Reclaimed wastewater facility using Ozone
and Ceramic Membranes
Shinjiro Kanaya, METAWATER USA
Motoharu Noguchi, METAWATER,Co.Ltd
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Background
1. Water Reuse Project in Japan “Sewer Vision 2100”
Water shortage in urban area, Tokyo, Yokohama, Kobe, etc.
Encourage developing water reclamation technology
2. Increased reclaimed water demand
Growing demand for water reuse of secondary effluent
Non-portable reuse, Landscaping irrigation etc.
METAWATER and Tokyo Metropolitan government have conducted
collaborative research since 2006
 Full scale installation in 2010

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Tokyo metropolitan government
•
•
•
•
•
Population: 12 Million / Service area : 1,800km2(700sq miles)
Bureau of Water work
1,400MGD : Treated wastewater
130 MGD : reuse water for landscaping and sprinkling
100 MGD: use for non-portable reuse, sanitary flushing, etc
• 1MGD ozone + polymeric membrane operated since 2005
• 2MGD ozone+ ceramic membrane operated in 2010
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Water reclamation development target
Produce “high quality” & “low cost” reclaimed water
High
Sprinkling,
Snow melting, etc.
Landscape,
Sanitary flushing, etc.
RO
Conventional
technologies
Cost
Activated
Carbon
MF/UF
Ozone +
Sandfilter
Sandfilter
Low
Industrial use,
water recharge, etc.
Ozone +
Ceramic Membrane.
New value
Secondary
effluent
Low
Water quality
High
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Benefit of Ceramic Membrane System
• High quality water
– Mechanical strength
• High integrity -No breakage
– Uniform pore size distribution
• Reliable physical separation
• Water saving
– High feed water recovery >98%
• Energy Saving
– Electric power consumption< 0.1 kWh/m3 (0.38 Wh/gal)
• Low Maintenance
– Long membrane Life >20years
– Easy chemical cleaning
• Design flexibility
– Combination with enhanced treatment (e.g.) coagulation,
pre-ozonation, Powdered Activated Carbon (PAC)
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Ceramic Membrane Element
Nominal pore size
Dimension
Membrane surface area
Size of channel
Number of channel
Material
Flow rate
0.1micron
180mm x 1,500mmL
( 7.1” x 59.1”)
25m2 (269ft2)
2.5mm (0.1”)
2000
Ceramic
18gpm at 100gfd
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Structure of Ceramic membrane element
Raw
water
channel
Cross section
Filtrate channel
Raw water
Filtrate
Water
collection slit
Support layer
Membrane layer
(0.1micron pore size)
Membrane Surface
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Filtration and backwash process
Backwash process
Filtration
process
Reverse flow
Raw water
Dead-end
filtration
Operation
Mode
Pressure
TMP< 20psi
Duration
1 - 2hr
Wastewater
Compressed air
Backwash water
Backwash water
Filtrate
Schematic
diagram
Discharge
Wastewater
Reverse flow
by filtrate
70psi
2 - 20 seconds
Air flushing
by air/water
30psi
2-5 seconds
Total 1minutes
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Concept of combination of Ozonation/
Coagulation / Ceramic membrane
Coagulation
Improvement
Ozonation
Coagulation
Microorganisms &
Virus Inactivation
TOC & DOC Removal
Color and Odor Removal
Reduce TMP increasing rate
Ozone
Resistance
Coagulate / pin floc
Fouling control
Ceramic
Membrane
Turbidity / Particle Removal
Stable Operation
Robustness
>120 installation, No breakage to date
since first installation in1998
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Schematic flow of Water reclamation system
