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BUILDING A WORLD OF DIFFERENCE®

IFAS and MBBR Webcast March 18, 2010

Process and Practical Design Process and Practical Design Considerations for the IFAS Considerations for the IFAS

and MBBR Technologies and MBBR Technologies

Mark Steichen, P.E.

Heather M. Phillips, P.E.

Slide - 2 IFAS and MBBR Webcast March 18, 2010

Agenda

� Overview of IFAS/MBBR

� Process Design Considerations

� Practical Design Considerations

� Applications in North America

� Questions & Answers


IFAS and MBBR - What’s the difference?

� Includes Return Activated Sludge (RAS)

� Fixed film & Suspended growth

� No RAS - “Once through”process

� Fixed film Only

IFAS (Integrated Fixed

Film Activated Sludge)

MBBR (Moving Bed

Bioreactor)

Waste Activated Sludge

Return Activated Sludge

Waste Sludge


The IFAS Advantage(Comparative Nitrification Upgrade Example)

Conventional IFAS

Expanded

Aeration

Modified

Existing

Aeration

Existing

Aeration

Suspended Growth OnlySuspended and

Attached Growth


Anoxic Zone

Mixers

Equipment Components

MediaAeration equipment

Media retention sieves


Free-Floating Media Manufacturers

Kruger / AnoxKaldnes

Lotepro Linpor Siemens / AGAR

Headworks (Hydroxyl)


Life Cycle Cost Analysis (Activated sludge Nit/Denit Upgrade)

$0

$10

$20

$30

$40

$50

$60

$70

$80

Conventional IFAS Step-Feed MBR BAF

Mil

lio

ns

Process Option

NP

V C

os

t

O&M

Construction

Equipment


Drivers for use of IFAS and MBBR

MBBR

� Severe site constraints or restrictions requiring footprint advantage of the MBBR/HRC process configuration

� Post nitrification and denitrification MBBR applications

� Client preference – some clients have a preference for fixed film and are concerned with operational complexity of activated sludge, or IFAS

� Upgrade of trickling filter or RBC plants that have poor final clarifiers

� Resiliency to peak wet weather flows - very low MLSS of 200 to 300 mg/L

IFAS

� Site constraints or restriction

� Upgrade of existing activated sludge for N&P removal

� FC are designed for high SLR

� Volume limitations require both suspended and fixed film inventory

� Must meet stringent NH3-N limit

� Can integrate with Bio-P

� Resiliency to peak wet weather flows due to lower MLSS and SLR

Waste Activated Sludge

IFAS

Return Activated Sludge

Waste Sludge

MBBR HRC/DAF



Process Design Considerations

Process Design Considerations


IFAS Process Configurations

AX

MLR

RAS

Two-Stage Nitrogen Removal

OX Media

OX Media

OX Media

Carbon Supplementation

OX MediaAX

MLR

RAS

Four-Stage Nitrogen Removal

2nd AXMedia

OXOX

MediaOX

MediaOX

Media

OX Media

RAS

Nitrification

OX Media

OX Media

2 or 3 OX cells in series

� Higher kinetic rates

� Optimum DO control

� Avoid media migration

AN

IFAS is Compatible

with Bio-P


Optimized IFAS MLE Configuration

� Three oxic cells in series to increase efficiency

� Ox1 - suspended growth zone for BOD removal

� DO of 2.0 mg/L

� Ox2 – media zone for nitrification

� DO of 4.0 mg/L to increase biofilm nitrification rate

� best bang-for-media $

� Ox3 – suspended growth polishing zone

� DO of 1.0 mg/L

� Deplete oxygen for internal recycle

Ox1BOD Rem.

DO=2.0mg/L

Ox2Media Nitr.

DO=4.0mg/L

Ox3PolishDO=

1.0mg/L

AX

MLR

RAS


MBBR Process Configurations

� Industrial Pretreatment

� Reduce COD load

� Remove toxic compounds that could inhibit nitrification

AB

OX Media

RAS

Industrial Pretreatment MBBRIndustrialLoad

OX Media

Nitrification MBBR

OX Media

AB

RAS

High Rate ASPost Nitrification MBBR

OX Media

HRCDAF

Actiflo/DensadegCloth filter

� Nitrification

� Activated sludge upgrade

� Post nitrification and/or denitrification


MBBR Process Configurations (Cont.)

