David W. Arnott, P.E.

Government Affairs Seminar

February 23, 2012

TOPICS COVERED

Disc Filtration

Ballasted Setting

Continuous BackWash Filter

Membrane Bioreactors (MBR’s)

Technologies

Levels of Treatment

Costs

Sizing

PRESENTATION WILL NOT COVER

Regulations

Nutrient Trading

Adaptive

Management

DISC FILTER APPLICATIONS

Effluent Filtration

Water Re-use

Phosphorus Reduction

CSO/SSO

DISC FILTER OPERATION

Gravity Flow

Partially Submerged

Stationary Filter Discs

Automatic Operation

Continuous Operation

DISC FILTER INSTALLATION

(Concrete)

Outlet

weir

Access platform

elevation Inlet

trough

Bypass

weir

Influent

channel

FLOW Filter effluent

channel

Emergency

bypass

channel

0

2

4

6

8

10

12

0 5 10 15 20 25

Eff

lue

nt

Tu

rbid

ity, N

TU

Influent Turbidity, NTU

Upflow

Dual-medium

Deep-Bed

Mono-medium traveling bridge

Dual-medium traveling bridge

AAS CMDF

Disc Filter

DISC FILTER PERFORMANCE

(Turbidity)

OCONOMOWOC, WI

OCONOMOWOC, WI

TERTIARY POLISHING

OCONOMOWOC, WI

TERTIARY POLISHING

OCONOMOWOC, WI

TERTIARY POLISHING

PHOSPHORUS LEVELS & TECHNOLOGY

1.0 mg/l

0.50 – 0.30 mg/l

0.30 – 0.20 mg/l

< 0.20 mg/l

Coagulant

Multipoint coagulant addition

Assisted with biological

Coagulant

Biological

Coagulant and Polymer ?

Disc Filter

Coagulant

Biological

Coagulant and Polymer

Disc Filter

Secondary

Clarifier Effluent

COAGULATION/FLOCCULATION

PRIOR TO FILTRATION

Disc filter Coagulation (3 - 5 min HRT)

Polymer

Static Mixer

Flocculation (3 - 6 min HRT)

Filtered Effluent

Solids

VFD VFD Coagulant

PILOT STUDY - CLINTON, MA

(MARCH/APRIL 2011)

Disc Filtration used for total Phosphorus

removal - <0.10 mg/L

Normal and Stressed Conditions

Ferric Chloride and Aluminum Sulfate Used

CLINTON, MA

0.47

0.76

0.47

0.53

0.48

0.52

0.46 0.45 0.43

0.058 0.072 0.078

0.099

0.041 0.029

0.073 0.078 0.074

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

Apr18/8hr Apr18/24hr Apr19/8hr Apr19/24hr Apr20/8hr Apr20/24hr Apr21/8hr Apr21/24hr Apr22/4hr

Tota

l Ph

osp

ho

rus

(mg/

l)

Sample Date / Composite Duration

Clinton, MA Kruger Disc filter Pilot Study Week Four - April 18 to April 22

Influent TP

Effluent TP

BALLASTED SETTLING –

PROCESS CHEMISTRY

MICROSAND

Stable particles

suspended in

water

Polymer

Molecule

Concentrated Solids

Concentrated Solids

Clear Water

Unstable

Coagulated Particles

Flocculated Particles

Metal Salt

Polymer molecules bridge between suspended particles,

“glue” them together as “flocs”, and concentrate the solids

Stable particles

suspended in

water

Polymer

Molecule

Concentrated Solids

Concentrated Solids

Clear Water

Unstable

Coagulated Particles

Flocculated Particles

Metal Salt

Polymer molecules bridge between suspended particles,

“glue” them together as “flocs”, and concentrate the solids

BALLASTED SETTLING –

FLOC PARTICLE

~ 150 µm

Secondary

Clarifier Effluent

BALLASTED SETTLING – COAGULATION/FLOCCULATION

Disc filter Coagulation (3 - 5 min HRT)

Polymer

Static Mixer

Flocculation (3 - 6 min HRT)

