mbr-c1 fundamentals of mbr

7/21/2019 MBR-C1 Fundamentals of MBR

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MBR CourseFundamental of MBR Processes &Introduction to Process Design Tools

October 16 & 17, 2012

Hamid Rabie


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Function of a WWTP

Removal of particulate materials

sand hairs, fibrous materials

other solids

Biodegradation of undesired components

Solid liquid separation

WWTPEffluent

Surplus sludge (biomass)

Wastewater

phosphorus biomass

carbon

nitrogen

sulphur

CO2 + biomassN2 + biomass

biomass

Microbial rejection

biomass rejection

standard sedimentation: 10,000 CFU/ml(colony forming unit: cfu)


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Solid - Liquid

Separation

Biological Process

Fundamentals of Bio-Reactor Processes

Wastewater Effluent

SludgeEngineered systems to:

Accumulate microorganisms for oxidation of electron donor pollutants.

Convert soluble pollutants to large particles (biomass) for separation.

Settling Filter media Membrane


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Fundamentals of Bio-Reactor Processes

Aerobic

Anoxic Aerobic

Anaerobic Anoxic Aerobic

Pollutant Measurement Biological Reaction Process Name Condition

Carbonaceous BOD, COD cellsCOOrganic O

+ 22 BOD Removal Aerobic

Ammonia N - NH3 cellsNONH O + 332 Nitrification Aerobic

Nitrate TNcellsNNO

+

23

Denitrification Anoxic

Phosphorous TP cellsP Bio-P Removal Anaerobic

BOD / Nit

BOD / Nit / Denit

BOD / Nit / Denit

Bio-P


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First Use of Membranes in Biological WWT

SGFPCBS

= Step screen= Grid and fat removal= Primary clarifier= Biological step

STDCMT

= Sedimentation tank= Third cleaning step (e.g. filtration)= Membrane technology

Effluent treatment with membrane technology tertiary treatment

Raw

wastewater

Effluent

S GF PC ST DCBS MT Permeate


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Membranes at the End of WWT Process

Always end of the processes

Tertiary treatment

Almost similar to surface water treatment (need for coagulant)

Low solid concentrationtolerance in membrane stage

Mostly dead end filtration mode

Sensitive against foulingcomponents

Interesting for existing WWTP that need disinfection or reuse

additional costs to conventional technology;additional footprint required

no hair and fibrous material allowedrequires easy sludge management

Pressurized membrane systems or

Submerged membrane systems

fouling components come in direct contactwith membrane surfaces;often additional flocculation required;operation difficult to optimize


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Raw

wastewater

S

Effluent

TCPC BS STGF

Changes in the MBR System

S

GFFSBS

= Step screen

= Grid and fat removal= Fine screen= Biological step

MT = Membrane technology

Membrane bioreactor (MBR)

BSFS MT

Permeate

Combination ofbiological stepand solid liquidseparation


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MBR vs. Conventional Activated Sludge

Pre-TreatmentIncomingWastewater Effluent

AnoxicZone

AerobicZone

SettlingTank

RAS

Conventional Activated Sludge SystemConventional Activated Sludge System

Pre-TreatmentIncomingWastewater

AnoxicZone

AerobicZone

RAS

Membrane Bioreactor (MBR)Membrane Bioreactor (MBR)

EffluentMF/UF

In case of TertiaryMore processes;

e.g. sand filter


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MBR Reduces the Footprint

Membranes

Eliminate all clarifiers

Replace withmembrane systems


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Major Differentiations of MBR Technology

Activated

SludgeProcess

Membrane

FiltrationMBR

Stable

Biological

Treatment

Process

Absolute

SolidsSeparation

Replaces conventional clarification; requires less footprint

Combines physical barrier of a membrane with biological treatment

Produces high quality effluent at all times Comparable to tertiary treatment; then LCC is conventional technologies

membranekey component to this market


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Better effluent quality> 95%, 98% and 99.9% for COD,BOD, SS removal

Effluent TSS independent of

bioreactor efficiency

High MW organics are retained andbio-degraded

Improved biological reactions (dueto longer SRT, shear, etc.)

Process ControlComplete separation between HRTand SRT

Accurate control over sludge age,development of slow-growing

microorganisms (nitrifiers)

Increased EfficiencyAll bacteria retained, cold weathernitrification

Insoluble P retained reducing

chemical addition for P removal

High MLSS (1-2%), greater organicloads and less sludge production

Compact systems, less footprint

Sludge digestion within bioreactor

Modular expansion

Absorbs variation and fluctuations inincoming flow and organic loads

Advantages of MBR over Conventional


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Market Areas for MBR Technology

MembraneBioreactors

leachate

municipalwastewater textile

industry

industriallaundries

pulp &paper

tank

cleaning

beverageindustry

dairyindustry

vegetableindustry

fruitindustry

Slaughter-house /

rendering

petrochemindustry

chemicalindustry

pharmacy

industry

High ammoniacontent

High CODcontent

High CODcontent

High & variablesalt content

Space limitation

reuse; high quality

High &variable salt

content


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Increasing regulatory standards

especially regarding disinfectant by-

products and waterborne pathogens

Limited supply

tap into alternative supplies

such as water re-use

Growing demand

due to population growth, newinfrastructure in developed

countries, and aging infrastructure

in industrialized countries

Technological innovation

development of low cost,

high quality water treatment

solutions

Growth inMembrane

Technology

Drivers of MBR Market & Technology


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Hollow fiber modules Plate modules

GE-Zenon

Mitsubishi

Siemens-Memcor

Koch Membrane-Puron

Micronet PF

Kubota

Toray

Huber

A3 Gmbh

Tubular modules

Outside/In FiltrationImmersed (Vacuum)

Outside/In FiltrationImmersed (Vacuum)