� Denitrification

� Two-stage

� Four-stage

� Not compatible with Bio-p

AXMedia

Internal Recycle

Two-Stage MBBR

OX Media

OX Media

OX Media

Waste Sludge

OX Media

AXMedia

Internal Recycle

Four-Stage MBBR

2nd AXMedia

OX

Carbon Supplementation

AN

Waste Sludge


Nutrient Removal Check List

� BOD Removal

� Biomass

� Air

� Time

� Nitrification

� Biomass

� Air

� More Time

� Alkalinity

� Denitrification

� Biomass

� No Air

� Time

� Soluble BOD

� Biological Phosphorus Removal

� Biomass (Phosphorus Accumulating Biomass)

� Time

� Soluble BOD (as VFA)

� Cycles of Air, No Air – IFAS ONLY (currently)


Broomfield WWRF (Colorado)

� Phase 1 (8 mgd) - online in 2003, exceeded design expectations

� Phase 2 (12 mgd) – under construction

� Reduced media fill fraction from 48% to 30%

� Reduced number of blowers from 3 to 2

Mixed Liquor Recycle

Mixed Liquor Recycle

RAS fromClarifiers

To Secondary Clarifiers

Primary Effluent

FEQ Return

Anaerobic Anoxic

Oxic with Media


Biomass Quantification(gTSS/m2 media surface area)

2nd Anoxic1st Anoxic

1st Oxic2nd Oxic

6 g/m2

9 g/m2

28 g/m2 13 g/m2

South Adams County MBBR


Broomfield – Seasonal Attached Biomass

0

1,000

2,000

3,000

4,000

5,000

6,000

1/1

/04

4/1

/04

7/1

/04

9/3

0/0

4

12

/30

/04

3/3

1/0

5

6/3

0/0

5

9/2

9/0

5

12

/29

/05

3/3

0/0

6

6/2

9/0

6

9/2

8/0

6

12

/28

/06

ML

SS

(m

gT

SS

/L)

0

5

10

15

20

25

30

Eff

lue

nt

Am

mo

nia

(m

gN

/L)

Te

mp

era

ture

(ºC

)

Att

ac

he

d B

iom

as

s (

gT

SS

/m2)

Temperature

MLSS

Attached Biomass,First Zone in Series (Oxic)

Attached Biomass,Second Zone in Series (Oxic)

Effluent Ammonia


Basic Design Parameters

� Biofilms

� Hydraulic Retention Time

� Surface Area Loading Rate

� BOD

� Nitrogen

� Activated Sludge

� Hydraulic Retention Time

� Solids Retention Time

� Integrated Fixed Film Activated Sludge

� Combination of both


Moving Bed Biofilm Reactors

� Just like trickling filters, ammonia removal is a function of the BOD loading rate.

� Ammonia concentrations at South Adams County:

Anoxic

Anoxic

OxicOxic Oxic

Oxic

Anoxic

Anoxic

Nitrate Recycle

Primary Effluent ~30 mg/L

To Clarifiers

Media in the Basins

Anoxic 1: ~12 mg/L

Anoxic 2: ~11 mg/L

Oxic 1: ~11 mg/L

Oxic 2: < 5 mg/L


Surface Area Loading Rate vs. Removal Rate

0.00

0.25

0.50

0.75

1.00

1.25

1.50

0.00 0.25 0.50 0.75 1.00 1.25 1.50

Specific Ammonia Loading Rate (gN/m2/day)

Sp

ecif

ic A

mm

on

ia R

em

ova

l R

ate

(g

N/m

2/d

ay

)

