Transcript ADC Findings Related to Regulatory Criteria, Process and

Affordable Desalination Collaboration
Findings Related to Regulatory Criteria,
Process and Costs for Seawater
Desalination
Tom Seacord, P.E.
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ADC – Chairman of the Board of Directors
Goals of the ADC
1. Demonstrate affordable desalination using
innovative technologies & processes
2. Create a body of data that can guide & benefit
future designs
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3. Educate the public to show that desalination is
an affordable, viable source of fresh water
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Current and past members of the ADC have included
agencies, consultants, and leading manufacturers
West Basin
municipal water district
AMIAD
Zenon
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ADC’s work has included three different phases
1.
ADC 1: Demonstrating actual SWRO energy using
conventional pretreatment and full-scale commercial
technology (May 2005 - April 2006)
– Funded by ADC members
2.
ADC 2: Further demonstration using alternate pretreatment
and RO membranes (Jan - Nov 2009)
– Funded by Prop 50 and ADC members
3.
ADC 3: Brackish RO concepts
– Collier County, FL (June – Dec 2006)
– Funded by TWDB and ADC members (Feb - Dec 2010)
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ADC has proven that SWRO’s efficiency has improved
significantly using off-the-shelf technology
49.1
16000
11.4
43.0
14000
9.7
36.8
12000
8.1
30.7
6.5
24.6
4.9
18.4
3.2
12.3
1.6
6.1
2000
0
0
0
Specific Power (kW-hr/AF)
13.0
10000
8000
6000
4000
1970
1980
1990
2000
ADC 2006
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ADC’s work has been widely referenced when
defending desalination as a water supply alternative in
California
4.9
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3.2
26.4
18.4
12.3
1.6
6.1
0
0
8000
Specific Power (kW-hr/AF)
6.5
General
Perception
6000
Expert's
Perception
4000
ADC 2006
ADC 2006
SWRO Process
2000
0
State Project Water
Colorado Aqueduct Water
SWRO
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Background
California Water Supply & Treatment Costs
$3.6
$0.8
$3.0
$0.6
$2.4
$0.4
$1.8
$0.3
$1.2
$0.1
$0.6
$0
$0
$1,200
Supply & Treatment Cost ($/AF)
$0.9
$1,000
$800
$600
$400
Brine
Disposal
From
Inland
Empire
Area
Public
Perception
Expert
Perception
ADC 2006
Prod. &
Dist. Cost
$200
$0
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ADC 1 & ADC 2
US Navy Test Facility - Port Heuneme, CA
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ADC’s SWRO Demonstration Plant
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ADC SWRO Plant Schematic
40 Foot Containerized 200-350 m3/day SWRO Pilot
1.8 kWh/m3
6.8 kWh/kgal
3 x 7 element 8” RO vessels
E
Multi-Media
Filter
Holding
Tank
C
Supply
Pump
Micron Filter
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Seawater
Product
G
PX
A
Intake pier
Seawater
Return
PX Boost
Pump D
HP
Pump
F
Reject
B
H
Typical ADC Operating Conditions
Stream
A
B
C
D
E
F
G
H
GPM
93
51
43
51
93
42
51
51
PSI
35
20
20
737
763
5
747
10
TDS
34k
34k
34k
35k
35k
103
66k
65k
10
ROSA6.0 Projections SW30XLE-400, 7.2 gfd, 45% recovery, 60°F, 34,432 TDS feed, 0.85 Fouling
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Testing Protocol
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Test Parameters & Data Collection
• Variables
–
–
–
–
Flux rates: 6, 7.5, 9 gfd
Recovery: 35, 42.5, 50%
Membrane Rejection: 99.5%-99.8%
Plant size: 10, 50 MGD
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• Data analysis
–
–
–
–
–
–
Power consumption
Feed pressure and membrane DP
ASTM normalized data
Feed quality
Permeate quality and Boron
NPV of capital costs vs. O&M (energy costs)
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Cost Estimating Procedures
• Net Present Value Analysis
– Amortized capital costs
• Project Life 30 years, 5% interest
• Co-location
– 10 MGD: Co-located with WWTP outfall, new open intake
– 50 MGD: Co-located intake/outfall with power plant
– Annual O&M
• Power $0.08/kW-hr
• Replacement of Membranes (CARR)
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– To maintain performance (energy & permeate quality)
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50-MGD Conceptual Study
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50-MGD Conceptual Study
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Pressure Center
• Pump Center
• Energy Recovery Center
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10-MGD Conceptual Study
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10-MGD Conceptual Study
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Dedicated Pumps/ERDs
• Feed pump for every train
• Energy recovery for every train
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Test Results
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Pretreatment
Raw Turb
RO Feed Turb
10
• Initial Filtration Problems
SDI
– Red tide
6
– Not exceeded 86%
• Turbidity < 0.1
– Not exceeded 88%
Turbidity (NTU)
• SDI < 5
1
4
3
0.1
2
Silt Density Index
5
1
0.01
