Concentrate and permeate treatment
processes for improving the sustainability
of inland brackish water desalination
W. Shane Walker, Ph.D.
Anthony Tarquin, Ph.D.
Center for Inland Desalination Systems
The University of Texas at El Paso
Multi-State Salinity Coalition Summit
Las Vegas, Nevada
January 26, 2012
Objectives
• Review indicators of sustainability
• Highlight several CIDS investigations
demonstrating improved sustainability
Sustainability
Environmental
SocioPolitical
Economic
Select Sustainability Indicators
•
•
•
•
•
Higher water recovery (product/feed)
Environmental
Lower specific energy
consumption (kWh/kgal)
Less chemical consumption, waste production
Lower economic cost ($/kgal; $/MGD)
SocioTechnical/operational
complexity
Economic
Political
Inland Membrane Desalination
pretreatment
membrane
process
Brackish Water Source
permeate
treatment
Distribution
concentrate
treatment
Reuse/Disposal
Permeate Treatment
pretreatment
membrane
process
Brackish Water Source
permeate
treatment
Distribution
concentrate
treatment
Disposal
Permeate Stabilization by Calcite
Carollo Engineers, Inc. and Shane Walker, UTEP
Texas Water Development Board (1004831105)
Three-step process
1. Lower pH with CO2
– Relatively abundant and inexpensive gas
2. CO2 reacts with calcite
– CO2 + CaCO3 → Ca2+ + 2 HCO3-
3. Add small dose of base for LSI > 0
Permeate Stabilization by Calcite
Carollo Engineers, Inc. and Shane Walker, UTEP CIDS
Texas Water Development Board (1004831105)
• Feed: KBH permeate
• TOMCO2: pH 5.6-5.7
• Upflow calcite contactor
– Media: 0.5-2 mm particles
– EBCT: 1-10 min
– Overflow: 2-17 gal/ft2/min
• Product Quality:
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–
–
–
pH: 7.5-8.5
Ca2+: 20-30 mg/L
ALK: 50-75 mg/L (as CaCO3)
LSI: -0.5-0.0
• Energy: < 0.1 kWh/kgal
Concentrate Treatment
pretreatment
membrane
process
Brackish Water Source
permeate
treatment
Distribution
concentrate
treatment
Disposal
CERRO
Anthony Tarquin, UTEP
US Bureau of Reclamation, DWPR R10AP81217
• Concentrate Enhanced Recovery RO (CERRO)
• Batch-continuous seawater RO process
exploiting induction time of precipitation
concentrate
Seawater RO
Distribution
CERRO
Anthony Tarquin, UTEP
US Bureau of Reclamation, DWPR R10AP81217
• Demonstrated at
KBH (El Paso) and
BGNDRF (Alamogordo)
• Feed: KBH- >10,000 mg/L
BGNDRF- 6000 mg/L
• Product Flow: 1 gpm
• Recovery: KBH- 97%
BGNDRF (ongoing)
• Energy: 6-7 kWh/kgal
(w/ energy recovery)
Zero Discharge Desalination (ZDD)
Tom Davis & Malynda Cappelle, UTEP
US Bureau of Reclamation, DWPR R10AP81212
• Demonstrated at
KBH (El Paso) and
BGNDRF (Alamogordo)
• BGNDRF Feed: 2500 mg/L
• NF/RO and Electrodialysis
Metathesis (EDM)
• Product Flow: 20 gpm
• Recovery: 97-98%
• Energy: 6.6 kWh/kgal
Conclusions
Sustainability of inland brackish water
desalination can be improved by:
– increasing system recovery
– reducing specific energy consumption
– reducing chemical consumption and production
– reducing economic cost
– designing appropriate technical complexity
Acknowledgements
• Permeate Stabilization by Calcite
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Texas Water Development Board
El Paso Water Utilities, KBH Desalination Plant
Carollo Engineers: Winnie Shih, Bradley Sessions, Justin Sutherland
UTEP CIDS: Luis Maldonado, Cora Martinez, Sami Al-Haddad
• CERRO (High Recovery)
– US Bureau of Reclamation, BGNDRF (Alamogordo, NM)
– UTEP CIDS: Anthony Tarquin, Guillermo Delgado
• ZDD (High Recovery)
– US Bureau of Reclamation, BGNDRF (Alamogordo, NM)
– UTEP CIDS: Tom Davis, Malynda Cappelle, Lucy Camacho,
Noe Ortega, Jesse Valles
Questions or Comments
W. Shane Walker, Ph.D.
Assistant Professor
The University of Texas at El Paso
500 W. University Ave., Civil Engineering
El Paso, TX 79968
(915) 747-8729
wswalker2@utep.edu