100%

80%


The Effect of BOD Loading on Effluent Ammonia

0

5

10

15

20

25

30

35

4012

/19

/03

03

/18

/04

06

/16

/04

09

/14

/04

12

/13

/04

03

/13

/05

06

/11

/05

09

/09

/05

12

/08

/05

03

/08

/06

06

/06

/06

09

/04

/06

12

/03

/06

03

/03

/07

06

/01

/07

08

/30

/07

11

/28

/07

02

/26

/08

05

/26

/08

08

/24

/08

11

/22

/08

02

/20

/09

05

/21

/09

08

/19

/09

Pla

nt

Eff

lue

nt

Am

mo

nia

(m

g-N

/L)

MB

BR

Tem

pera

ture

(C

)

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

Sp

ec

ific

Am

mo

nia

Lo

ad

ing

Rate

(g

N/m

2/d

)

Ap

pro

x.

Sp

ec

ific

BO

D L

oad

ing

Rate

(g

O2/m

2/d

)

Temperature Specific Ammonia Loading Rate

Approx Specific BOD Loading Rate Effluent Ammonia (7-d avg)

Biotower

in Series

with

MBBR

Bio

tow

er

Para

lle

l

to M

BB

R Biotower Offline

(All Flow to MBBR)

Seasonal ammonia limits: 10 – 24 mg/L, or Report


The Effect of Dissolved Oxygen Concentration

Org

anic

load

= 0

,0 g

BO

D/m

2 d

0,0

1

2

3

4

5

6

7

0,5

1,0

1,5

2,0

2,5

0 2 4 6 8 10

Oxygen concentration (mg 02/l)

Am

mon

ia r

emov

al

rate

(g

NH

4/m

2/d

)

Me

dia

Su

rfa

ce

Boundary Layer

Bulk Liquid

Gas Layer

BiofilmLayers

Streamer

Source: 2007 IWA/WEF Nutrient Removal Specialty Conference, Worskhop B (AnoxKaldnes)


DO Sensitivity

y = 60.222x-2.4082

R2 = 0.9715

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0

11.0

12.0

0 1 2 3 4 5 6 7 8 9 10 11 12

DO, mg/L

Eff

luen

t A

mm

on

ia,

mg

/LResidual DO vs. biofilm nitrification

Fort Myers, FL – MBBR

Process Model Simulation


Modeling a Biofilm SystemM

ed

ia S

urf

ace

Boundary Layer

Bulk Liquid

BiofilmLayers

Streamer

Gas bubbles

Solids attaching

and detaching

� Maximum biofilmthickness

� Biomass per unit surface area

� Inert content of biofilm

� Nitrification and denitrification rates

� Attachment and detachment rates

� How do these vary in each zone?


Commercial Simulators

� BioWin

� GPS-X

� West

� Aquifas

� Others

� But models must be

calibrated to site-specific conditions.

GPS-X (Hydromantis)

BioWin (Envirosim)


Demonstration, Pilot and Bench Studies

� Demonstration

� Configure one or more treatment trains and monitor full-scale performance.

� Pilot

� Design a small-scale system to mimic full-scale performance, using plant wastewater.

� Bench

� Smaller, lab-scale


Designing a Pilot System

� Allow adequate startup time – biofilm systems can take several weeks to reach steady state.

� Mimic design conditions:

� Coldest temperature (nitrification, denitrification).

� Warmest temperature (if oxygen transfer is a concern).

� Flow and loading conditions.

� Dissolved oxygen concentrations.

� Chemical doses.

� Mixing intensities, hydraulics – be aware of scale-down.


Mamaroneck WWTP, Westchester County, NY

ScreeningGrit Removal

Primary Sedimentation

ScreeningGrit Removal

Primary Sedimentation

Activated SludgeActivated Sludge

Stacked Final Settling TanksSodium Hypochlorite Disinfection

Stacked Final Settling TanksSodium Hypochlorite Disinfection

How do you expand this constrained site and meet ~ 4 mg/L TN?


