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Transcript of Membrne Reactor- An Innovation in Waste Water Treatment
Membrane Bio-Reactor: An Innovation in Waste Water Treatment
Water Pollution Control (93-530)
August 27th, 2010
Dr. Jian Li
Sepehr Hamzehlouia
Department of Environmental EngineeringUniversity of Windsor, ON
Membrane BioReactor: An Innovation in Waste Water Treatment
Table of Contents
Topic P
Executive Summary ............................................................................................... II
Introduction ................................................................................................................ 1
1. Introduction to Membrane Filtration ..................................................................... 3
2. Introduction to Membrane Bioreactors .................................................................. 4
2.1) Overview of the Technology ................................................................... 4 2.2) Membrane Process Description ............................................................... 5
3. Types of Membrane Bioreactors ............................................................................. 6
3.1) Extractive Membrane Bioreactors (EMBR) ............................................. 6
3.2) Bubble-less Aeration Bioreactors (BABR) ............................................... 9
3.3) Recycle Membrane Bioreactors (RMBR) ................................................ 10
3.4) Membrane Separation Bioreactors (MSBR) ............................................. 11
4. Membrane Filtration Formats .................................................................................. 14
5. Membrane Bioreactor’s Driving Force .................................................................... 16
6. Membrane Bioreactor’s Advantages ........................................................................ 16
7. Membrane Bioreactor’s Business ............................................................................. 20
8. Conclusion ................................................................................................................ 22
9. Reference .................................................................................................................. 23
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Executive Summery
With current extreme shortage of water resources and rapid growth rate of the countries
(specially developing countries) the imminent need to recycling water resources have lead to
technology advance progress in waste water and water treatment field. With the huge amount of
municipal and industrial sewage release to the environment, endeavors to recycle and reuse this
water has raised huge debates between professionals in the field.
Applying the traditional and conventional water treatments methods such as using settling tanks,
primary sedimentation, biological treatment and clarifier step in the typical activated sludge
treatment not only occupies large pieces of land and cycles the water in long circuits but also
doesn't give a convenient water effluent quality result and large amounts of water is still wasted
in the process-line due to inadequate accuracy of the process. As a result of the highly
demanding market, the membrane biological treatment method as an innovative wastewater
treatment process was presented and lots of developments have been done throughout countless
research to optimize the result in both environmental and economical region.
Today, the number of plants concerting from conventional methods to MBR systems in rapidly
increasing and different companies over the globe are investing in developing its applications
efficiency. This article presents a detailed survey over Membrane bioreactor aspects, advantages
and performance.
First the membrane filtration in introduced as a relatively new selective separation process. Then
a detailed introduction over MBR systems with introducing different types and formats of the
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systems are done to clarify various advantages of this new method over the traditional
techniques.
Beyond the sufficiently detailed presentation of Membrane Bioreactor systems as the future of
the water treatment, it is tried to sketch a general overview of Membrane Bioreactors to the
readers.
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Sepehr Hamzehlouia
Dr. Jian Li
Water Pollution Control
August 27, 2010
Membrane BioReactor: An Innovation in Waste Water Treatment
Introduction
When it comes to the water treatment process, the secondary treatment of sewage is in fact a
large and energy intensive process, involving a biological digestion step followed by a sedimen-
tation and settlement of the solid particles caused by the bio-reactions of the “bugs”. The Mem-
brane bioreactor, as an innovative process, replaces the whole secondary stage and acts as a more
efficient replacement in both terms of removal quality and space. MBR acts as a device for the
biological oxidation of the organic materials dissolved in the sewage and separation of these par-
ticles from these particle as a membrane filter which results into slurry of a relatively clean liq-
uid, which in other words, applies an effective membrane filtration process to separate the liquid/
solid phase. The excess suspended solids produced by the biological oxidation process can then
be easily removed for the subsequent treatments. One principle advantage of the MBR process is
its continuous behavior and easily controlled operation which is rapidly introducing the Mem-
brane Bioreactors as the best available technology (BAT) for the wastewater treatment.