*Biofilter
Ozonation
･NO2 removal
・ Color removal
Coagulation
improvement
･SS removal
Secondary
Effluent
Biofilter
Ceramic membrane
・Dead-end filtration
・Backwash interval:1-3hrs
Filtrate
Coagulant
Ozone
contactor
DO3
Blower
Coagulation
Coagulation tank
pump
Ozonizer
* Biofilter process is optional
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Operation Result
• Test site:
• Raw water:
• Flow:
Shibaura WWTP, Tokyo
Secondary effluent
Biofilter-O3-coagulation- MF ceramic
membrane
• Pilot testing
– Period: 2006-2008
– Single membrane module unit
• Full scale operation
– 1.8 MGD (108 membranes)
– Start up April 2010
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Pilot test - Equipment
Ozone Contactor
Ceramic Membrane unit
Single membrane unit
Capacity: 18.3gpm at 100gfd
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Pilot test - Results (ozonation / coagulation effect)
40 3.6kPa/day
(0.5psi/day)
30
5.8
20
2.9
4.3
0.9kPa/day
(0.1psi/day)
10
1.4
0
O3=6mgO3/L, PACl=0mgAl/L
8.7
60
13kPa/day
(1.9psi/day)
40
20
2.9
1.2kPa/day
(0.2psi/day)
0
0
5
10
Time course (day)
15
Preozonation effect
on TMP increase rate
TMP increase rate reduced
1/4 by ozonation
5.8
0
5
10
Time course (day)
TMP (psi at 25C)
O3=0mgO3/L, PACl=4.8mgAl/L
TMP (kPa at 25C)
50
O3=6mgO3/L, PACl=2.4mgAl/L
80
TMP (psi at 25C)
TMP (kPa at 25C)
O3=6mgO3/L, PACl=4.8mgAl/L
15
PACl coagulation effect
on TMP increase rate
TMP increase rate reduced
1/10 by coagulant(PACl)
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DOC [mgC/L]
Pilot test - TOC fraction distribution
Secondary effluent
Biofilter effluent
Ozone treated water
Ceramic MF effluent
7
6
5
4
3
2
1
0
DOM
AHS
HoN
HiA
DOM: Dissolved Organic Matter
•AHS:
Hydrophobic Acid
•HoN:
Hydrophobic Neutrals
•HiA:
Hydrophilic Acid
•Bas:
Bases
•HiN:
Hydrophilic Neutrals
BaS
HiN
（Komatsu, et al)
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Pilot test - Coagulation enhancement by
ozonation
1. Ozone imparts negative charge to particles
2. Negative charged particles attract to positive charged coagulant
3. Neutral floc formed course high permeability cake layer
ｰ ｰ+ｰｰ
ｰｰ ｰ
ｰ ｰ+ｰｰ
ｰｰ ｰ
Particle
ｰ ｰ+ｰｰ
ｰｰ ｰ
ｰ ｰ+ｰｰ
ｰｰ ｰ
ｰ ｰ+ｰｰ
ｰｰ ｰ
Ozone
ｰｰ
ｰ
ｰ
ｰ +ｰｰｰ +ｰｰ
ｰｰ ｰ OHAlｰOHOH
Al Al
OHAl
ｰ
Al OHAl ｰ ｰ
+ｰ
ｰ
ｰ
ｰ
ｰｰ
ｰ+ ｰ
ｰｰ ｰ OHAlOHOH
Al Al
OHAl
ｰｰ
Al
OHAl ｰ
ｰ
ｰ +ｰｰ
ｰｰ+ｰｰ
ｰｰ ｰ
Coagulant
Removed by MF
Ceramic membrane
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Full scale installation (Shibaura WWTP)
• Capacity : 1.85MGD (7,000 m3/day)
• Biofilter : φ4.5m x 4 tanks = 120 m/day
• Ozonizer : 133ppd
2.5 kg-O3/hr x 2
• Ceramic membrane : 54membrane x 2units
Ceramic membrane
building
Ozonizer building
Operated since
April 2010
Ozone contactor
Biofilter
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Full scale installation (Shibaura WWTP)
•Membrane unit (6racks, 9membranes per rack)
•Each rack can be isolated
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Full scale operation – TMP Long term
Residual
ResidualO3
O3：0.1
：0.1～
～0.5mgO3/L
0.5mgO3/L(0.3
(0.3mg/L
mg/Lmore
morethan
than90%
90%of
oftime)
time)
pH
pHcontrol
control：6.3
：6.3～
～6.8
6.8
PACl
PACldosage：20
dosage：20～
～68mgPACl/L
68mgPACl/L
BW
BWcycle:
cycle:2hours
2hours CEB:
CEB: soak
soak10ppm
10ppmHypo
Hypo11per
per3-7days
3-7days
TMP
Flux
20
CIP
200
CIP 1 rack per month
160
15
120
10
80
5
40
0
1-Apr-10
Flux (gfd)
Initial TMP（Psid at 25 ℃）
25
0
28-Sep-10 27-Mar-11 23-Sep-11 21-Mar-12 17-Sep-12 16-Mar-13
Stable membrane filtration demonstrated at the
high flux without CIP.