6+ Month Pilots of IFAS and MBBR

M

M

Aeration System

Feed PumpNo. 1

FM

Dissolved Air FlotationSodium Bicarbonate

Feed PumpNo. 2

FM

Post Aeration

Clarifier Unit

FM

Waste Sludge

MBBR PROCESS (TRAIN NO. 1)

IFAS PROCESS (TRAIN NO. 2)

Feed TankWith Screen

To Drain

Methanol

M

M

Aeration System

FM

FM

Primary Effluent FeedFrom WWTP Intermediate

Wet Well

Sodium Bicarbonate

R1 R2 R3

R4 R5 R6

MM

M

Aeration System

Feed PumpNo. 1

FM

Dissolved Air FlotationSodium Bicarbonate

Feed PumpNo. 2

FM

Post Aeration

Clarifier Unit

FM

Waste Sludge

MBBR PROCESS (TRAIN NO. 1)

IFAS PROCESS (TRAIN NO. 2)


To Drain

Methanol

M

M

Aeration System

FM

FM


Wet Well

Sodium Bicarbonate

R1 R2 R3

R4 R5 R6


MBBR with Post-Denitrification during the Last Month

Feed PumpNo. 1

SodiumBicarbonate Methanol

M

Feed Tank

To Drain


Wet Well

Aeration System

Clarifier UnitPost

Aeration

M


R1 R2 R3 R6

M


Major Findings

� Both IFAS and MBBR pilots achieved < 4 mg/L TN.

� Temperature = 11ºC

� Hydraulic retention time = 3 hours

� First pilot study to test media in the anoxic zone of an IFAS system.

� Presence of media effectively doubled the denitrification rate using methanol.

� Phased implementation design complete.

� Phase 1: IFAS using existing clarifiers.

� Phase 2: MBBR using some of the existing clarifier volume as MBBR; dissolved air floatation


Summary of Process Design Considerations

� Surface area is the key.

� Specific loading rates:

� BOD

� NH3N

� NO3N

Rock Trickling Filter Media (15 ft2/ft3)

Plastic Trickling Filter Media (30 ft2/ft3)

IFAS & MBBR Media (152 ft2/ft3)Design criteria depends

on desired removal rate (permit limits)



Practical Design Considerations




� Screening requirements

� Aeration system design

� Media retention sieves

� Approach velocities

� Foam and scum removal

� Maintenance provisions


Screening Requirements

� Purpose

� Remove materials that could entangle media or plug media retention sieves

� Design guideline

� 6 mm with primary treatment

� 3 mm without primary treatment

� Media size and shape should be considered


Aeration system design

� Multiple Functions

� Process air

� Mixing

� Sieve cleaning

� Fine or coarse bubble can be used

� Low maintenance requirements

� High structural integrity

� Oxygen transfer efficiency (OTE) is affected by:

� Diffuser type and arrangement (diffuser density, lateral spacing, airflow/diffuser, etc.)

� Media fill fraction

� Design for higher DO residual


Aeration System Optimization

Consider summer versus

winter operation

Winter

� Biofilm nitrification rates are low

� Consider higher DOs (4 to 5 mg/L)

� to reduce media requirements

Summer

� Biofilm nitrification rates are high

� Consider lower DOs (2 to 3 mg/L)

� to reduce airflow and energy requirements

DO Sensitivity

y = 60.

R2 =

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0

11.0

12.0

0 1 2 3 4 5 6 7 8 9 10

DO, mg/L

Eff

lue

nt

Am

mo

nia

, m

g/L


Media Retention Sieves� Types

� Cylindrical

� Wall

� Cylindrical sieves preferred for oxic zone

� Self cleaning

� Cylindrical sieve design criteria

� 2 inch headloss at peak flow

� HLR = 24 gpm/sf

� 1.5 fps – recommended max velocity through wall orifice to control headloss

� Typical diameters (12 & 16 inch)

� Typical lengths (5, 10, & 12 feet )


Media retention sieves (Cont.)