When it comes to the process speed rate, the sludge settlement of the conventional secondary
process is a fairly slow step, as a result, the removal of the clear liquid from the slurry is the pri-
mary option which results into a more resolute liquid , at least in the case of applying the Micro-
filtration method. In the case of Ultrafiltration, the effluent flow has a quite clear characteristic as
well.
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Another major advantage of MBR systems over conventional plants is that it can operate at a
much higher suspended solid concentration in the bioreactor vessel in comparison to the tradi-
tional conventional activated sludge plants. As the process experimental data declares, the MBR
plant can work effectively as high MLSS (Mixed Liquor Suspended Solids) concentration in the
range of 8000 to 12,000 mg/L (or in other words 0.8 to 1.2%) and has been successfully per-
formed under up to 3% concentration, where as the conventional activated sludge plant operates
under much lower MLSS concentrations ( in the range of 2000 to 3000 mg/L) due to the settling
limitations. This higher slurry concentration in the case of MBR provides a higher removal effi-
ciency, not only of dissolved organic material but also in the case of residual particle solids.
The high sludge concentration handling ability enables an MBR system to deal more effectively
with heavy industrial wastewater wastes, especially in the places with considerable water short-
age obstacles which forces the industries to employ a closed water cycle throughout their proc-
esses. The MBR system is a relatively recent development in the water treatment applications,
although it has been employed in the wastewater treatment processes for a couple of years. When
it comes to the history of the MBR systems, it was first developed to commercial use in the
United Stated in the late 1970s and later in Japan sewage treatment plants in the early 1980s.
There are now more than 1000 MBR systems under operation worldwide, although a significant
number of plants are only of the pilot scale.
The initial and operating expenses of an MBR plant for secondary treatment processing is still
considerably higher than for a conventional plant, but as number of MBR plants increase in the
business, and as membrane particles costs decrease due to the mass production and demanding
market, the life cycle cost margin will soon disappear and thus, due to the obvious advantages of
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MBR processes over the conventional systems , it should lead to a rapid takeover of the waste-
water treatment industry by the MBR systems. Also, the smaller footprint and construction space
of the MBR plant would eventually make it extremely more attractive for the construction in the
populated urban areas.
1. Introduction to the Membrane Filtration
Membrane is referred to a material capable of forming a thin wall with the ability to transfer dif-
ferent fluids is a selective manner which will ultimately result into the separation of the impuri-
ties. As a result of this capability, membrane should be produced from a material with reasonable
mechanical strength and flexibility with an optimum capacity of selective separation. The me-
chanical structure of a membrane has a firm relationship with the surface porosity of the particles
forming the thin selective separation layer system. The concept of membrane filtration covers a
vast majority of versatile separation systems such as dissolved solutes in liquid streams and gas
mixtures accordingly.
Using membranes as a separation process can be sorted under four main categories:
1) Driving Force: The specific driving force which is used for separation of impurities
that can be listed as temperature , pressure, electrical potential, concentration gradient
and ect.
2) Structural: The structure and the chemical composition of the membrane
3) Separation Mechanism: Microfiltration (MF), Ultrafiltration (UF), Revers Osmosis
(RO) & Nanofiltration (NF)
4) The structural Geometry of the membrane.
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The membrane processes can be also classified by their pressure as the driven process. Microfil-
tration and Ultrafiltration which are sorted as low pressure driven processes, in this process water
is feed through a micro-porous synthetic membrane and divided into permeate. The feed water is
passed through the membrane and the not permitted impurities are rejected to pass and can be
collected accordingly. These membrane processes are most effective for removing microorgan-
isms and particles in the waste water treatment plants. Unlike the first group, Reverse Osmosis is
a high pressure driven process applied for removing salts and low molecular organic and inor-
ganic pollutants. Nanofiltration is the process that operates at a pressure range in between RO
and UF while aiming to remove of divalent ion impurities. Following figure presents the size
range of various pollutants and impurities and the application range of the membrane processes.