Solids

VFD VFD Coagulant

BALLASTED SETTLING –

PROCESS SCHEMATIC

High Rate Clarifier, 30-50 gpm/ft2

BALLASTED SETTLING -

HYDRO CYCLONE SLUDGE SEPARATION

SLURRY

FEED

OVERFLOW

(SLUDGE)

AIR CORE

INNER

VORTEX

OUTER

VORTEX

APEXUNDERFLOW

(SAND)

APEX

SLURRY

FEED

OVERFLOW

(SLUDGE)

AIR CORE

INNER

VORTEX

OUTER

VORTEX

APEXUNDERFLOW

(SAND)

APEX

Caldwell WWTP, ID

ACTIFLO Pilot Study Results without Biological Phosphorus Removal Upstream

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0.45

0.50

1 2 3 4 5 6

24 Hour Composite Sample Number

Eff

lue

nt

To

tal

Ph

os

ph

oru

s

(mg

/l)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

Infl

ue

nt

To

tal

Ph

os

ph

oru

s

(mg

/l)

Pilot Unit Efluent Total P Pilot Unit Influent Total P

Average Ferric Chloride Dose = 126 mg/l

Average Influent TP = 3.0 mg/l

Average Effluent TP = 0.04 mg/l

BALLASTED SETTLING –

CALDWELL, ID PILOT STUDY RESULTS

EXTENDED RUN WITH FERRIC CHLORIDE Bio-P Selector Bypassed

Influent Total Phosphorus Increased from 0.3 mg/l to 3mg/l

Achieve 70 ppb Effluent Total Phosphorus

CONTINUOUS BACKWASH FILTER

Regenerative Adsorptive Column

Coagulant Ferric Sulfate or Ferric Chloride

CONTINUOUS BACKWASH FILTER Biological

System

RAS

Secondary Clarifier

Digester

Solids

WAS

Optional 2nd Pass

Reject Recycle

Headworks

Dewatering

Back Wash Filter

Rapid Conditioning

Zone

Secondary Effluent

Clean Wate

r

Reject Stream

Wat

er

Particles

HFO Sand Grain

Fe

Fe

Fe

O

O

As

O

OPO43-

CONTINUOUS BACKWASH FILTER

CONTINUOUS BACKWASH FILTER

Hydrous Ferric Oxide-

Coated Sand Images from scanning

electron microscopy

X-ray Flourescence

Fe

P

CONTINUOUS BACKWASH FILTER

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0.45

0.50

12/1

4

12/1

9

12/2

4

12/2

9

1/3

1/8

1/1

3

1/1

8

1/2

3

1/2

8

2/2

2/7

Tota

l P

hosp

horu

s (

mg

/L)

Date (month/day)

1st Pass

2nd Pass

Water/Air

Flow

Treated water

Sludge

Membrane

Aeration

Membrane Bioreactor

MBR

MBR PROCESS

Screening & Grit Removal, < 2mm

Biological Reactors N-DN Bio-P

Membrane Tanks Mixed Liquor Pumps (WAS) Permeate Pumps

MBR - MEMBRANES

3.0 micrometer

3.0 micrometer Pore diameter (micron)

東レ BF014

クボタ

0

0.5

1

1.5

0 0.2 0.4 0.6 0.8

Nu

mb

er o

f p

ore

(1

0 1

2 /

m 2

)

PVDF Membrane

Type B

Pore diameter (micron)

東レ BF014

クボタ

0

0.5

1

1.5

0 0.2 0.4 0.6 0.8

Membrane

Choice “A”

0.0

0.2

0.4

0.6

0.8

0 1000 2000 3000 4000

ろ過速度

［m/d］

0

1

2

3

0 1000 2000 3000 4000

運転時間［h］

運転圧力

［kPa］

Toray

Toray

A Company

A Company

Operation Time (h)

Tra

ns

Mem

bra

ne

Pre

ssu

re (

kP

a)

Flu

x (

m/d

)

Fixed Flux Fixed TMP0.0

0.2

0.4

0.6

0.8

0 1000 2000 3000 4000

ろ過速度

［m/d］

0

1

2

3

0 1000 2000 3000 4000

運転時間［h］

運転圧力

［kPa］

Toray

Toray

A Company

A Company

Operation Time (h)