� Media retention sieves also required for

� Dewatering ports

� Basin overflows

� Control media creep

Basin overflow sieve at BroomfieldMedia creep at SAC


Anoxic media zones� Use wall sieves, not cylindrical

� cylindrical sieves can disrupt mixing pattern

� Air knife is required

� Operates only a few minute per day

� Mixers

� Slow speed submersible (Landia, EMU, ABS)

� Impeller designed to protect media

� Mixing energy 0.75 to 0.95 bhp/kcf

� Locate to create spiral roll

� Other possible mixer types

� Vertical bridge mounted

� Hyperclassic Invent

� Enersave mixer


Sieve Approach Velocity

� Approach velocity

� Flow (Q+RAS+MLR)/Basin Cross-Sectional Area

� Leads to Media “stack-up” around sieves

� Potential problems

� Increased sieve headloss

� Erratic OURs due to poor media distribution

� Suggested maximum design criteria

� 30 to 35 m/hr typical maximum

“Stack-Up”


Strategies to Reduce Approach Velocity and Avoid Media Stack-Up

� Reduce basin length to width ratio

� < 4:1 if possible

� Increase mixing energy under sieves

� Reduce MLR during peak flows

� Use longer sieves, in multiple rows

� Include media return airlift pump

� Spiral roll aeration design

� More cells in series


Example of How to Minimize Approach Velocity to Avoid Media Stack-up in a Plug Flow Reactor (Oxford, UK)

AX

AX

Ox1 – BOD Rem.

Ox1 – BOD Rem.

Ox1

Ox1

Gate to pass scum

Ox3 - polishing

Ox3 - polishing

Media Zone Inlet Channel

Ox2 - Media

Ox2 - Media


Foam and Scum Control

� Design/operate to reduce foaming potential

� Avoid excessively long SRTs and over aeration

� Eliminate low DO areas

� Balance sidestreamloads

� Avoid low alkalinity and pH

� Provide 2 to 3 ft of basin freeboard

� Chlorinated surface sprays

Chlorinated sprays are

controlling foam in

Broomfield and Cheyenne

Foam suppression spray

system


Maintenance Provisions

� Design hydraulics for one train out-of-service

� Media shuffle plan for taking basin off-line

� Media storage

� Media transfer pumps

� Biofilm integrity during storage?

� Odors during storage?



Applications of IFAS/MBBR in North

America

Applications of IFAS/MBBR in North

America

Slide - 49 IFAS and MBBR Webcast March 18, 2010October 10-14, 2009

Background

� Original plant

� Primary clarifiers

� Trickling filter activated sludge (TF/AS) process

� IFAS upgrade

� Expansion from 4 mgd to 8 mgd

� TIN of 6 mg/L

� 4-stage nit/denit configuration

Yucaipa, California


Primary Clarifiers and Converted Trickling Filters

Primary Clarifiers

Converted Rock TF to

Anoxic Volume


IFAS Basins and Secondary Clarifiers

IFAS Basins

New Secondary Clarifiers

Post Anoxic


Background

� First MBBR facility in North America using buoyant plastic media

� MBBR for tertiary nitrification following HPOAS

� 4.7 mgd ave. design flow

Moorhead, Minnesota


PrimaryClarifiers

Final Clarifiers

HPOAS

NitrificationMBBR

ChlorinationDechlorination

AnaerobicDigesters


Construction of Moorhead MBBR

Low cost construction

Media retention

sieves


Headworks (Hydroxyl)


-31ºF

-35ºC


Background

� Green field water reclamation facility

� 12 mgd design average flow

� Irrigation and deep well injection

� Nit/Denite MBBR

� TN < 10 mg/L

� BOD < 10 mg/L

� TSS < 5 mg/L

Fort Myers, Florida


MBBR/DAF Process Configuration(Fort Myers East WRF)

Disk

Filter

Sludge

Dewatering

Dissolved Air Flotation

MBBR Process

OX OXAX AXInfluent

OX

IR Pumping


Secondary Effluent

Diurnal Flow EQ/storage MF ROPre-Treatment

Disinfection (NH4 + NaOCl)

RO Brine

Ferric

Gravity Thickener

Polymer

Sodium Bisulfite and Antiscalant

Lime, Carbon Dioxide, NaOCl

UV/H2O2

Treated Water Storage

Bundamba Advanced WTP – Flow Schematic

Power Plants

Wivenhoe Dam



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