4) the construction geometry of themembrane.

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There are six commercially used membraneseparation processes [2]:

Microfiltration (MF)

Ultrafiltration (UF)

Nanofiltration (NF)

Reverse Osmosis (RO)

Dialysis

Electrodialysis (ED)

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o Microfiltration (MF) and ultrafiltration (UF) are low

pressure driven processes.

o Reverse osmosis (RO) is a high pressure driven process

designed to remove salts and low molecular organic and

inorganic pollutants.

o Nanofiltration (NF) operates at a pressure range in

between RO & UF targeting removal of divalent ion

impurities [1].

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Membrane Materials:

Organic polymer

Ceramic

*All of commercial MBR manufacturers use polymeric

MF membranes.

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Polymer Membranes:

Low cost production

Natural variations in pore size

Prone to fouling and degradation

Ceramic Membranes:

Excellent quality and durability

Economically unfeasible for large operations

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The most common types of MBR are hollow fiber

and plate and frame.

Hollow fiber membranes are extruded into long

fibers and joined into bundles, called modules.

The modules are submerged in the wastewater

and permeate is drawn into center of the fiber by

an applied vacuum.

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Plate and frame modules are made from large

membrane sheets loaded into cassettes.

Permeate is drawn through the membrane

due to an applied pressure differential.

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Membrane Bioreactor (MBR) systems

essentially consists of combination of

membrane and biological reactor systems.

These systems are the emerging technologies,

currently developed for a variety of advanced

wastewater treatment processes.

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In general, MBR applications for wastewater

treatment can be classified into four groups,

namely:

I. Extractive Membrane Reactors

II. Bubble-less Aeration Membrane Bioreactors

III. Recycle Membrane Reactors

IV. Membrane Separation Reactors

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Extractive Membrane Reactors

Extractive membrane bioreactors (EMBR) enhance

the performance capabilities of biological treatment of

wastewater by exploiting the membrane’s ability to

achieve a high degree of separation.

This separation aids in maintaining optimal

conditions within the bioreactor for the biological

degradation of wastewater pollutants.

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Bubble-less Aeration Membrane Bioreactors

In a conventional aerobic wastewater treatment unit

such as an activated sludge process, the process

efficiency is controlled by the availability of air.

Due to inefficient mode of air supply, 80-90% of the

oxygen diffused as air in an activated sludge process is

vented to the atmosphere.

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Bubble-less Aeration Membrane Bioreactors

The membrane aeration bioreactor (MABR) process use

gas permeable membranes to directly supply high purity

oxygen without bubble formation to a biofilm.

As the gas is practically diffuse through the membrane,

very high air transfer rate is attained.

The membrane also acts as a support medium for the

biofilm formation, which reduces the potential for bubble

formation and air transfer rate.

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Recycle Membrane Bioreactors

The membrane recycle bioreactor consists of a

reaction vessel operated as a stirred tank reactor and

an externally attached membrane module.

The substrate (feed wastewater) and biocatalyst are

added to the reaction vessel in pre-determined

concentrations. Thereafter the mixture is continuously

pumped through the external membrane circuit.

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Recycle Membrane Bioreactors

The smaller molecular compounds, the end products

of the biodegradation reaction, are permeated through

the membrane.

While the large molecular size biocatalyst are

rejected and recycled back into the reaction tank.

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Membrane Separation Bioreactors Application of membrane separation (micro or ultra filtration)

techniques for biosolid separation in a conventional activated

sludge process can overcome the disadvantages of the

sedimentation and biological treatment steps.

The membrane offers a complete barrier to suspended solids

and yields higher quality effluent.

In this system, the solid-liquid membrane separation

bioreactor employs filtration modules as effective barriers.

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Applications

MBR treatment is applicable to many sectors, including:

Municipal

Industrial

Water reclamation

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Conclusion

The application of MBR technology is rapidly expanding,

with new installation occurring every year.

MBR technology is highly suited for the reclamation of

waste water due to the ability to produce drinking water

quality effluent.

The small foot print and ease of operation of the MBR

system makes it ideal for application in remote areas where

waste water can be reused for irr

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References

[1] C. Visvanathan, R. Ben Aim. Membrane Bioreactor

Applications in Wastewater Treatment

[2] Stacy Scott, Application of membrane bioreactor technology

to waste water treatment and reuse.

[3] Neha Gupta, N Jana, submerged membrane bioreactor

system for municipal waste water treatment process: an

overview, Indian journal of chemical technology, Vol. 15, pp. 604-

612.

membrane bio reactor - reza...

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