Tra

ns

Mem

bra

ne

Pre

ssu

re (

kP

a)

Flu

x (

m/d

)

Fixed Flux Fixed TMP

MBR FLUX & PRESSURE Comparison of Immersed Membrane Modules

MLSS: 10,000 mg/l

Type B Flat Sheet

FLAT SHEET MEMBRANE

0.08 mm nominal pore

size

~15 ft2 (~1.4m2) per

element

5.3’ High x 1.7’ Wide x

0.04’ Thick

PHASED MBR - N-DN PROCESS

DENITRIFICATION

4-5Q Sludge Recycle

MBR

MBR

MBR

MBR

NITRIFICATION

PHASED MBR – WITH BIO P REMOVAL

DENITRIFICATION

4-5Q Sludge Recycle

MBR

MBR

MBR

MBR

NITRIFICATION

Selector

MBR OPERATING MODES:

FILTRATION AND RELAXATION MODE

Relaxation (Intermittent Filtration) 10 minute cycle: 9 minutes filtration followed by 1 minute

relaxation and suspension of permeate (aeration is continuous)

Scour

Aeration

9 mins 1 min 1 min 1 min 9 mins 9 mins

Filtration

MBR - MEMBRANE TANKS

MBR - BERMUDA

Operating since Oct 2009

0.25 MGD

Gravity Flow Permeate

Membrane Thickening

MBR - MEMBRANE TANKS Two tanks – Five modules each

Membrane thickening: One tank, one module

LEVELS OF TREATMENT

Disc Filtration > 0.15 mg/L TP

Ballasted Settling > 0.06 mg/L TP

Continuous Back Wash Filter < 0.06 mg/L TP

MBR < 0.06 mg/L TP

Approximate

WHICH TECHNOLOGY?

EQUIPMENT COSTS FOR PHOSPHORUS

REMOVAL

$0

$1,000,000

$2,000,000

$3,000,000

$4,000,000

$5,000,000

$6,000,000

$7,000,000

$8,000,000

0 10 20 30 40 50 60

Capit

al C

ost

Capacity, MGD

Disc Filters >=0.15 mg/L TP

Ballasted Settling >=0.06 mg/L TP

Membranes < 0.06 mg/L TP

Continuous Backwash Filter <0.06 mg/L TP

WWTF FACILITY UPGRADE COSTS

FOR PHOSPHORUS REMOVAL

$0

$5,000,000

$10,000,000

$15,000,000

$20,000,000

$25,000,000

0 10 20 30 40 50 60

Capit

al C

ost

Capacity, MGD

Disc Filters >=0.15 mg/L TP

Ballasted Settling >=0.06 mg/L TP

Membranes < 0.06 mg/L TP

Continuous Backwash Filter <0.06 mg/L TP

O & M COSTS

$0.20

$0.25

$0.30

$0.35

$0.40

0 10 20 30 40 50 60

O&

M C

ost

per

1,0

00 g

al

Capacity, MGD

Continuous Backwash Filter

MBR

EQUIPMENT SIZING

Not always peak hour flow

365 Day Average, Total P Limit

Blending Potential

DISC FILTRATION – TAKE AWAYS

Tertiary Polishing Phosphorus Treatment

Phosphorus Reduction – Need Coagulation or

Flocculation

In-pipe dosing not sufficient

Mixing, energy critical

Floc needs structural integrity

Use existing tankage (if possible)

BALLASTED SETTLING - TAKEAWAYS

Enhanced Floc Formation

Shorter HRT Higher Loading Rate

Mixing energy critical

Use existing tankage

(if possible)

CONTINUOUS BACKWASH FILTERS -

TAKEAWAYS

Regenerative Adsorption Process

Hydrous Ferric Oxide-Coated

Sand

Multiple Passes for Additional

Treatment

Lower Coagulant Dose

Reject Stream

Possible Re-use

Fe

P

MBR - TAKEAWAYS High level of treatment P

Water reuse

Micropollutants

Energy intensive

High Capital Cost

Compact footprint

Membrane fouling critical Aeration

Intermittent relaxation

Backwashing

Citric Acid

QUESTIONS?