2. Introduction to Membrane Bioreactors
2.1) Overview of the Technology
The Membrane Bioreactor (MBR) process is a rapid emerging advanced technology for waste
water treatment which is successfully applied in sewage treatment at a vastly increasing number
in plants around the world. Besides the overwhelming increase in the number , the installation of
MBR systems are also increasing in the terms of scale and capacity throughout the business. The
current operating MBR systems are treating under the capacity of 5-10 ML/d which are pending
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to be replaced by the next generation reactors with 45 ML/d design capacity which is a massive
progress in increasing the process profits and efficiency.
Figure 1 - Membrane Filtration Spectrum
2.2) MBR Process Description
The MBR process is a suspended growth activated sludge system that uses microporous mem-
branes for separating solid - liquid flow systems in lies of secondary clarifiers. As shown for a
typical MBR arrangement in the figure, the design consists of an aeration zone of the bioreactor
followed by and anoxic zone and internal liquid recycle based on modifies Lutzack-Ettinger con-
figuration. In addition to above mentioned design criteria, some plants have used pressure mem-
branes rather than submerged membraned external to the bioreactor.
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In fact, Membrane Biological Reactor technology is a combination of conventional suspended
processes followed by low pressure driven membrane separation processes such as Microfiltra-
tion (MF) or Ultrafiltration (UF) methods. MBR certainly represents one of the most promising
and at the same time effective approaches to the municipal wastewater treatment due to the ad-
vantages such as
1) High compactness
2) Very good quality of effluent
3) Low sludge production
However, the application of some of MBR aspects such as biomass behavior under stressed con-
ditions and fouling controlled should still be evaluated from the both biological and hydraulic
point of view.
3. Types of Membrane Bioreactors
3.1 Extractive Membrane Bioreactors
Extractive Membrane Bioreactors simply known as EMBR increase the biological treatment per-
formance by enhancing the membranes higher selective separation ability by both increasing the
separation and intra-phase transportation of the components. In fact, EMBR supplies the desir-
able condition of optimizing the degradation of the wastewater pollutants by the bioreactor sys-
tem. For example, considering a degradable toxic organic pollutant from the sewage could be
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transferred through a nonporous membrane, resulting a growth bio-medium which should be
degraded. In this case, the driving force of the mass transfer of toxics through the membrane is
the concentration gradient while the bio-medium functions as a sink.
The Extractive Membrane Bioreactor can perform under two different modes:
• Mode 1: In this mode the membrane is immersed in the bio-medium tank. The toxic wastewa-
ter is circulated across the membrane bed and due to the concentration gradient the selective
mass transfer to the surrounding bio-medium is applied. Specific microbial cultures could be
cultivated in the MBR to optimize the degradation of the pollutant from the waste system.
• Mode 2: In this mode, unlike the mode 1 the membrane forms an external circuit with the bio-
medium tank resulting the toxic sewage circulating on the shell side of membrane packs. While
the bio-medium in pumped through the membrane module, do to the concentration gradient,
the selective transfer of pollutants to the bio-medium is occurred. The microorganism applied
in the system is optimized under PH, temperature and dissolved oxygen condition. Ultimately
the biologically treated water is removed on the other side of the membrane shell.
Since the bioreactor is unaffected by the toxic pollutants in the neither of the systems, the condi-
tions could be optimized to increase the degradation efficiency through the system. The EMBR
technology is successfully performed in removing the pollutants such as chloroethanes, chloro-
benzenes, chloroanilines, toluene from the industrial wastewater streams.
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Figure 2.1 & 2.2 - Different Modes of Extractive Membrane Bioreactors
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3.2 Bubble-less Aeration Membrane Bioreactors
In a conventional activated sludge process, the process efficiency is controlled by the availability
of air in the aeration tank, However, due to inefficient air supply methods, 80-90% of the sup-
plied oxygen to the aeration tank is vented back to the atmosphere which affects the system effi-
ciency considerably. Oxygenation using pure oxygen instead of air as the oxygen supply source
results into considerable increase in the overall mass transfer and ultimately biodegradation rate
of the system. However, due to the high power requirements and operational costs of the conven-
tional activated sludge operators which is a result of heavy mixing, these devices are not suitable
to operate with biofilm processes. The advantage of using biofilm process over activated sludge
systems is their ability to retention a higher concentration of the activated bacteria.