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Full scale operation - Distribution of ozone
injection rate
Dissolved ozone concentration of ozone contactor effluent
Ratio (%)
20
0.1mgO3/L
0.3mgO3/L
0.5mgO3/L
15
10
5
0
0
5
10
15
20
25
Ozone injection rate (mgO3/L)
•Dissolved ozone of 0.3mg/L
•Average ozone dosage : 7mgO3/L
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Full scale operation –
Membrane Cleaning by residual ozone
12
0.5
TMP
ozone concentrasion
0.4
9
0.3
6
0.2
3
0.1
0
24-Jan-11
25-Jan-11
0.0
26-Jan-11
Ozone conc. before membrane
(mgO3/L)
TMP　(Psid　at 25℃)
15
Ozone cleaning period
Ozone residual 0.1mg/L
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Full scale operation - Reclaimed water quality
SS
mg/L
COD
mg/L
DOC
mg/L
T－P
mg/L
Turbidity
NTU
Raw water
(2nd
effluent)
1.4
(0 – 5)
9.3
(4 – 13)
5.9
(3 – 8)
0.4
(0.1 – 3.4)
1.6
(0.3 – 7.7)
15
(4 – 23)
Color
Unit
MPN
Coliform /100mL 330 – 2800
1400
Norovirus Copy/L
870
Color
Biofilter
effluent
Ozone
effluent
Ceramic
membrane
filtrate
Target
Value
–
＜1
n/a
5.2
(3 – 7)
5.6
(2 – 7)
0.1
(0 – 1)
7.4
(3 – 11)
5.6
(2 – 7)
0.3
(0.1 – 1.6)
0.5
(0.1 – 2.8)
15
(4 – 23)
0.2
(0 – 0.7)
2.8
(0.9 – 4.4)
3.8
(1 – 5)
4.3
(2 – 6)
0.1
(0.0 – 0.5)
＜0.1
(0 – 0.6)
1.0
(0.1 – 2.8)
70 – 240
ND
ND
Not
detected
2200
630
ND
ND
n/a
–
n/a
n/a
n/a
＜1
3
average (min. – max.)
Norovirus : upper value=G1, lower value=G2
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Full scale operation - Turbidity & color
16
Raw water
Biofilter effluent
Membrane filtrate
Turbidity (NTU)
14
12
10
8
Target <1
6
4
2
Color (Color unit)
0
25May
Jul
Oct
Jan
Apr
Jul
Oct
Jan
Apr
20
15
Target <3
10
5
0
May
Jul
2010
Oct
Jan
Apr
2011
Jul
Oct
Jan
Apr
2012
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Full scale operation - Water quality
Color removal
Raw water (Secondary effluent)
Membrane filtrate
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Conclusions
1)
1) AAhybrid
hybridsystem
systemof
ofpre-ozonation
pre-ozonation/coagulation/ceramic
/coagulation/ceramicmembrane
membrane
filtration
filtrationwas
washighly
highlyeffective
effectivefor
forreclaimed
reclaimedwastewater
wastewatertreatment.
treatment.
2)
2) Hybrid
Hybridsystem
systemoperated
operatedwith
withvery
veryhigh
highfiltration
filtrationflux
fluxof
of
3
2
100gfd
100gfd(4.2m
(4.2m3/m
/m2/d)
/d)stable
stablemembrane
membranefiltration
filtration
demonstrated
demonstratedwithout
withoutCIP.
CIP.
3)
3) Dissolved
Dissolvedozone
ozonewas
waseffective
effectiveto
toremove
removeorganic
organicfoulants
foulantswith
with
“NO”
“NO”deleterious
deleteriouseffect
effecton
onceramic
ceramicmembrane.
membrane.
4)
4) Hybrid
Hybridsystem
systemwas
waseffective
effectivefor
forthe
theremoval
removalof
oforganic
organicmatters,
matters,
COD
by 50%, and color by about 80% as well as Bacteria and virus,
CODMn
Mn by 50%, and color by about 80% as well as Bacteria and virus,
and
andproduced
producedsafe
safewater
waterepidemiologically.
epidemiologically. Quality
Qualityof
ofthe
thefiltrate
filtrate
met
metthe
theCalifornia
Californiastandards.
standards.
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Acknowledgement
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