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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?
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