Inside/Out Filtration(Pressurized Vessel)

Main Configurations for MBR Technology

X-Flow / Pentair

Berghof

Koch Membrane


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modules cross flow operation

MBR with Tubular Modules -Cross Flow Membrane Filtration

External cross flow MBR

RCRL

MFDN N

RCRL

MFNDN

recirculationreturn line

membrane filterNitrificationDe-nitrification

PressurePump

Module Length

Pressure

Feed side

Permeate side


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Cross Flow Membrane Filtration for MBR Tubular Membrane (Inside/Out Filtration)

Membrane

Support Material

Feed

(Clean Water)

Permeate

Concentrated

Waste


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Cross Flow Membrane Filtration for MBR Tubular Membrane

Original work-horse in MBR applications; used horizontal configuration

Large diameter membrane tube and high recirculation flow rate and high

TMP served to eliminate potential for plugging with biomass Membrane designed to operate at MLVSS levels > 50,000 mg/l

Energy intensive on large flow rates (> 300,000 gpd)

Low packing density (requires large footprint for large flow rates) New tubular systems from X-Flow uses air plugs in vertical tubes

operating at lower pressures


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Tubular MBR Configurations

MLSS: 12-50 g/L

Flux: 50-150 lmh

High energy consumption:

(1.5-4.0 kWh/m3)

Continuous

TMP: 1.0-5.0 bar

MLSS: 8.0-12 g/L

Flux: 30-50 lmh

Lower energy consumption:

(0.3-1.0 kWh/m3)

Discontinuous

TMP: 0.2-0.6 bar

More valves & complexity

X-Flow Airlift


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Waste water

Air

MBR with Submerged (Immersed) membranes

Biological sludge

Vacuum Pump

Permeate

submergedmembranes


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Basic of Immersed MBR Train

1.Biological reactor

2.Membranes

3.Permeate pump & blower

4. Control panel

5. Permeate & air piping

1

2

43

5


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Immersed Membrane Filtration (hollow fiber)

Membrane

Coarse Bubble

Diffuser

Permeate to Top Header

(Puron has no top header)Support Material

(e.g. Zenon, MPF, Puron)

Permeate to Bottom Header(Siemens has no bottom header)

Bulk Fluid

(Concentrate)

Aeration

Bubbles (forfluid agitation)

Coarse Bubble

Diffuser

Outside/In Filtration

S

uction


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Immersed Hollow Fibers in Operation

Module Installationwith crane

Submerged module in operationair injection phase


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Immersed Membrane Filtration (flat sheet)

Air bubbles between

membrane panelsAir diffusers

Suction

To suction

Panel


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MBR with submerged modules -different tank configurations

Internal submerged MBR

RC

MFDN N

RCRL

MFNDN

recirculationreturn line

membrane filterNitrificationdnitrification

External submerged MBR (Preferred)

RCRL

DN N MF


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Key Aspects of MBR Products

Membrane structure and characteristics

For superior technological and economical performance, should consider:

Module design and features

Membrane tank hydraulics

Membrane filtration process and system design

Aeration system & sludge management


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Classification of membrane processes

Nano-filtration

RO

1

10

100

Pressuredifference

in

[bar]

VirusesBacteria

Saline solutions

0,1

Particle size in [m]

0,1 1,0 10,00,010,0010,0001 100

Sandfiltration

Microfiltration

Ultrafiltration

Membrane pore size range from

different suppliers for MBR


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Comparison of microorganisms vsmembrane pore size

poresize ~ 0,01 m

ultrafiltration

poresize ~ 0,2 m

microfiltration

E. Coli ~ 0,5 - 1,5 m

MS2-Virus (Coliphage)

~ 0,025 m

B. Subtilis~ 0,3 m


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MBR provides better effluent quality

Parameter MBRconvent.

plant

Solids mg/l 0 10 15

COD mg/l < 30 40 50

Ptotal withprecipitation

mg/l < 0,3 0,8 1,0

MLSS content inaeration tank

g/l < 20 < 5


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Key Requirements for Membrane Properties

hydrophilicity - good wetability with water

low fouling tendency

chemical and thermal stability

Material requirements

mechanical stability

narrow pore distribution

minimized number of defects

high porosity

low hydraulic resistance

high bonding of membrane to support material

Morphological requirements

cost-effective materials

cost-effective production

Economic requirements

Diff t T f M b & St t


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Different Types of Membranes & Structures(SEM of Membrane Surfaces)

Mitsubishi

2 m2 m

KubotaToray

3 m2 m

Zenon

Avg. Pore: 0.03 m

PVDF low MW

Asymmetric

Coated on a support

Avg. Pore: 0.1 m

PVDF high MW

Asymmetric

Coated on fabric

Avg. Pore: 0.4 m

Chlorinated PE

Symmetric

Coated on fabric

Avg. Pore: 0.2 m

PVDF low MW

Asymmetric

Double coating

Coated on support10 m

Asymmetric Structure

Membrane Skin/Surface


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Introduction to DesignTools


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Key Elements of MBR Process Design

Full step by step biological reaction analysis and mass balances such as:

Carbon, Phosphorous, Nitrogen, etc

Sludge production

Aeration and nutrient requirements

Step by step process mass balances and all necessary sizing such as:

Pumping and coarse screen

Sand and fat removal Fine screen

Equalization

All dosing systems

Different biological steps

Sludge treatment

Membrane systems: filtration tank, configuration, RAS, sludge g=feed,aeration capacity, blower sizes, pump sizes, chemical dosing, etc


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System Configuration


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Step by Step Process Calculations

S b S P C l l i


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Step by Step Process Calculations

Process Trends for Different Key Parameters


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Process Trends for Different Key Parameters

mbr-c1 fundamentals of mbr

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