The Membrane Aeration Bioreactor simply known as MABR processes use gass permeable
membrane to supply a high purity oxygen resource directly to the biofilm without the ordinary
bubble formation obstacle and is used to transfer large quantity of pure oxygen into the sewage.
Due to the practically diffusion of of the gas through the membrane, a very highly rated air trans-
fer rate in maintained in the system. According to the current researches, the MBR structure is
suggested to be formed as a hollow fibre arrangement with gas and wastewater on the lumen and
shell side of the vessel. The advantage of using hollow fibre modules is their higher surface mass
transfer area for oxygen on the smaller reactor volume simultaneously. In this case, membrane
also acts as a supporting medium for the biofilm formation leading to the reductio in bubble for-
mation and increase in the oxygen transfer rate respectively.
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3.3 Recycle Membrane Bioreactors
The Recycle Membrane Bioreactor’s (aka RMBR) structure consists of a reaction vessel operat-
ing as a stirred mixing tank reactor and an extremely attached membrane module whereas the
substrate sewage and microorganism biocatalyst stream flow to the reactor’s vessel on pre de-
termined concentration bases. Then while mixing in the stirred reactor, the product mixture in
pumped through the external membrane package continuously. Based on the selective permeate
transfer behavior of the membrane circuit, the smaller molecular particles get through the mem-
brane as our degraded end product and the larger sized molecules are deported to the stirred tank
for further processing.
Normally biochemical applications run under batch processes in the industry and due to this fact
the efficiency falls considerably when compared to the continuous processes. One major obstacle
dealing with batch systems is that the microbial species should be separated at the end of each
batch run as the get attached to membrane particles vis adsorption and entrapment during the
treatment process. Unlike the traditional conventional systems, Membrane Recycle Reactors
work under continuous process condition which give them the advantage of maintaining lower
operational costs as the enzymes are utilized more effectively and the effluent is more uniform
and consistent and as the undesired end products are removed continuously from the system, the
biocatalyst poisoning risk will reduce considerably. The disadvantage of using RMBR is the
loose of activity (between 10-90%) due to “enzyme substrate orientation and diffusional resis-
tances.” However the new researches are taking place in the hope of efforts lead to maximizing
the degradation potential of the recycle membrane reactor.
The recycle membrane are utilized under two basic configuration category:
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• Config 1: Beaker Type - In this configuration the substrate alongside the biocatalyst is placed
in a beaker which performs as the reactors vessel tank. The U-shaped bundle of fibers engaged
into the breaker and the product in continuously filtered through the membrane module.
• Config 2: Tubular Type - This type is favored in application on large industrial based scale
where the biocatalyst can be trapped or loaded in the shell or tube side of a tubular membrane
module. I the biocatalyst is trapped inside the membrane tube, then the feed subtrate is pumped
through the shell side of the reactor vessel. Th pumping rate should be controlled to achieve an
optimized resident time for the most desired degradation. This configuration has been tested on
industrial scale for bioremediation activities for the removal of aromatic pollutants and pesti-
cide.
3.4 Membrane Separation Bioreactors
The conventional activated sludge treatment is the most common wastewater treatment method
to treat both industrial and municipal sewage and the major reason behind this fact is its opera-
tional liability. However the effluent quality of this system is highly dependent to the “hydrody-
namic conditions in the sedimentation tank and settling characteristics of the sludge.”As a result
and for getting the most convenient results, large volume sedimentation tanks are used to provide
longer residence time required to obtain the desired solid/liquid separation. Simultaneously, close
monitoring and controlling of the biological treatment unit is strongly recommended to avoid
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condition which could lead to undesirable settle-ability or bulking of the sludge, which at the
same time increases the operational costs.