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0
200
400
600
0
800 1000 1200 1400 1600
Run Time (hours)
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Impact of Feed Pump - Scalability
PD Pump Selected for ADC
– High efficiency
– Pulsating flow
Centrifugal Pumps Used for
Larger Trains
– Low efficiency for small
pumps
– Smooth flow
•
Pressure Center Design
– May reduce power @ low
flow rates
• 50 MGD Case Study
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– 5.9 to 8.9 kWh/kgal
• 10 MGD Case Study
– 6.6 to 9.8 kWh/kgal
Specific Power (kW-hr/m3)
•
12
2.5
2.3
2.0
2.3
2.0
1.8
Specific Power (kW-hr/kgal)
•
10
8
6
4
SW30HR-380, 6 GFD @ 50%
SW30XLE-400i, 9 GFD @ 50%
2
SW30HR LE-400i, 6 GFD @ 50%
0
0
0
2
4
6
8
10
Train Size (MGD)
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• Flux  = Boron 
• Recovery  = Boron 
• Low energy membrane
produced marginally
acceptable boron
– SW30HR-380
• 0.45 to 0.85 mg/L
– SW30XLE-400i
• 1.05 to 1.44 mg/L
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– SW30HR LE-400i
• 0.45 to 0.85 mg/L
SW30XLE-400i Permeate Boron (mg/L)
Permeate Quality - Boron
2.0
6 GFD
Boron < 1.45 mg/L
to comply with
California standard
7.5 GFD
1.8
9 GFD
1.5
1.3
1.0
0.8
0.5
0.3
0.0
35%
43%
Recovery
50%
Permeate Quality - Boron
SW30HR-380 Permeate Boron (mg/L)
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2.0
1.8
6 GFD
7.5 GFD
9 GFD
Boron < 1.45 mg/L to comply
with California standard
1.5
1.3
1.0
0.8
0.5
0.3
0.0
35%
43%
Recovery
50%
Permeate Quality - TDS
• Flux  = TDS 
• Recovery  = TDS 
• Low energy membrane
produced highest TDS
400
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SW30XLE-400i Permeate TDS (mg/L)
6 GFD
350
7.5 GFD
9 GFD
300
– SW30HR-380
250
• 80 to 175 mg/L
200
– SW30XLE-400i
• 190 to 350 mg/L
150
– SW30HR LE-400i
100
• 95 to 295 mg/L
50
0
35%
43%
Recovery
50%
400
6 GFD
350
7.5 GFD
9 GFD
300
250
200
150
100
50
0
35%
43%
Recovery
50%
SW30HR-380 Permeate TDS (mg/L)
SW30HR LE-400i Permeate TDS (mg/L)
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Permeate Quality - TDS
400
6 GFD
350
7.5 GFD
300
9 GFD
250
200
150
100
50
0
35%
43%
Recovery
50%
Treatment Costs
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$8,0
$2,280
$7,0
$1,955
$1,629
$1,303
$978
$652
$325
$-
6 GFD O&M
7.5 GFD O&M
9 GFD O&M
6 GFD Total Water
7.5 GFD Total Water
9 GFD Total Water
6 GFD Capital
7.5 GFD Capital
9 GFD Capital
$8
$7
$6,0
$6
Capital
Cost
$5,0
$4,0
$4
$3,0
Total
Cost
$2,0
O&M
Cost
$1,0
$0,0
30%
$5
$3
Capital Cost ($/gpd)
$2,607
O&M & Total Costs ($/kgal)
O&M & Total Costs ($/Acre Foot)
Estimated Costs for 50-MGD SWRO WTP (SW30HR-380)
$2
$1
35%
40%
45%
50%
$0
55%
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Treatment Costs
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$8,0
$18
$2,280
$7,0
$16
$1,955
$1,629
$1,303
$978
$652
$325
$-
Capital
Cost
$6,0
Total
Cost
$5,0
$14
$12
$10
$4,0
$8
$3,0
O&M
Cost
$2,0
$1,0
$0,0
30%
$6
Capital Cost ($/gpd)
$2,607
O&M & Total Costs ($/kgal)
O&M & Total Costs ($/Acre Foot)
Estimated Costs for 10-MGD SWRO WTP (SW30HR-380)
$4
6 GFD O&M
7.5 GFD O&M
9 GFD O&M
6 GFD Total Water
7.5 GFD Total Water
9 GFD Total Water
6 GFD Capital
7.5 GFD Capital
9 GFD Capital
35%
40%
45%
50%
$2
$0
55%
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Summary
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Conclusions
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• Flux & recovery impact permeate quality
• Low energy SWRO membrane has lowest cost, but
poorest permeate quality
• Due to size and type of pump, 10 MGD plant less
efficient
– 10 MGD – 6.6 to 9.8 kWh/kgal
– 50 MGD – 5.9 to 8.9 kWh/kgal
• ADC’s design  power by
– 10 MGD – approx. 30% over industry perception
– 50 MGD – approx. 40% over industry perception
– Low = 5.98 kW-hr/kgal
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Conclusions (cont.)
• Recovery of 50% resulted in lowest NPV
• Improving boron/TDS rejection results in higher energy
use & treatment cost
• SWRO is competitive with other supply options in
California
– 10 MGD
• $1,552 to $1,820/AF
– 50 MGD
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• $794 to $966/AF
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Recommendations
• Data must be taken in context of raw water
quality (i.e., temperature)
• Designers must consider public values when
establishing design water quality (i.e., boron)
• Future Work
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–
–
–
–
Pretreatment
Higher Recovery
Long Term Testing
Economy of Scale – Large Diameter Elements
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ADC’s Publications & Outreach
1.
Seacord, et al. 2006. Affordable Desalination Collaboration 2005
Results. Desalination & Water Reuse Quarterly. Vol. 16:2.
2.
Seacord, et al. 2007. ADC 10 MGD Case Study. Proc. 2007 AMTA
Annual Conf.
3.
MacHarg, et al. 2008. ADC Baselines SWRO Performance.
Desalination & Water Reuse Quarterly. Vol. 18:2.
4.
Dundorf, et al. 2009. Optimizing Lower Energy Seawater
Desalination. Proc. 2009 IDA World Congress.
5.
AMTA Preconference Workshops
– 2008, 2009, 2011
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