Application of Membrane Separation methods as a replacement for the sedimentation and bio-
logical steps in a conventional activated sludge treatment plant is a convenient solution to cover
the above mentioned disadvantages. The membrane not only offers a complete shielding barrier
for the suspended solids, but also offers a higher quality in the effluent stream. The idea of cou-
pling an activated sludge process with membrane filtration in the form of UF was first commer-
cialized in the late 1960’s by Dorr-Olivie, but due to lack of enough practical evidence and po-
tential research criteria didn’t attract considerable attention until recent years. But with recent
developments and research results based on membrane separation methods, there has been a con-
siderable increase in application of membrane biological separation techniques in the last ten
years.
The emerging biomass separation bioreactor technology is in fact a combination of “suspended
growth reactor for biodegradation of wastes and membrane filtration” systems. In this method,
the MBR employs filtration modules as effective barriers which the membrane package can be
configure external or immersed to the bioreactor vessel.
The conventional activated sludge processing of the sewage water consists of tertiary treatment
techniques such as carbon adsorption on the biologically treated secondary effluent. First step
toward replacing the traditional system with MBR is replacing the tertiary treatment methods
with an Ultra or Micro Membrane Filtration which guarantees a pollutant free effluent in addi-
tion to a solid removal system without major changes in the current treatment facility and the re-
sult would be a high quality effluent flow.
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The next step is replacing the secondary sedimentation tanks with cross-flow membrane filtra-
tions. In this case, external circuit membranes are applied to increase the biomass circulation rate
over the membrane free surface. As a result of reducing the energy costs for maintaining a higher
velocity, submerged thin layered membranes are employed in the reactors and as a further step to
control the energy consumption in the system, the possibility of using the “jet aeration” in the
reactors was proceeded. The advantage of using the jet aeration method is the energy require-
ments is considerably decreased by using a single pump for both aeration and membrane separa-
tion processes. On recent attempts, using the “air back-washing” technique for membrane de-
clogging led to the innovative approach of using the membrane as both a clarifier and diffuser
simultaneously by its own.
Figure 3 - Developments in Separation Membrane Bioreactors
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4. Membrane Filtration Formats
There are two sort of membrane format applied in the MBR technology:
• Format 1: The Kubota Format - Developed by Kubota, they use flat rectangular plates of
membrane, attached (welded) around a panel for each pair located in a vertical and parallel po-
sition to other pairs on either side of the panels. Spacer sheets are located in the free space be-
tween the membrane plates and the support panel which allows the permit to run through the
membrane to a withdrawal nozzle on the top of the cartridge. Liquid flows in an external cir-
cuit to the center of the cartridge.
• Format 2: The Zenon Format - Developed by Zenon uses a vertical formation of hollow fibers
to create the membrane module which lets the flow run in an external circuit to the center of
the fibers. The end of each fiber is sealed firmly and the heads are altogether capped to a per-
meate off-take chamber. The hollow fiber has the capability to handle the low transmembrane
pressure in the MRB process but most manufacturers recommend using reinforced fibers as a
more trustable option.
Both Formats can be used for submerged or side-stream operations.
Beside the two main formats there are also two less recognized formats performing in the indus-
try:
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• Format 3: Capillary Tubes Membrane - This format is mostly used for side-stream filtration,
where the flow goes through and internal circuit across the fibers and exits into a permeate col-
lection chamber. The disadvantage of using this method is that, due to the through-flow mode
operation, the separated sludge in accumulated inside the tubes, thus there should be regular
backwash interval applied to prevent clogging. On the other hand, the flat sheet and hollow fi-
ber membranes operate in an approximation to cross-flow and an air-scour operation is used to
flush out the solids out of the membrane surface.
• Format 4: Circular Disc Membrane: In this format the membranes are shaped in circular disc
form located on a horizontal shaft. The whole array is submerged in the activated sludge sus-
pension and the disks are rotating on a constant angular speed. The permeate flow is from an
external circuit of double-sheet disks and in to the central shaft which is hollow shaped to let
the permeate off-take flow through.
Independent from the selected format, an air scouring is used to remove the solids from the
membrane surface which can be supplied from the same air flow used to activate the solid sus-
pension although the injection systems are allocated separately. Hence, the elimination of the set-
tling chambers leeds to a smaller volume reaction tank which makes the MBR system easier to
install in the plant area.
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5. Membrane Bioreactor’s Driving Force
In most cases, membrane filtration processes require a high transmembrane pressure to maintain
acquired flow rate. On the other hand, the bioreactors perform with a low pressure differential of
approximately 0.5 bars. This pressure is provided by a operating pump and specifically a vacuum
type on the permeate discharge line.
The MBR usually operates by ultrafiltration, but in the case that a specific degree of separation
ins required, microfiltration membranes are installed on the system.
A normal MBR system has a capacity of removing SS to below 5 ppm and BOD to 10 ppm
which is by a large margin under current wastewater standards. By selecting an appropriate de-
sign criteria, the removal of chlorine resistant pathogens such as Cryptosporidium and Giarada
and also nitrogen and phosphorus compounds would be available.
6. Membrane Bio Reactor’s Advantages
The Advantages of using MBR over conventional methods are listed as below
• Total Elimination of Suspended Solids: Since the suspended solids are completely eliminated
from the sludge stream through the membrane filtration, the settle-ability of the sludge which is
a problem while performing conventional activated sludge process does not affect the effluent
quality and as a result the system is operated and maintained easier.
• Longer Sludge Retention Time: As Sludge retention time (SRT) is independent of Hydraulic
retention time (HRT) therefore, a longer SRT could be maintained leading to a complete reten-
tion of slow growing microorganisms such as nitrifying bacteria, through the process.
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• Higher Overall Activity Level: Using MBR systems makes it possible to maintain higher con-
centration in bioreactors and simultaneously disperse the microorganisms on a desirable time
base without concerning about extra volume. In addition, due to elimination of sedimentation
and post-treatment equipments, there would be a reasonable space reduction in the plant de-
sign.
• Improved Treatment Efficiency: By preventing the leakage of un-decomposed polymer sub-
stances, the treatment efficiency is improved considerably. In case of being degradable, there
could be no pollutant accumulation through the system and also provides the ability to prevent
smaller molecular compounds to pass the membrane filter without being treated by break down
and gasification by microorganisms or conversion to polymer chains. This capability increases
the effluent water quality.
• Ecological Friendly: Removing the bacteria and viruses from the sludge flow makes the disin-
fection process ecological friendly.
• Lower Food to Microorganism Ratio: When compared to the conventional activated sludge
processing plants , MBR maintains lower F:M ratio which results into less excess sludge to be
treated.
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• High Sludge Capacity: As the fluctuations over volumetric loading has no effect on the system
performance a higher sludge capacity would be maintained.
• Odorless: due to the tight structure of the system there is absolutely no risk of odor dispersion
throughout the system.
• Reduced Footprint: As Secondary Clarifier and Tertiary Filtration steps are eliminated there
would be a considerable reduction in the plant footprint. Furthermore, under special conditions
other processing units such as digesters or UV disinfection can also be eliminated (or mini-
mized) to provide a more reduced footprint.
• Reduced Aeration Tank: Since in MBR systems the solid separation quality is independent
from MLSS concentration, therefor, since the elevated mixed liquor concentrations are possible
the aeration basin volume is reduced leading to further reduction in the plant footprint.
• Sludge Characteristics: Since there is no reliance upon achieving quality sludge settle-ability,
therefore it is quite amenable to remote the operation. In addition, MBR systems can be de-
signed with longer sludge age and lower sludge production at the same time.
• MF/UF Quality Effluent: This ability makes the effluent water available as a quality fee for the
Reverse Osmosis treatment. This MF/UF specification criteria includes SS<1 mg/L,
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Turbidity<0.2 NTU and up to 4 log removal of the viruses. In addition, this MF/UF provides a
barrier to chlorine resistant pathogens such as Giardia and Cryptosporidium.
• No Odor, Noise or Visual Amenity: The foot print reduction solves the visual amenity, noise and
odor problems. Due to the compact plant structural area, the buffer distance with the closest
habitable neighborhood is decreased, hence the land value in the area increases reasonably.
• Cost Comparison: When it comes to cost comparison between MBR systems and the conven-
tional treatment solutions, the results may reveal a reasonably comparable initial and opera-
tional cost of the MBR versus the traditional systems, significantly when the land value is con-
sidered in the initial design. In addition, due to the increase in the labor costs and inflation and
at the same time reduction in membrane value due to mass production and the demanding mar-
ket, when the capitol costs are estimated, there is a considerable likelihood of MBR becoming
the favorite solution in the coming years. Furthermore, plant designers are advised to estimate
the capitol and operating costs of the emerging technology on the timely basis.
The following table is maintained as a result of the MBR process performance in Japan and is
presenting the overall performance of immersed type MBR systems in term of influent and efflu-
ent concentrations which leads to a reasonable overview of the MBR performance characteris-
tics. Considering the water treatment standard of Japan, the results fully comply with the stan-
dard regulations. It it also mentionable and the reactor performance wasn’t affected under change
of various operating conditions which leads to the fact that improvements in the membrane flux
MBR : An Innovation in WW Treatment Hamzehlouia 19
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does not affect the effluent water quality even at a short hydraulic time as 3 hours, thus reducing
the size of the treatment unit. The effectiveness of the hypothesis was proven since neither of the
effluent turbidity or pathogen level was reported below the japanese drinking water standard cri-
teria. Under specific demands, a small dosage of chlorine could be added to maintain a residual
chlorine concentration in the drinking water distribution system.
Table 1 - Comparison of reclaimed water quality of the MBR with reuses guidelines
7. Membrane Bioreactor Business
The MBR is already on the verge of conquering the municipal wastewater treatment industry
which covers a major part of water treatment activity over the world. The water treatment con-
tractors plan their systems based on the more effective and economical technology and as a result
there is a demanding market of new technology equipment manufacturers.
The MBR as an effective treatment process can definitely be found on the manufacturers produc-
tion list specially by the secondary treatment process specialists with membrane technology ap-
MBR : An Innovation in WW Treatment Hamzehlouia 20
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plication of the membrane system manufacturers with a foresight in the wastewater business. The
primary developers of MBR system were Zenon in Canada and Kubota in Japan which where the
pioneers in manufacturing the new systems and were closely followed with the German competi-
tors Wehrle Werk. In a recent estimation, there approximately 30 MBR manufacturers active
worldwide which the successful ones include Zenon, Kubata, USFilter and Mitsubishi Rayon.
There are various MBR systems currently installed or are under construction around the globe
which Zenon has manufactured several hundreds of them and Kubata and Mitsubishi Rayon have
installed 2500 and 700 systems mostly in Japan. The largest MBR plant is constructed and sup-
plied by Zenon in Brightwater plant in King County, Washington State with an initial capacity of
495 Megaliters per day when completed in 2011 which the capacity will be increased through the
time to approximate 645 Megaliters per day by 2040.
Figure 5 - Brightwater Plant, King County, Washington State
MBR : An Innovation in WW Treatment Hamzehlouia 21
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8. Conclusion
The global industry is directed into using MBR systems due to their decline membrane costs and
increasing demand for water resources has leaded to considerable increase in application of
MBR systems in the water treatment industry. With recent developments on the matter, an even
more demanding market for Membrane Bioreactors are expected in the near future considering
their major advantages over the conventional systems.
With various researches still continued over optimizing MBR process application results and ef-
ficiency, more advanced and economically reasonable systems could be designed and manufac-
tured for industrial coverage in the coming years.
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[11] IMMERSED MEMBRANE BIOREACTOR PERFORMANCE EVALUATION: TWELVE
PINES SEWAGE TREATMENT PLANT SUFFOLK COUNTY, NEW YORK, (2004). FINAL
REPORT 04 -04
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